Skip to main content

Glossary of Terms

ABSORPTANCEThe ratio of the radiation absorbed by a surface to the total energy falling on that surface described as a percentage. The ratio of the radiation absorbed by a surface to the total energy falling on that surface described as a percentage.
ACCESS CHARGEA charge paid by all market participants withdrawing energy from the ISO controlled grid. The access charge will recover the portion of a utility's transmission revenue requirement not recovered through the variable usage charge.
ACOP (Adjusted Coefficient of Performance)A standard rating term that was used to rate the efficiency of heat pumps in California. ACOP was replaced by Heating Seasonal Performance Factor (HSPF) in 1988.
ACTIVE SOLAR ENERGYSolar radiation used by special equipment to provide space heating, hot water or electricity.
ACTIVE SOLAR ENERGY SYSTEMA system designed to convert solar radiation into usable energy for space, water heating, or other uses. It requires a mechanical device, usually a pump or fan, to collect the sun's energy.
ADDITIONAn alteration to an existing building that increases conditioned space.
ADJUSTMENT BIDA bid that is used by the ISO to adjust supply or demand when congestion is anticipated.
ADVERSE HYDROWater conditions limiting the production of hydroelectric power. In years having belownormal levels of rain and snow, and in seasons having less than usual runoff from mountain snowpack, there is then less water available for hydro energy production.
AFTER-MARKETbroad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles.
AFUE (Annual Fuel Utilization Efficiency)A measure of heating efficiency, in consistent units, determined by applying the federal test method for furnaces. This value is intended to represent the ratio of heat transferred to the conditioned space by the fuel energy supplied over one year.
AGGREGATORAn entity responsible for planning, scheduling, accounting, billing, and settlement for energy deliveries from the aggregator's portfolio of sellers and/or buyers. Aggregators seek to bring together customers or generators so they can buy or sell power in bulk, making a profit on the transaction.
AIR-TO-AIR HEAT EXCHANGERA device with separate air chambers that transfers heat between the conditioned air being exhausted and the outside air being supplied to a building.
AIR CHANGEThe replacement of a quantity of air in a space within a given period of time, typically expressed as air changes per hour. If a building has one air change per hour, this is equivalent to all of the air in the building being replaced in a onehour period.
AIR CONDITIONERAn assembly of equipment for air treatment consisting of a means for ventilation, air circulation, air cleaning, and heat transfer (either heating or cooling). The unit usually consists of an evaporator or cooling coil, and an electricallydriven compressor and condenser combination.
AIR FILMA layer of still air adjacent to a surface which provides some thermal resistance.
AIR FILM COEFFICIENTA measure of the heat transfer through an air film. [See ASHRAE Table 1, ASHRAE Handbook, 1985 Fundamentals]
AIR POLLUTIONUnwanted particles, mist or gases put into the atmosphere as a result of motor vehicle exhaust, the operation of industrial facilities or other human activity./
ALCOHOL FUELSA class of liquid chemicals that have certain combinations of hydrogen, carbon and oxygen, and that are capable of being used as fuel.
ALTERATIONAny change or modification to a building's construction. [See Addition].
ALTERNATING CURRENT(AC) Flow of electricity that constantly changes direction between positive and negative sides. Almost all power produced by electric utilities in the United States moves in current that shifts direction at a rate of 60 times per second.
ALTERNATIVE FUEL VEHICLE (AFV)motor vehicles that run on fuels other than petroleumbased fuels. As defined by the National Energy Policy Act (EPAct), this excludes reformulated gasoline as an alternative fuel.
ALTERNATIVE (transportation) FUELSas defined by the National Energy Policy Act (EPAct) the fuels are: methanol, denatured ethanol and other alcohols, separately or in mixtures of 85 percent by volume or more (or other percentage not less than 70 percent as determined by U.S. Department of Energy rule) with gasoline or other fuels; CNG; LNG; LPG; hydrogen; "coalderived liquid fuels;" fuels "other than alcohols" derived from "biological materials;" electricity, or any other fuel determined to be "substantially not petroleum" and yielding "substantial energy security benefits and substantial environmental benefits."
AMBIENTThe surrounding atmosphere; encompassing on all sides; the environment surrounding a body but undisturbed or unaffected by it.
AMBIENT AIR TEMPERATURESurrounding temperature, such as the outdoor air temperature around a building.
AMPERE (Amp)The unit of measure that tells how much electricity flows through a conductor. It is like using cubic feet per second to measure the flow of water. For example, a 1,200 watt, 120volt hair dryer pulls 10 amperes of electric current (watts divided by volts).
ANCILLARY SERVICESServices that the Independent System Operator may develop, in cooperation with market participants, to ensure reliability and to support the transmission of energy from generation sites to customer loads. Such services may include: regulation, spinning reserve, nonspinning reserve, replacement reserve, voltage support, and black start.
ANCILLARY SERVICESThe services other than scheduled energy that are required to maintain system reliability and meet WSCC/NERC operating criteria. Such services include spinning, nonspinning, and replacement reserves, voltage control, and black start capability.
ANGLE OF INCIDENCEThe angle that the sun's rays make with a line perpendicular to a surface. The angle of incidence determines the percentage of direct sunshine intercepted by a surface.
ANIMAL WASTE CONVERSIONProcess of obtaining energy from animal wastes. This is a type of biomass energy.
ANNUAL MAXIMUM DEMANDThe greatest of all demands of the electrical load which occurred during a prescribed interval in a calendar year.
ANSIAmerican National Standards Institute is the national organization that coordinates development and maintenance of consensus standards and sets rules for fairness in their development. ANSI also represents the USA in developing international standards.
ANTHRACITEHard coal, found deep in the earth. It burns very hot, with little flame. It usually has a heating value of 12,00015,000 British thermal units (Btus) per pound.
APPLIANCE EFFICIENCY STANDARDSAppliance Efficiency Standards regulate the minimum performance requirements for appliances sold in California and apply to refrigerators, freezers, room air conditioners, central air conditioners, gas space heaters, water heaters, plumbing fittings, fluorescent lamp ballasts and luminaires, and ignition devices for gas cooking appliances and gas pool heaters. New National Appliance Standards are in place for some of these appliances and will become effective for others at a future date.
APPLIANCE SATURATIONA percentage telling what proportion of all households in a given geographical area have a certain appliance.
APPLICANTApplicant means any person who submits an application for certification pursuant to the provisions of this division, including, but not limited to, any person who explores for or develops geothermal resources.
APPLICATIONApplication means any request for certification of any site and related facility filed in accordance with the procedures established pursuant to this division. An applicant for a geothermal powerplant and related facilities may propose more than one site and related geothermal facilities in the same application.
AREA LOADThe total amount of electricity being used at a given point in time by all consumers in a utility's service territory.
ASHNonorganic, nonflammable substance left over after combustible material has been completely burned.
ASHRAEAcronym for American Society of Heating, Refrigerating and Air Conditioning Engineers.
ASSOCIATED GASNatural gas that can be developed for commercial use, and which is found in contact with oil in naturally occurring underground formations.
ATGASSynthetic gas produced by dissolving coal in a bath of molten iron. The process was developed by Applied Technology, Inc. Synthetic gas may be used as a substitute for natural gas in industrial and home uses.
ATOMThe smallest unit of an element consisting of a dense positively charged nucleus (of protons and neutrons) orbited by negatively charged electrons.
ATOMIC ENERGY COMMISSIONThe independent civilian agency of the federal government with statutory responsibility to supervise and promote use of nuclear energy. Functions were taken over in 1974 by the Energy Research and Development Administration (now part of the U.S. Department of Energy) and the Nuclear Regulatory Commission.
ATOMIC NUCLEUSThe positively charged core of an atom.
AUXILIARY ENERGY SUBSYSTEMEquipment using conventional fuel to supplement the energy output of a solar system. This might be, for example, an oil fueled generator that adds to the electrical output of a substitutes for the solar system during long overcast periods when there is not enough sunlight.
AUXILIARY EQUIPMENTExtra machinery needed to support the operation of a power plant or other large facility.
AVERAGE COSTThe revenue requirement of a utility divided by the utility's sales. Average cost typically includes the costs of existing power plants, transmission, and distribution lines, and other facilities used by a utility to serve its customers. It also included operating and maintenance, tax, and fuel expenses.
AVERAGE DEMANDThe energy demand in a given geographical area over a period of time. For example, the number of kilowatthours used in a 24hour period, divided by 24, tells the average demand for that period.
AVERAGE HYDRORain, snow and runoff conditions that provide water for hydroelectric generation equal to the most commonly occurring levels. Average hydro usually is a mean indicating the levels experienced most often in a 104year period.
AVOIDED COSTThe cost the utility would incur but for the existence of an independent generator or other energy service option. Avoided cost rates have been used as the power purchase price utilities offer independent suppliers (see Qualifying Facilities).
AVOIDED COST(Regulatory) The amount of money that an electric utility would need to spend for the next increment of electric generation to produce or purchase elsewhere the power that it instead buys from a cogenerator or smallpower producer. Federal law establishes broad guidelines for determining how much a qualifying facility (QF) gets paid for power sold to the utility.
AZIMUTHThe angular distance between true south and the point on the horizon directly below the sun. Typically used as an input for opaque surfaces and windows in computer programs for calculating the energy performance of buildings.
BALANCED SCHEDULEA Scheduling Coordinator's schedule is balanced when generation, adjusted for transmission losses, equals demand.
BALLASTA device that provides starting voltage and limits the current during normal operation in electrical discharge lamps (such as fluorescent lamps).
BARRELIn the petroleum industry, a barrel is 42 U.S. gallons. One barrel of oil has an energy content of 6 million British thermal units. It takes one barrel of oil to make enough gasoline to drive an average car from Los Angeles to San Francisco and back (at 18 miles per gallon over the 700mile round trip).
BARRELS PER DAY EQUIVALENT (BPDEquivalent) A unit of measure that tells how much oil would have to be burned to produce the same amount of energy. For example, California's hydroelectric generation in 1983 was 58,000 barrels per day equivalent.
BASE LOADThe lowest level of power production needs during a season or year.
BASE LOAD UNITA power generating facility that is intended to run constantly at near capacity levels, as much of the time as possible.
BASE RATEThat portion of the total electric or gas rate covering the general costs of doing business unrelated to fuel expenses.
BASELINE FORECASTA prediction of future energy needs which does not take into account the likely effects of new conservation programs that have not yet been started.
BATTERYA device that stores energy and produces electric current by chemical action.
BENZENEA type of colorless liquid hydrocarbon that can be used as a motor fuel. Its chemical symbol is C6H6.
BGPThe acronym for Burbank, Glendale and Pasadena, three electric, municipal utilities serving those southern California cities. The three are usually grouped statistically, though they are separate entitites.
BI-FUEL VEHICLEA vehicle with two separate fuel systems designed to run on either fuel, using only one fuel at a time. These systems are advantageous for drivers who do not always have access to an alternative fuel refueling station. Bifuel systems are usually used in lightduty vehicles. One of the two fuels is typically an alternative fuel.
BI-GASA process being developed as a means of making synthetic gas from coal. The synthetic gas would be intended to substitute for natural gas in meeting industrial and home energy needs.
BILATERAL CONTRACTA twoparty agreement for the purchase and the sale of energy products and services.
BIOCONVERSIONProcesses that use plants or microorganisms to change one form of energy into another. For example, an experimental process uses algae to convert solar energy into gas that could be used for fuel.
BIODIESELa biodegradable transportation fuel for use in diesel engines that is produced through the transesterfication of organically derived oils or fats. It may be used either as a replacement for or as a component of diesel fuel.
BIOFUELSBiofuels are a wide range of fuels which are in some way derived from biomass. The term covers solid biomass, liquid fuels and various biogases.
BIOGASBiogas is methane produced by the process of anaerobic digestion of organic material by anaerobes. It can be produced either from biodegradable waste materials or by the use of energy crops fed into anaerobic digesters to supplement gas yields. The solid byproduct, digestate, can be used as a biofuel or a fertilizer. Biogas can be recovered from mechanical biological treatment waste processing systems. Farmers can produce biogas from manure from their cows by getting an anaerobic digester (AD).
BIOMASSEnergy resources derived from organic matter. These include wood, agricultural waste and other livingcell material that can be burned to produce heat energy. They also include algae, sewage and other organic substances that may be used to make energy through chemical processes.
BIOSPHEREThe zone at and adjacent to the earth's surface where all life exists; all living organisms of the earth.
BITUMINOUS COALSoft coal containing large amounts of carbon. It has a luminous flame and produces a great deal of smoke.
BLACKOUTA power loss affecting many electricity consumers over a large geographical area for a significant period of time.
BOILERA closed vessel in which water is converted to pressurized steam.
BOILING WATER REACTOR(BWR) A nuclear power unit in which water used as a coolant is allowed to boil at the core. The resulting steam may be used to drive electric turbines.
BOTTLED GASThe liquified petroleum gases propane and butane, contained under moderate pressure (about 125 pounds per square inch and 30 pounds per square inch respectively), in cylinders.
BOTTOMING CYCLEA means to increase the thermal efficiency of a steam electric generating system by converting some waste heat from the condenser into electricity rather than discharging all of it into the environment.
BREEDERA nuclear reactor that produces more fuel than it consumes. The breeder, invented in the United States, is used as a power source in several European countries.
BRITISH THERMAL UNIT (Btu)The standard measure of heat energy. It takes one Btu to raise the temperature of one pound of water by one degree Fahrenheit at sea level. For example, it takes about 2,000 Btu to make a pot of coffee. One Btu is equivalent to 252 calories, 778 footpounds, 1055 joules, and 0.293 watthours. Note: In the abbreviation, only the B is capitalized.
BROKERA retail agent who buys and sells power. The agent may also aggregate customers and arrange for transmission, firming and other ancillary services as needed.
BROWNOUTA controlled power reduction in which the utility decreases the voltage on the power lines, so customers receive weaker electric current. Brownouts can be used if total power demand exceeds the maximum available supply. The typical household does not notice the difference.
BUILDING ENVELOPEThe assembly of exterior partitions of a building which enclose conditioned spaces, through which thermal energy may be transferred to or from the exterior, unconditioned spaces, or the ground.
BULK POWER SUPPLYOften this term is used interchangeably with wholesale power supply. In broader terms, it refers to the aggregate of electric generating plants, transmission lines, and relatedequipment. The term may refer to those facilities within one electric utility, or within a group of utilities in which the transmission lines are interconnected.
BUNKER C FUEL OILA very heavy substance, left over after other fuels have been distilled from crude oil. Also called NO. 6 FUEL, it is used in power plants, ships and large heating installations. California's Bunker C fuel oil has high sulfur content, which causes air quality concerns when burned as fuel.
BUSBARIn electric utility operations, a busbar is a conductor that serves as a common connection for two or more circuits. It may be in the form of metal bars or hightension cables.
BUTANEA hydrocarbon gas found in the earth along with natural gas and oil. Butane turns into a liquid when put under pressure. It is sold as bottled gas. It is used to run heaters, stoves and motors, and to help make petrochemicals.
BUY THROUGHAn agreement between utility and customer to import power when the customer's service would otherwise be interrupted.
BUYERAn entity that purchases electrical energy or services from the Power Exchange (PX) or through a bilateral contract on behalf of enduse customers.
CALL-BACKA provision included in some power sale contracts that lets the supplier stop delivery when the power is needed to meet certain other obligations.
CALORIEOne energy calorie is equivalent to 4.2 joules. Thus, it takes 500,000 calories of energy to boil a pot of coffee. One food calorie equals 1,000 energy calories.
CALORIE (energy caloriesmall "c" as opposed to food Calorie capital "C") Any of several approximately equal values of heat, each measured as the quantity of heat require to raise the temperature of 1 gram of water by 1 degree Celsius from a standard initial temperature, esp. from 3.98 degress Celsius. 14.5 degrees Celsius, or 19.5 degrees Celsius, at 1 atmosphere pressure. A calorie is the unit of heat equal to 4.184 joules.
CAPACITYThe amount of electric power for which a generating unit, generating station, or other electrical apparatus is rated either by the user or manufacturer. The term is also used for the total volume of natural gas that can flow through a pipeline over a given amount of time, considering such factors as compression and pipeline size. There are various types of electricity capacity : Dependable Capacity: The systems's ability to carry the electric power for the time inrval and period specific, when related to the characteristics of the load to be supplied. Dependable capacity is determined by such factors as capability, operating power factor, weather, and portion of the load the station is to supply. Installed (or Nameplate) Capacity: The total manufacturer-rated capacities of equipment such as turbines, generators, condensers, transformers, and other system components. Peaking Capacity: The capacity of generating equipment intended for operation during the hours of highest daily, weekly or seasonal loads. Purchased Capacity: The amount of energy and capacity available for purchase from outside the system. Reserve Capacity: Extra generating capacity available to meeet peak or abnormally high demands for power and to generate power during scheduled or unscheduled outages. Units available for service, but not maintained at operating temperature, are termed "cold." those units ready and avaiable for service, though not in actual operation, are termed "hot."
CAPACITY FACTORA percentage that tells how much of a power plant's capacity is used over time. For example, typical plant capacity factors range as high as 80 percent for geothermal and 70 percent for cogeneration.
CAPACITY RELEASEA secondary market for capacity that is contracted by a customer which is not using all of its capacity.
CAPTIVE CUSTOMERA customer who does not have realistic alternatives to buying power from the local utility, even if that customer had the legal right to buy from competitors.
CARBON DIOXIDEA colorless, odorless, nonpoisonous gas that is a normal part of the air. Carbon dioxide, also called CO2, is exhaled by humans and animals and is absorbed by green growing things and by the sea.
CARBON MONOXIDE (CO)A colorless, odorless, highly poisonous gas made up of carbon and oxygen molecules formed by the incomplete combustion of carbon or carbonaceous material, including gasoline. It is a major air pollutant on the basis of weight.
CARCINOGENSPotential cancercausing agents in the environment. They include among others: industrial chemical compounds found in food additives, pesticides and fertilizers, drugs, toy, household cleaners, toiletries and paints. Naturally occurring ultraviolet solar radiation is also a carcinogen.
CATALYTIC CRACKINGA refinery process that converts a highboiling range fraction of petroleum (gas oil) to gasoline, olefin feed for alkylation, distillate, fuel oil and fuel gas by use of a catalyst and heat.
CAULKINGMaterial used to make an airtight seal by filling in cracks, such as those around windows and doors.
CCRCalifornia Code of Regulations.
CELSIUSA temperature scale based on the freezing (0 degrees) and boiling (100 degrees) points of water. Abbreviated as C in second and subsequent references in text. Formerly known as Centigrade. To convert Celsius to Fahrenheit, multiply the number by 9, divide by 5, and add 32. For example: 10 degrees Celsius x 9 = 90; 90 / 5 = 18; 18 + 32 = 50 degrees Fahrenheit.
CERTIFICATIONprocess by which a motor vehicle, motor vehicle engine, or motor vehicle pollution control device satisfies the criteria adopted by the California Air Resources Board (ARB) for the control of specified air contaminants from vehicular sources (Health & Safety Code, Section 39018). Certification constitutes a guarantee by the manufacturer that the engine will meet certain standards at 50,000 miles; if not, it must be replaced or repaired without change.
CFCs (CHLOROFLUOROCARBONS or CHLORINATED FLUOROCARBONS)A family of artificially produced chemicals receiving much attention for their role in stratospheric ozone depletion. On a per molecule basis, these chemicals are several thousand times more effective as greenhouse gases than carbon dioxide. Since they were introduced in the mid1930s, CFCs have been used as refrigerants, solvents and in the production of foam material. The 1987 Montreal protocol on CFCs seeks to reduce their production by onehalf by the year 1998.
CFM (cubic feet per minute)A measure of flow rate. CURIE A measure of radioactivity.
CHEMICAL ENERGYThe energy generated when a chemical compound combusts, decomposes, or transforms to produce new compounds.
CHILLERA device that cools water, usually to between 40 and 50 degrees Fahrenheit for eventual use in cooling air.
CIRCUITOne complete run of a set of electric conductors from a power source to various electrical devices (appliances, lights, etc.) and back to the same power source.
CLEAN FUEL VEHICLEis frequently incorrectly used interchangeably with "alternative fuel vehicle." Generally, refers to vehicles that use lowemission, cleanburning fuels. Public Resources Code Section 25326 defines clean fuels, for purposes of the section only, as fuels designated by ARB for use in LEVs, ULEVs or ZEVs and include, but are not limited to, electricity, ethanol, hydrogen, liquefied petroleum gas, methanol, natural gas, and reformulated gasoline.
CLERESTORYA wall with windows that is between two different (roof) levels. The windows are used to provide natural light into a building.
CLIMATE ZONEA geographical area is the state that has particular weather patterns. These zones are used to determine the type of building standards that are required by law.
CLUNKERSalso known as grosspolluting or super emitting vehicles, i.e., vehicles that emit far in excess of the emission standards by which the vehicle was certified when it was new.
CO-OPThis is the commonly used term for a rural electric cooperative. Rural electric cooperatives generate and purchase wholesale power, arrange for the transmission of that power, and then distribute the power to serve the demand of rural customers. Coops typically become involved in ancillary services such as energy conservation, load management and other demandside management programs in order to serve their customers at least cost.
COALBlack or brown rock, formed under pressure from organic fossils in prehistoric times, that is mined and burned to produce heat energy.
COAL CONVERSIONChanging coal into synthetic gas or liquid fuels. See GASIFICATION.
COAL OILOil that can be obtained by distilling bituminous coal.
COAL SEAMA mass of coal, occurring naturally at a particular location, that can be commercially mined.
COAL SLURRY PIPELINEA pipe system that transports pulverized coal suspended in water.
COGENERATIONCogeneration means the sequential use of energy for the production of electrical and useful thermal energy. The sequence can be thermal use followed by power production or the reverse, subject to the following standards:(a) At least 5 percent of the cogeneration project's total annual energy output shall be in the form of useful thermal energy.(b) Where useful thermal energy follows power production, the useful annual power output plus onehalf the useful annual thermal energy output equals not less than 42.5 percent of any natural gas and oil energy input.
COGENERATORCogenerators use the waste heat created by one process, for example during manufacturing, to produce steam which is used, in turn, to spin a turbine and generate electricity. Cogenerators may also be QFs.
COKEA porous solid left over after the incomplete burning of coal or of crude oil.
COKE OVEN GASGas given off by coke ovens. Coke oven gas is interchangeable with goal gas.
COMBINED CYCLE PLANTAn electric generating station that uses waste heat from its gas turbines to produce steam for conventional steam turbines.
COMBINED HYDRONIC SPACE/WATER HEATINGa system in which both space heating and domestic water heating are provided by the same water heater(s).
COMBUSTION BurningRapid oxidation, with the release of energy in the form of heat and light.
COMFORT CONDITIONINGThe process of treating air to simultaneously control its temperature, humidity, cleanliness, and distribution to meet the comfort requirements of the occupants of the conditioned space.
COMFORT ZONEThe range of temperatures over which the majority of persons feel comfortable (neither too hot nor too cold).
COMMERCIALIZATIONPrograms or activities that increase the value or decrease the cost of integrating new products or services into the electricity sector. (See "Sustained Orderly Development.")
COMPETITIVE TRANSMISSION CHARGEA nonbypassable charge that customers pay to a utility for the recovery of its stranded costs.
COMPRESSED NATURAL GAS (CNG)natural gas that has been compressed under high pressure, typically between 2,000 and 3,600 pounds per square inch, held in a container. The gas expands when released for use as a fuel.
CONDENSATELiquid fuel obtained by burning gas or vapor produced from oil and gas wells.
CONDENSERA heat exchanger in which the refrigerant, compressed to a hot gas, is condensed to liquid by rejecting heat.
CONDITIONED FLOOR AREAThe floor area of enclosed conditioned spaces on all floors measured from the interior surfaces of exterior partitions for nonresidential buildings and from the exterior surfaces of exterior partitions for residential buildings. [See California Code of Regulations, Title 24, Section 25302]
CONDITIONED SPACEEnclosed space that is either directly conditioned space or indirectly conditioned space. [See California Code of Regulations, Title 24, Section 25302]
CONDITIONED SPACE, DIRECTLYAn enclosed space that is provided with heating equipment that has a capacity exceeding 10 Btus/(hrft2), or with cooling equipment that has a capacity exceeding 10 Btus/(hrft2). An exception is if the heating and cooling equipment is designed and thermostatically controlled to maintain a process environment temperature less than 65 degrees Fahrenheit or greater than 85 degrees Fahrenheit for the whole space the equipment serves. [See California Code of Regulations, Title 24, Section 2 5302]
CONDITIONED SPACE, INDIRECTLYEnclosed space that: (1) has a greater area weighted heat transfer coefficient (uvalue) between it and directly conditioned spaces than between it and the outdoors or unconditioned space; (2) has air transferred from directly conditioned space moving through it at a rate exceeding three air changes per hour.
CONDUCTANCEThe quantity of heat, in Btu's, that will flow through one square foot of material in one hour, when there is a 1 degree F temperature difference between both surfaces. Conductance values are given for a specific thickness of material, not per inch thickness.
CONDUCTIONThe transfer of heat energy through a material (solid, liquid or gas) by the motion of adjacent atoms and molecules without gross displacement of the particles.
CONDUCTIVITY (k)The quantity of heat that will flow through one square foot of homogeneous material, one inch thick, in one hour, when there is a temperature difference of one degree Fahrenheit between its surfaces.
CONGESTIONA condition that occurs when insufficient transfer capacity is available to implement all of the preferred schedules simultaneously.
CONGESTION MANAGEMENTAlleviation of congestion by the ISO.
CONSERVATIONSteps taken to cause less energy to be used than would otherwise be the case. These steps may involve improved efficiency, avoidance of waste, reduced consumption, etc. They may involve installing equipment (such as a computer to ensure efficient energy use), modifying equipment (such as making a boiler more efficient), adding insulation, changing behavior patterns, etc.
CONTINENTAL SHELFThe portion of the sea bottom that slopes gradually from the edge of a continent. Usually defined as areas where water is less than 200 meters or 600 feet deep.
CONTINGENCY PLANNINGThe Energy Commission's strategy to respond to impending energy emergencies such as curtailment or shortage of fuel or power because of natural disasters or the result of human or political causes, or a clear threat to public health, safety or welfare.
CONTRACT PATHThe most direct physical transmission tie between two interconnected entities. When utility systems interchange power, the transfer is presumed to take place across the "contract path," notwithstanding the electrical fact that power flow in the network will distribute in accordance with network flow conditions. This term can also mean to arrange for power transfer between systems. (See also Parallel path flow)
CONTRACTS FOR DIFFERENCES (CFD)A type of bilateral contract where the electric generation seller is paid a fixed amount over time which is a combination of the shortterm market price and an adjustment with the purchaser for the difference. For example, a generator may sell a distribution company power for ten years at 6cents/kilowatthour (kWh). That power is bid into Poolco at some low /kWh value (to ensure it is always taken). The seller then gets the market clearing price from the pool and the purchaser pays the producer the difference between the Poolco selling price and 6cents/kWh (or vice versa if the pool price should go above the contract price).
CONTROL AREAAn electric power system, or a combination of electric power systems, to which a common automatic generation control (AGC) is applied to match the power output of generating units within the area to demand.
CONVECTIONTransfer by the movement of fluid.
CONVECTIONHeat transfer by the movement of fluid.
CONVECTIONTransferring heat by moving air, or transferring heat by means of upward motion of particles of liquid or gas heat from beneath.
CONVENTIONAL GASNatural gas occurring in nature, as opposed to synthetic gas.
CONVERSIONdevice or kit by which a conventional fuel vehicle is changed to an alternative fuel vehicle.
CONVERSION FUEL FACTORA number stating units of one system in corresponding values of another system.
CONVERTED VEHICLEa vehicle originally designed to operate on gasoline that has been modified or altered to run on an alternative fuel.
CONVERTERAny technology that changes the potential energy in a fuel into a different from of energy such as heat or motion. The term also is used to mean an apparatus that changes the quantity or quality of electrical energy.
COOLING CAPACITY, LATENTAvailable refrigerating capacity of an air conditioning unit for removing latent heat from the space to be conditioned.
COOLING CAPACITY, SENSIBLEAvailable refrigerating capacity of an air conditioning unit for removing sensible heat from the space to be conditioned.
COOLING CAPACITY, TOTALAvailable refrigerating capacity of an air conditioner for removing sensible heat and latent heat from the space to be conditioned.
COOLING DEGREE DAYA unit of measure that indicates how heavy the air conditioning needs are under certain weather conditions.
COOLING LOADThe rate at which heat must be extracted from a space in order to maintain the desired temperature within the space.
COOLING LOAD TEMPERATURE DIFFERENCE (CLTD)A value used in cooling load calculations for the effective temperature difference (delta T) across a wall or ceiling, which accounts for the effect of radiant heat as well as the temperature difference.
COOLING TOWERA device for evaporatively cooling water by contact with air.
COOPERATIVE (Electric utility)A joint venture organized by consumers to make electric utility service available in their area.
COP (COEFFICIENT OF PERFORMANCE)Used to rate the performance of a heat pump, the COP is the ratio of the rate of useful heat output delivered by the complete heat pump unit (exclusive of supplementary heating) to the corresponding rate of energy input, in consistent units and under specific conditions. [See California Code of Regulations, Title 24, Section 21602(c)(4)]
CORDA measure of volume, 4 by 4 by 8 feet, used to define amounts of stacked wood available for use as fuel. Burned, a cord of wood produces about 5 million calories of energy.
CORPORATE AVERAGE FUEL ECONOMY (CAFE)A salesweighted average fuel mileage calculation, in terms of miles per gallon, based on city and highway fuel economy measurements performed as part of the federal emissions test procedures. CAFE requirements were instituted by the Energy Policy and Conservation Act of 1975 (89 Statute. 902) and modified by the Automobile Fuel Efficiency Act of 1980 (94 Statute. 1821). For major manufacturers, CAFE levels in 1996 are 27.5 miles per gallon for lightduty automobiles. CAFE standards also apply to some light trucks. The Alternative Motor Fuels Act of 1988 allows for an adjusted calculation of the fuel economy of vehicles that can use alternative fuels, including fuelflexible and dualfuel vehicles.
CRUDE OILPetroleum as found in the earth, before it is refined into oil products. Also called CRUDE.
CRUDE OIL STOCKSStocks held at refineries and at pipeline terminals. Does not include stocks held on leases (storage facilities adjacent to the wells). In California, crude oil stocks in 1990 are approximately 18 million barrels on any given day.
CUBIC FOOTThe most common unit of measurement of natural gas volume. It equals the amount of gas required to fill a volume of one cubic foot under stated conditions of temperature, pressure and water vapor. One cubic foot of natural gas has an energy content of approximately 1,000 Btus. One hundred (100) cubic feet equals one therm (100 ft3 = 1 therm).
DAY-AHEAD MARKETThe forward market for energy and ancillary services to be supplied during the settlement period of a particular trading day that is conducted by the ISO, the PX, and other Scheduling Coordinators. This market closes with the ISO's acceptance of the final dayahead schedule.
DAY-AHEAD SCHEDULEDayahead Schedule A schedule prepared by a Scheduling Coordinator or the ISO before the beginning of a trading day. This schedule indicates the levels of generation and demand scheduled for each settlement period of that trading day.
DAYLIGHTINGThe use of sunlight to supplement or replace electric lighting.
DAYLIGHTING CONTROLA control system that varies the light output of an electric lighting system in response to variations in available daylight.
DEEP MINING Extraction of coal or minerals at depths greater than 1,000 feet. Coal usually is deepmined at not more than 1,500 feet.
DEGREE DAYA unit, based upon temperature difference and time, used in estimating fuel consumption and specifying nominal annual heating load of a building. When the mean temperature is less than 65 degrees Fahrenheit the heating degree days are equal to the total number of hours that temperature is less than 65 degrees Fahrenheit for an entire year.
DEINTEGRATION(See disaggregation)
DELTAA difference in temperature. Often used in the context of the difference between the design indoor temperature and the outdoor temperature.
DEMANDThe rate at which energy is delivered to loads and scheduling points by generation, transmission or distribution facilities.
DEMAND BIDDemand Bid A bid into the PX indicating a quantity of energy or an ancillary service that an eligible customer is willing to purchase and, if relevant, the maximum price that the customer is willing to pay.
DEMAND BILLINGThe electric capacity requirement for which a large user pays. It may be based on the customer's peak demand during the contract year, on a previous maximum or on an agreed minimum. Measured in kilowatts.
DEMAND CHARGEThe sum to be paid by a large electricity consumer for its peak usage level.
DEMAND SIDE MANAGEMENT (DSM)The methods used to manage energy demand including energy efficiency, load management, fuel substitution and load building. See LOAD MANAGEMENT.
DEMAND SITE MANAGEMENTPlanning, implementation, and evaluation of utilitysponsored programs to influence the amount or timing of customers' energy use.
DEMAND (Utility) The level at which electricity or natural gas is delivered to users at a given point in time. Electric demand is expressed in kilowatts. 
DEMONSTRATIONThe application and integration of a new product or service into an existing or new system. Most commonly, demonstration involves the construction and operation of a new electric technology interconnected with the electric utility system to demonstrate how it interacts with the system. This includes the impacts the technology may have on the system and the impacts that the larger utility system might have on the functioning of the technology.
DENSITYThe mass of a unit volume of a substance.
DEPARTMENT OF ENERGY (US DOE)The federal department established by the Department of Energy Organization Act to consolidate the major federal energy functions into one cabinetlevel department that would formulate a comprehensive, balanced national energy policy. DOE's main headquarters are in Washington, D.C.
DEPENDABLE CAPACITYThe system's ability to carry the electric power for the time interval and period specified. Dependable capacity is determined by such factors as capability, operating power factor and portion of the load the station is to supply.
DEPLETABLE ENERGY SOURCES1) electricity purchased from a public utility 2) energy obtained from burning coal, oil, natural gas or liquefied petroleum gases.
DEREGULATIONThe elimination of regulation from a previously regulated industry or sector of an industry.
DERIVATIVESA specialized security or contract that has no intrinsic overall value, but whose value is based on an underlying security or factor as an index. A generic term that, in the energy field, may include options, futures, forwards, etc.
DIESEL OILFuel for diesel engines obtained from the distillation of petroleum. It is composed chiefly of aliphatic hydrocarbons. Its volatility is similar to that of gas oil. Its efficiency is measured by cetane number.
DIFFUSE RADIATIONSolar radiation, scattered by water vapor, dust and other particles as it passes through the atmosphere, so that it appears to come from the entire sky. Diffuse radiation is higher on hazy or overcast days than on clear days.
DIRECT ACCESSThe ability of a retail customer to purchase commodity electricity directly from the wholesale market rather than through a local distribution utility. (See also Retail Competition)
DIRECT CURRENT (DC)Electricity that flows continuously in the same direction.
DIRECT ENERGY CONVERSIONProduction of electricity from an energy source without transferring the energy to a working fluid or steam. For example, photovoltaic cells transform light directly into electricity. Direct conversion systems have no moving parts and usually produce direct current.
DIRECT EXPANSION(refrigeration) Any system that, in operation between an environment where heat is absorbed (heat source), and an environment into which unwanted heat is directed (heat sink) at two different temperatures, is able to absorb heat from the heat source at the lower temperature and reject heat to the heat sink at the higher temperature. The cooling effect is obtained directly from a fluid called a refrigerant that absorbs heat at a low temperature and pressure, and transfers heat at a higher temperature and higher pressure.
DIRECT RADIATIONRadiation that has traveled a straight path from the sun, as opposed to diffuse radiation.
DIRECT SOLAR GAINSolar energy collected from the sun (as heat) in a building through windows, walls, skylights, etc.
DIRECTLY CONDITIONED SPACESee conditioned space, directly.
DISAGGREGATIONThe functional separation of the vertically integrated utility into smaller, individually owned business units (i.e., generation, dispatch/control, transmission, distribution). The terms "deintegration," "disintegration" and "delamination" are sometimes used to mean the same thing. (See also "Divestiture.")
DISPATCHThe operating control of an integrated electric system to: Assign generation to specific generating plants and other sources of supply to effect the most reliable and economical supply as the total of the significant area loads rises or falls. Control operations and maintenance of highvoltage lines, substations and equipment, including administration of safety procedures. Operate the interconnection. Schedule energy transactions with other interconnected electric utilities.
DISSOLVED GASNatural gas that can be developed for commercial use, and which is found mixed with oil in naturally occurring underground formations.
DISTRIBUTED GENERATIONA distributed generation system involves small amounts of generation located on a utility's distribution system for the purpose of meeting local (substation level) peak loads and/or displacing the need to build additional (or upgrade) local distribution lines.
DISTRIBUTIONThe delivery of electricity to the retail customer's home or business through low voltage distribution lines.
DISTRIBUTION SYSTEM (Electric utility)The substations, transformers and lines that convey electricity from highpower transmission lines to ultimate consumers. See GRID.
DISTRIBUTION UTILITY (Disco)The regulated electric utility entity that constructs and maintains the distribution wires connecting the transmission grid to the final customer. The Disco can also perform other services such as aggregating customers, purchasing power supply and transmission services for customers, billing customers and reimbursing suppliers, and offering other regulated or nonregulated energy services to retail customers. The "wires" and "customer service" functions provided by a distribution utility could be split so that two totally separate entities are used to supply these two types of distribution services.
DIVESTITUREThe stripping off of one utility function from the others by selling (spinningoff) or in some other way changing the ownership of the assets related to that function. Most commonly associated with spinningoff generation assets so they are no longer owned by the shareholders that own the transmission and distribution assets. (See also "Disaggregation.")
DOSEThe amount of ionizing radiation energy absorbed per unit mass of irradiated material at a specific location, such as a part of a human body.
DOUBLE GLAZINGWindows having two sheets of glass with an airspace between.
DOWNSTREAMA term used in the petroleum industry referring to the refining, transportation and marketing side of the business.
DRY BULB TEMPERATUREA measure of the sensible temperature of air.
DRY HOLEA drilled well that does not yield gas and/or oil quantities or condition to support commercial production; also applied to gas that has been produced and from which liquid components have been removed.
DRY STEAMThe conventional type of geothermal energy used for electricity production in California. Dry steam captured at the earth's surface is used to run electric turbines. The principal dry steam resource area is the Geysers in Northern California; one of only two known areas in the world for dry steam the other being Larderello, Italy.
DUAL-DUCT SYSTEMA central plant heating , ventilation and air conditioning (HVAC ) system that produces conditioned air at two temperatures and humidity levels. The air is then supplied through two independent duct systems to the points of usage where mixing occurs.
DUAL-FUEL OR BIFUEL VEHICLE refers to a vehicle capable of operating on two different fuels, in distinct fueling systems, such as compressed natural gas and gasoline.
DUAL-PANED (double-glazed)Two panes of glass or other transparent material, separated by a space.
DUCTA passageway made of sheet metal or other suitable material used for conveying air or other gas at relatively low pressures.
DUMPExcess hydropower that cannot be stored or conserved. Also know as SPILL ENERGY.
ECOLOGYThe study of interrelationships of animals and plants to one another and to their environment.
ECONOMIC EFFICIENCYA term that refers to the optimal production and consumption of goods and services. This generally occurs when prices of products and services reflect their marginal costs. Economic efficiency gains can be achieved through cost reduction, but it is better to think of the concept as actions that promote an increase in overall net value (which includes, but is not limited to, cost reductions).
ECONOMIES OF SALEEconomies of scale exist where the industry exhibits decreasing average longrun costs with size.
ECONOMIZER AIRA ducting arrangement and automatic control system that allows a heating, ventilation and air conditioning (HVAC) system to supply up to 100 percent outside air to satisfy cooling demands, even if additional mechanical cooling is required.
ECONOMIZER WATERA system which uses either direct evaporative cooling, or a secondary evaporatively cooled water loop and cooling coil to satisfy cooling loads, even if additional mechanical cooling is required.
ECONOMY ENERGY (Electricity utility)Electricity purchased by one utility from another to take the place of electricity that would have cost more to produce on the utility's own system.
ECOSYSTEMThe interacting system of biological community and its nonliving environment.
EDISON, THOMAS ALVAThe "father" of the American energy industry, Thomas Edison was an American inventor who was born in 1847 and died in 1931. He patented a total of 1,093 inventions more than any other person in American history. Among the most important were the incandescent electric light bulb (1879), the phonograph (1877) and the movie projector (1893).
EEIEdison Electric Institute. An association of electric companies formed in 1933 "to exchange information on industry developments and to act as an advocate for utilities on subjects of national interest."
EER(Energy Efficiency Ratio) the ratio of cooling capacity of an air conditioning unit in Btus per hour to the total electrical input in watts under specified test conditions. California Code of Regulations, Section 1602(c)(6).
EER (Energy Efficiency Ratio)The ratio of cooling capacity of an air conditioning unit in Btus per hour to the total electrical input in watts under specified test conditions. [See California Code of Regulations, Title 20, Section 1602(c)(6)]
EFFICACY, LIGHTINGThe ratio of light from a lamp to the electrical power consumed, including ballast losses, expressed as lumens per watt.
EFFICIENCYThe ratio of the useful energy delivered by a dynamic system (such as a machine, engine, or motor) to the energy supplied to it over the same period or cycle of operation. The ratio is usually determined under specific test conditions.
ELCONElectricity Consumers Resources Council. ELCON is an association of 28 large industrial consumers of electricity. ELCON members account for over five percent of all electricity consumed in the United States. ELCON was formed in 1976 "to enable member companies to "work cooperatively for the development of coordinated, rational and consistent policies affecting electric energy supply and pricing at the federal, state, and local levels."
ELECTRIC GENERATORA device that converts a heat, chemical or mechanical energy into electricity.
ELECTRIC RADIANT HEATINGA heating system in which electric resistance is used to produce heat which radiates to nearby surfaces. There is no fan component to a radiant heating system.
ELECTRIC RESISTANCE HEATERA device that produces heat through electric resistance. For example, an electric current is run through a wire coil with a relatively high electric resistance, thereby converting the electric energy into heat which can be transferred to the space by fans.
ELECTRIC UTILITYAny person or state agency with a monopoly franchise (including any municipality), which sells electric energy to enduse customers; this term includes the Tennessee valley Authority, but does not include other Federal power marketing agency (from EPAct).
ELECTRICITYA property of the basic particles of matter. A form of energy having magnetic, radiant and chemical effects. Electric current is created by a flow of charged particles (electrons).
ELECTROLYSISBreaking a chemical compound down into its elements by passing a direct current through it. Electrolysis of water, for example, produces hydrogen and oxygen.
ELECTROMAGNETIC FIELDS (EMF)Ordinary every day use of electricity produces magnetic and electric fields. These 60 Hertz fields (fields that go back and forth 60 times a second) are associated with electrical appliances, power lines and wiring in buildings.
ELEMENTA substance consisting entirely of atoms of the same atomic number.
ELEVATION1) The height above sea level (altitude); 2) A geometrical projection, such as a building, on a plane perpendicular to the horizon.
EMBEDDED COSTS EXCEEDING MARKET PRICES (ECEMP)Embedded costs of utility investments exceeding market prices are: i) costs incurred pursuant to a regulatory or contractual obligation; 2) costs that are reflected in costbased rates; and 3) costbased rates that exceed the price of alternatives in the marketplace. ECEMPS may become "stranded costs" where they exceed the amount that can be recovered through the asset's sale. Regulatory questions involve whether such costs should be recovered by utility shareholders and if so, how they should be recovered. "Transition costs" are stranded costs which are charged to utility customers through some type of fee or surcharge after the assets are sold or separated from the verticallyintegrated utility. "Stranded assets" are assets which cannot be sold for some reason. The British nuclear plants are an example of stranded assets which no one would buy. (Also referred to as Transition Costs.)
EMERGENCY CORE COOLING SYSTEM (ECCS)Equipment designed to cool the core of a nuclear reactor in the event of a complete loss of the coolant.
EMISSION STANDARDThe maximum amount of a pollutant legally permitted to be discharged from a single source.
EMISSIVITYThe property of emitting radiation; possessed by all materials to a varying extent.
EMITTANCEThe emissivity of a material, expressed as a fraction. Emittance values range from 0.05 for brightly polished metals to 0.96 for flat black paint.
ENERGYThe capacity for doing work. Forms of energy include: thermal, mechanical, electrical and chemical. Energy may be transformed from one form into another.
ENERGY BUDGETA requirement in the Building Energy Efficiency Standards that a proposed building be designed to consume no more than a specified number of British thermal units (Btus) per year per square foot of conditioned floor area.
ENERGY CHARGEThe amount of money owed by an electric customer for kilowatthours consumed.
ENERGY CONSUMPTIONThe amount of energy consumed in the form in which it is acquired by the user. The term excludes electrical generation and distribution losses.
ENERGY EFFICIENCYUsing less energy/electricity to perform the same function. Programs designed to use electricity more efficiently doing the same with less. For the purpose of this paper, energy efficiency is distinguished from DSM programs in that the latter are utilitysponsored and financed, while the former is a broader term not limited to any particular sponsor or funding source. "Energy conservation" is a term which has also been used but it has the connotation of doing without in order to save energy rather than using less energy to do the some thing and so is not used as much today. Many people use these terms interchangeably.
ENERGY MANAGEMENT SYSTEMA control system (often computerized) designed to regulate the energy consumption of a building by controlling the operation of energy consuming systems, such as the heating, ventilation and air conditioning (HVAC), lighting and water heating systems.
ENERGY RESERVESThe portion of total energy resources that is known and can be recovered with presently available technology at an affordable cost.
ENERGY RESOURCESEverything that could be used by society as a source of energy.
ENERGY SECURITY/FUEL SECURITYpolicy that considers the risk of dependence on fuel sources located in remote and unstable regions of the world and the benefits of domestic and diverse fuel sources.
ENERGY/FUEL DIVERSITYpolicy that encourages the development of energy technologies to diversify energy supply sources, thus reducing reliance on conventional (petroleum) fuels; applies to all energy sectors.
ENTHALPYThe quantity of heat necessary to raise the temperature of a substance from one point to a higher temperature. The quantity of heat includes both latent and sensible.
ENTITLEMENTElectric energy or generating capacity that a utility has a right to access under power exchange or sales agreements.
ENVIRONMENTAL PROTECTION AGENCY (EPA)A federal agency created in 1970 to permit coordinated governmental action for protection of the environment by systematic abatement and control of pollution through integration or research, monitoring, standards setting and enforcement activities.
EPAThe Environmental Protection Agency. A federal agency charged with protecting the environment.
EPActThe Energy Policy Act of 1992 addresses a wide variety of energy issues. The legislation creates a new class of power generators, exempt wholesale generators (EWGs), that are exempt from the provisions of the Public Utilities Holding Company Act of 1935 and grants the authority to FERC to order and condition access by eligible parties to the interconnected transmission grid.
ESCOEfficiency Service Company A company that offers to reduce a client's electricity consumption with the cost savings being split with the client.
ESCOEfficiency Service Company. A company that offers to reduce a client's electricity consumption with the cost savings being split with the client.
ETHANOL (also know as Ethyl Alcohol or Grain Alcohol, CH3CH2OH)a liquid that is produced chemically from ethylene or biologically from the fermentation of various sugars from carbohydrates found in agricultural crops and cellulosic residues from crops or wood. Used in the United States as a gasoline octane enhancer and oxygenate, it increases octane 2.5 to 3.0 numbers at 10 percent concentration. Ethanol can also be used in higher concentration (E85) in vehicles optimized for its use.
ETHYL TERTIARY BUTYL ETHER (ETBE)an aliphatic ether similar to MTBE. This fuel oxygenate is manufactured by reacting isobutylene with ethanol. Having high octane and low volatility characteristics, ETBE can be added to gasoline up to a level of approximately 17 percent by volume. ETBE is used as an oxygenate in some reformulated gasolines.
ETHYLENEA colorless gas that burns and is an oil refinery product.
EV (ELECTRIC VEHICLE)a vehicle powered by electricity, usually provided by batteries but may also be provided by photovoltaic (solar) cells or a fuel cell.
EV (ELECTRIC VEHICLE)A vehicle powered by electricity, usually provided by batteries but may also be provided by photovoltaic (solar) cells or a fuel cell
EVAPORATIVE COOLINGCooling by exchange of latent heat from water sprays, jets of water, or wetted material.
EXCHANGE (Electric utility)Agreements between utilities providing for purchase, sale and trading of power. Usually relates to capacity (kilowatts) but sometimes energy (kilowatthours).
EXEMPT WHOLESALE GENERATOR (EWG)Created under the 1992 Energy Policy Act, these wholesale generators are exempt from certain financial and legal restrictions stipulated in the Public Utilities Holding Company Act of 1935.
EXFILTRATIONAir flow outward through a wall, building envelope, etc.
EXHAUSTAir removed deliberately from a space, by a fan or other means, usually to remove contaminants from a location near their source.
EXPORTS (Electric utility)Power capacity or energy that a utility is required by contract to supply outside of its own service area and not covered by general rate schedules.
EXTRA HIGH VOLTAGE (EHV)Voltage levels higher than those normally used on transmission lines. Generally EHV is considered to be 345,000 volts or higher.
FAHRENHEITA temperature scale in which the boiling point of water is 212 degrees and its freezing point is 32 degrees. To convert Fahrenheit to Celsius, subtract 32, multiply by 5, and divide the product by 9. For example: 100 degrees Fahrenheit 32 = 68; 68 x 5 = 340; 340 / 9 = 37.77 degrees Celsius.
FAN COILA component of a heating, ventilation and air conditioning (HVAC) system containing a fan and heating or cooling coil, used to distribute heated or cooled air.
FEDERAL EMERGENCY MANAGEMENT AGENCY (FEMA)The federal agency in charge of disaster recovery in locations that have been declared disaster areas by a state's Governor and the President of the United States.
FEDERAL ENERGY REGULATORY COMMISSION (FERC)An independent regulatory commission within the U.S. Department of Energy that has jurisdiction over energy producers that sell or transport fuels for resale in interstate commerce; the authority to set oil and gas pipeline transportation rates and to set the value of oil and gas pipelines for ratemaking purposes; and regulates wholesale electric rates and hydroelectric plant licenses.
FEEDSTOCKAny bulk raw material constituting the principal input for an industrial process. Bio-materials may be substituted for petrochemical feedstocks as petroleum prices rise. The filtered extract of the mash is the feedstock for the fermenter.
FENESTRATIONIn simplest terms, windows or glass doors. Technically fenestration is described as any transparent or translucent material plus any sash, frame, mullion or divider. This includes windows, sliding glass doors, French doors, skylights, curtain walls and garden windows.
FIRM ENERGYPower supplies that are guaranteed to be delivered under terms defined by contract.
FIRST-GENERATION BIOFUELSFirst-generation biofuels are biofuels made from sugar, starch, vegetable oil or animal fats using conventional technology. The basic feedstocks for the production of first generation biofuels are often seeds or grains such as sunflower seeds, which are pressed to yield vegetable oil that can be used in biodiesel, or wheat, which yields starch that is fermented into bioethanol.
FISSIONA release of energy caused by the splitting of an atom's nucleus. This is the energy process used in conventional nuclear power plants to make the heat needed to run steam electric turbines.
FISSIONABLE MATERIALA substance whose atoms can be split by slow neutrons. Uranium235, plutonium239 and uranium233 are fissionable materials.
FLARE GASUnwanted natural gas that is disposed of by burning as it is released from an oil field.
FLAT PLATEA device used to collect solar energy. It is a piece of metal painted black on the side facing the sun, to absorb the sun's heat.
FLEXIBLE FUEL VEHICLE (FFV)a vehicle that can operate on either alcohol fuels (methanol or ethanol) or regular unleaded gasoline or any combination of the two from the same tank.
FLUE GASGas that is left over after fuel is burned and which is disposed of through a pipe or stack to the outer air.
FLUIDIZED BED COMBUSTIONA process for burning powdered coal that is poured in a liquidlike stream with air or gases. The process reduces sulfur dioxide emissions from coal combustion.
FLUORESCENT LAMPA tubular electric lamp that is coated on its inner surface with a phosphor and that contains mercury vapor whose bombardment by electrons from the cathode provides ultraviolet light which causes the phosphor to emit visible light either of a selected color or closely approximating daylight.
FLUOROCARBON GASESPropellants used in aerosol products and refrigerants that are believed to be causing depletion of the earth's ozone shield. See CFCs.
FOOTCANDLEA unit of illuminance on a surface that is one foot from a uniform point source of light of one candle and is equal to one lumen per square foot.
FORCED AIR UNIT (FAU)A central furnace equipped with a fan or blower that provides the primary means for circulation of air.
FOSSIL FUELOil, coal, natural gas or their byproducts. Fuel that was formed in the earth in prehistoric times from remains of livingcell organisms.
FRACTIONAL DISTILLATIONthe process of refining crude oil into various oil products. The various products are separated out in the order of their boiling points.
FRAMING EFFECTSThe effect of framing (wood or metal studs, joists, beams, etc.) on the overall Uvalue of a wall, roof, floor, window or other building surface. Framing generally increases the UValue and decreases the RValue of insulated surfaces.
FRAMING PERCENTAGEThe area of actual framing in an envelope assembly divided by the overall area of the envelope assembly. This percentage is used to calculate the overall Uvalue of an assembly.
FREQUENCYThe number of cycles which an alternating current moves through in each second. Standard electric utility frequency in the United States is 60 cycles per second, or 60 Hertz.
FUELA substance that can be used to produce heat.
FUEL CELLA device or an electrochemical engine with no moving parts that converts the chemical energy of a fuel, such as hydrogen, and an oxidant, such as oxygen, directly into electricity. The principal components of a fuel cell are catalytically activated electrodes for the fuel (anode) and the oxidant (cathode) and an electrolyte to conduct ions between the two electrodes, thus producing electricity.
FUEL GASSynthetic gas used for heating or cooling. It has less energy content than pipelinequality gas.
FUEL OILPetroleum products that are burned to produce heat or power.
FUEL REPROCESSING (Nuclear)The means for obtaining usable, fissionable material from spent reactor fuel.
FUEL ROD (Nuclear)A long slender tube that holds fissionable material (fuel) for nuclear reactor use. Fuel rods are assembled into bundles called fuel elements or assemblies, which are loaded individually into the reactor core.
FUEL SECURITYSee Energy Security.
FUSION ENERGYA power source, now under development, based on the release of energy that occurs when atoms are combined under the most extreme heat and pressure. It is the energy process of the sun and the stars.
GALLONA unit of volume. A U.S. gallon has 231 cubic inches or 3.785 liters.
GASGaseous fuel (usually natural gas) that is burned to produce heat energy. The word also is used, colloquially, to refer to gasoline.
GAS SYNTHESISA method producing synthetic gas from coal. Also called the FISCHERTROPSCH PROCESS.
GAS UTILITYany person engaged in, or authorized to engage in, distributing or transporting natural gas, including, but not limited to, any such person who is subject to the regulation of the Public Utilities Commission.
GASIFICATIONThe process where biomass fuel is reacted with sub stoichiometric quantities of air and oxygen usually under high pressure and temperature along with moisture to produce gas which contains hydrogen, methane, carbon monoxide, nitrogen, water and carbon dioxide. The gas can be burned directly in a boiler, or scrubbed and combusted in an enginegenerator to produce electricity. The three types of gasification technologies available for biomass fuels are the fixed bed updraft, fixed bed downdraft and fluidized bed gasifiers. Gasification is also the production of synthetic gas from coal.
GASOHOLIn the United States, gasohol (E10) refers to gasoline that contains 10 percent ethanol by volume. This term was used in the late 1970s and early 1980s but has been replaced in some areas of the country by terms such as E10, Super Unleaded Plus Ethanol, or Unleaded Plus.
GASOLINEA light petroleum product obtained by refining oil, and used as motor vehicle fuel.
GENERAL LIGHTINGLighting designed to provide a substantially uniform level of illumination throughout an area, exclusive of any provision for special visual tasks or decorative effects.
GENERATION COMPANY (GENCO)A regulated or nonregulated entity (depending upon the industry structure) that operates and maintains existing generating plants. The Genco may own the generation plants or interact with the short term market on behalf of plant owners. In the context of restructuring the market for electricity, Genco is sometimes used to describe a specialized "marketer" for the generating plants formerly owned by a verticallyintegrated utility.
GENERATION DISPATCH AND CONTROLAggregating and dispatching (sending off to some location) generation from various generating facilities, providing backups and reliability services. Ancillary services include the provision of reactive power, frequency control, and load following.(Also see "Power Pool" and "Poolco" below.)
GEOTHERMAL ENERGYNatural heat from within the earth, captured for production of electric power, space heating or industrial steam.
GEOTHERMAL GRADIENTThe change in the earth's temperature with depth. As one goes deeper, the earth becomes hotter.
GEOTHERMAL STEAMSteam drawn from deep within the earth.
GIGAWATT HOUR (GWH)One million kilowatthours of electric power. .
GIGAWATT (GW)One thousand megawatts (1,000 MW) or, one million kilowatts (1,000,000 kW) or one billion watts (1,000,000,000 watts) of electricity. One gigawatt is enough to supply the electric demand of about one million average homes.
GLAZINGA covering of transparent or translucent material (typically glass or plastic) used for admitting light.
GREENHOUSE EFFECTThe presence of trace atmospheric gases make the earth warmer than would direct sunlight alone. These gases (carbon dioxide [CO2], methane [CH4], nitrous oxide [N2O], tropospheric ozone [O3], and water vapor [H2O]) allow visible light and ultraviolet light (shortwave radiation) to pass through the atmosphere and heat the earth's surface. This heat is reradiated from the earth in form of infrared energy (longwave radiation). The greenhouse gases absorb part of that energy before it escapes into space. This process of trapping the longwave radiation is known as the greenhouse effect. Scientists estimate that without the greenhouse effect, the earth's surface would be roughly 54 degrees Fahrenheit colder than it is today too cold to support life as we know it.
GREENHOUSE EFFECT (relating to buildings)The characteristic tendency of some transparent materials (such as glass) to transmit radiation with relatively short wavelengths (such as sunlight) and block radiation of longer wavelengths (such as heat). This tendency leads to a heat buildup within the space enclosed by such a material.
GRIDThe electric utility companies' transmission and distribution system that links power plants to customers through high power transmission line service (110 kilovolt [kv] to 765 kv); high voltage primary service for industrial applications and street rail and bus systems (23 kv138 kv); medium voltage primary service for commercial and industrial applications (4 kv to 35 kv); and secondary service for commercial and residential customers (120 v to 480 v). Grid can also refer to the layout of a gas distribution system of a city or town in which pipes are laid in both directions in the streets and connected at intersections.
GRIDA system of interconnected power lines and generators that is managed so that the generators are dispatched as needed to meet the requirements of the customers connected to the grid at various points. Gridco is sometimes used to identify an independent company responsible for the operation of the grid.
GROSS AREAThe area of a surface including areas not belonging to that surface (such as windows and doors in a wall).
GROSS NATIONAL PRODUCT (GNP)The total market value of the goods and services produced by a nation before deduction or depreciation charges and other allowance for capital consumption and is widely used as a measure of economic activity.
H-COAL PROCESSA means of making coal cleaner so it will produce less ash and less sulfur emissions.
HEAT BALANCEThe outdoor temperature at which a building's internal heat gain (from people, lights and machines) is equal to the heat loss through windows, roof and walls.
HEAT CAPACITYThe amount of heat necessary to raise the temperature of a given mass one degree. Heat capacity may be calculated by multiplying the mass by the specific heat.
HEAT ENGINEAn engine that converts heat to mechanical energy.
HEAT GAINan increase in the amount of heat contained in a space, resulting from direct solar radiation, heat flow through walls, windows, and other building surfaces, and the heat given off by people, lights, equipment, and other sources.
HEAT LOSSA decrease in the amount of heat contained in a space, resulting from heat flow through walls, windows, roof and other building surfaces and from exfiltration of warm air.
HEAT PUMPAn airconditioning unit which is capable of heating by refrigeration, transferring heat from one (often cooler) medium to another (often warmer) medium, and which may or may not include a capability for cooling. This reversecycle air conditioner usually provides cooling in summer and heating in winter.
HEAT RATEA number that tells how efficient a fuelburning power plant is. The heat rate equals the Btu content of the fuel input divided by the kilowatthours of power output.
HEAT STORMHeat storms occur when temperatures exceed 100 degrees Fahrenheit over a large area for three days in a row. Normal hot temperatures cause electricity demand to increase during the peak summertime hours of 4 to 7 p.m. when air conditioners are straining to overcome the heat. If a hot spell extends to three days or more, however, nighttime temperatures do not cool down, and the thermal mass in homes and buildings retains the heat from previous days. This heat buildup causes air conditioners to turn on earlier and to stay on later in the day. As a result, available electricity supplies are challenged during a higher, wider peak electricity consumption period.
HEAT TRANSFERFlow of heat energy induced by a temperature difference. Heat flow through a building envelope typically flows from a heated, or hot area to a cooled, or cold area.
HEATING DEGREE DAYA unit that measure the space heating needs during a given period of time.
HEATING LOADThe rate at which heat must be added to a space in order to maintain the desired temperature within the space.
HEATING VALUEThe amount of heat produced by the complete combustion of a given amount of fuel.
HEAVY WATERA type of hydrogen atom that may be used as fuel for fusion power plants. Also called DEUTERIUM, it is found in abundance in the seas.
HEDGING CONTRACTSContracts which establish future prices and quantities of electricity independent of the shortterm market. Derivatives may be used for this purpose. (See Contracts for Differences, Forwards, Futures Market, and Options.)
HELIOCHEMICALUsing solar radiation to cause chemical reactions.
HELIOTHERMALA process that uses the sun's rays to produce heat.
HERTZA unit of electromagnetic wave frequency that is equal to one cycle per second. It is named after Henrich R. Hertz.
HIGH-SULFUR COALCoal whose weight is more than one percent sulfur.
HORSEPOWER (HP)A unit for measuring the rate of doing work. One horsepower equals about threefourths of a kilowatt (745.7 watts).
HOT(Colloquial) The word is sometimes used to describe electric utility lines that are carrying electric currently. It also is used to refer to anything that is highly radioactive.
HOT DRY ROCKA geothermal resource created when impermeable, subsurface rock structures, typically granite rock 15,000 feet or more below the earth's surface, are heated by geothermal energy. The resource is being investigated as a source of energy production.
HVAC (Heating Ventilation and Air Conditioning)A system that provides heating, ventilation and/or cooling within or associated with a building.
HYBRID VEHICLEUsually a hybrid EV, a vehicle that employs a combustion engine system together with an electric propulsion system. Hybrid technologies expand the usable range of EVs beyond what an allelectricvehicle can achieve with batteries only.
HYDROELECTRIC POWERElectricity produced by falling water that turns a turbine generator. Also referred to as HYDRO.
HYDROELECTRIC SPILL GENERATIONHydroelectric generation in existence prior to January 1, 1998, that has no storage capacity and that, if backed down, would spill. This term also refers to a hydro resource that has exceeded or has inadequate storage capacity and is spilling, even though generators are operating at full capacity.
HYDRONIC HEATINGA system that heats a space using hot water which may be circulated through a convection or fan coil system or through a radiant baseboard or floor system.
HYDROTHERMAL SYSTEMSUnderground reservoirs that produce either dry steam or a mixture of steam and water.
HYGASA process that uses water to help produce pipelinequality gas from coal.
ILEV (Inherently Low Emission Vehicle)Term used by federal government for any vehicle that is certified to meet the California Air Resources Board's Low Emission Vehicle (LEV) standards for nonmethane organic gases and carbon monoxide, ULEV standards for nitrogen oxides and does not emit any evaporative emissions.
IMBALANCE ENERGYThe realtime change in generation output or demand requested by the ISO to maintain reliability of the ISOcontrolled grid. Sources of imbalance energy include regulation, spinning and nonspinning reserves, replacement reserve, and energy from other generating units that are able to respond to the ISO's request for more or less energy.
IMPORTS (Electric utility)Power capacity or energy obtained by one utility from others under purchase or exchange agreement.
IMPOUNDMENTA body of water confined by a dam, dike, floodgate or other artificial barrier.
IN-SITU COMBUSTIONAn experimental means of recovering hardtoget petroleum by burning some of the oil in its natural underground reservoir. Also called FIREFLOODING.
IN-SITU GASIFICATIONConverting coal into synthetic gas at the place where the coal is found in nature.
INCANDESCENT LAMPAn electric lamp in which a filament is heated by an electric current until it emits visible light.
INDEPENDENT POWER PRODUCERAn Independent Power Producer (IPP) generates power that is purchased by an electric utility at wholesale prices. The utility then resells this power to enduse customers. Although IPPs generate power, they are not franchised utilities, government agencies or QFs. IPPs usually do not own transmission lines to transmit the power that they generate.
INDIGENOUS ENERGY RESOURCESPower and heat derived from sources native to California. These include geothermal, hydro, biomass, solar and wind energy. The term usually is understood to include cogeneration facilities.
INDIRECTLY CONDITIONED SPACESee conditioned space, indirectly.
INFILTRATIONThe uncontrolled inward leakage of air through cracks and gaps in the building envelope, especially around windows, doors and duct systems.
INFILTRATION BARRIERA material placed on the outside or the inside of exterior wall framing to restrict inward air leakage, while permitting the outward escape of water vapor from the wall cavity.
INFRASTRUCTUREgenerally refers to the recharging and refueling network necessary to successful development, production, commercialization and operation of alternative fuel vehicles, including fuel supply, public and private recharging and refueling facilities, standard specifications for refueling outlets, customer service, education and training, and building code regulations.
INJECTION(Petroleum) Forcing gas or water into an oil well to increase pressure and cause more oil to come to the surface. See THERMALLY ENHANCED OIL RECOVERY.
INSOLATIONThe total amount of solar radiation (direct, diffuse, and reflected) striking a surface exposed to the sky.
INSULATION, THERMALA material having a relatively high resistance of heat flow and used principally to retard heat flow. See RVALUE.
INTEGRATED RESOURCE PLANNING PRINCIPLESThe underlying principles of IRP can be distinguished from the formal process of developing an approved utility resource plan for utility investments in supply and demandside resources. A primary principle is to provide a framework for comparing a variety of supply and demandside and transmission resource costs and attributes outside of the basic provision (or reduction) of electric capacity and energy. These resources may be owned or constructed by any entity and may be acquired through contracts as well as through direct investments. Another principle is the incorporation of risk and uncertainty into the planning analysis. The public participation aspects of IRP allow public and regulatory involvement in the planning rather than the siting stage of project development.
INTEGRATED RESOURCE PLANNING(IRP)A public planning process and framework within which the costs and benefits of both demand and supplyside resources are evaluated to develop the leasttotalcost mix of utility resource options. In many states, IRP includes a means for considering environmental damages caused by electricity supply/transmission and identifying cost
INTERCHANGE (Electric utility)The agreement among interconnected utilities under which they buy, sell and exchange power among themselves. This can, for example, provide for economy energy and emergency power supplies.
INTERCONNECTION (Electric utility)The linkage of transmission lines between two utilities, enabling power to be moved in either direction. Interconnections allow the utilities to help contain costs while enhancing system reliability.
INTERNAL COMBUSTION ENGINEAn engine in which fuel is burned inside the engine. A car's gasoline engine or rotary engine is an example of a internal combustion engine. It differs from engines having an external furnace, such as a steam engine.
INTERRUPTIBLE SERVICE (Electric utility)Electricity supplied under agreements that allow the supplier to curtail or stop service at times.
INTERTIEA transmission line that links two or more regional electric power systems.
IONAn atom or group of atoms that is electrically charged.
IOUAn investor owned utility. A company, owned by stockholders for profit, that provides utility services. A designation used to differentiate a utility owned and operated for the benefit of shareholders from municipally owned and operated utilities and rural electric cooperatives.
IPPINDEPENDENT POWER PRODUCER. An private entity that operates a generation facility and sells power to electric utilities for resale to retail customers.
ISDNINTEGRATED SERVICES DIGITAL NETWORK. A 128 Kbps(kilobytes per second) digital telephone service available in many parts of the country though not universally available thatmay be able to substitute for fiber optic cable in every respect except possibly television transmission.
ISOINDEPENDENT SYSTEM OPERATOR. A neutral operator responsible for maintaining instaneous balance of the grid system. The ISO performs its function by controlling the dispatch of flexible plants to ensure that loads match resources available to the system.
JOULEA unit of work or energy equal to the amount of work done when the point of application of force of 1 newton is displaced 1 meter in the direction of the force. It takes 1,055 joules to equal a British thermal unit. It takes about 1 million joules to make a pot of coffee.
kBtuOnethousand (1,000) Btus.
KEROSENECertain colorless, lowsulfur oil products that burn without producing much smoke.
KILOVOLT (kv)Onethousand volts (1,000). Distribution lines in residential areas usually are 12 kv (12,000 volts).
KILOWATT-HOUR (kWh)The most commonlyused unit of measure telling the amount of electricity consumed over time. It means one kilowatt of electricity supplied for one hour.
KILOWATT (kW)One thousand (1,000) watts. A unit of measure of the amount of electricity needed to operate given equipment. On a hot summer afternoon a typical home, with central air conditioning and other equipment in use, might have a demand of four kW each hour.
LANDFILL GASGas generated by the natural degrading and decomposition of municipal solid waste by anaerobic microorganisms in sanitary landfills. The gases produced, carbon dioxide and methane, can be collected by a series of lowlevel pressure wells and can be processed into a medium Btu gas that can be burned to generate steam or electricity.
LASERA very intense, uniform beam of electromagnetic radiation. Acronym for Light Amplification by Simulated Emission of Radiation.
LATENT HEATA change in the heat content that occurs without a corresponding change in temperature, usually accompanied by a change of state (as from liquid to vapor during evaporation).
LATENT LOADThe cooling load caused by moisture in the air.
LATITUDEThe angular distance north or south of the equator, measured in degrees of arc.
LAY UPLay up is another term for cold storage and describes the status of equipment (such as a power plant) that has been placed in storage ("mothballed") for latter use.
LAYOFF (Electric utility)Excess capacity of a generating unit, available for a limited time under the terms of a power sales agreement.
LEADED GASOLINEGasoline containing tetraethyl lead, an important constituent in antiknock gasoline. Leaded gasoline is no longer sold in the United States.
LIFE-CYCLE COSTAmount of money necessary to own, operate and maintain a building over its useful life.
LIFE EXTENSIONA term used to describe capital expenses which reduce operating and maintenance costs associated with continued operation of electric utility boilers. Such boilers usually have a 40 year operating life under normal circumstances.
LIFELINE RATESRates charged by a utility company for the low income, the disadvantaged and senior citizens. The rates provide a discount for minimum necessary utilities, such as electricity requirements of typically 300 to 400 kilowatt/hours per month.
LIGHT WATER REACTOR (LWR)A nuclear power unit that uses ordinary water to cool its core. The LWR may be a boiling water reactor or a pressurized water reactor.
LIGNITEBrownish black coal having qualities in between those of bituminous coal and peat. The texture of the original wood often is visible in lignite.
LIQUEFACTIONThe process of making synthetic liquid fuel from coal. The term also is used to mean a method for making large amounts of gasoline and heating oil from petroleum.
LIQUEFIED GASESGases that have been or can be changed into liquid form. These include butane, butylene, ethane, ethylene, propane and propylene.
LIQUID BRINEA type of geothermal energy resource that depends on naturally occurring hot water solution found within the earth. Technology for this novel energy source is being developed in the Salton Sea area in Southern California.
LNG (LIQUEFIED NATURAL GAS)Natural gas that has been condensed to a liquid, typically by cryogenically cooling the gas to minus 260 degrees Fahrenheit (below zero).
LOADThe amount of electric power supplied to meet one or more end user's needs.
LOADAn enduse device or an enduse customer that consumes power. Load should not be confused with demand, which is the measure of power that a load receives or requires.
LOAD CENTERSA geographical area where large amounts of power are drawn by endusers.
LOAD DIVERSITYThe condition that exists when the peak demands of a variety of electric customers occur at different times. This is the objective of "load molding" strategies, ultimately curbing the total capacity requirements of a utility.
LOAD FACTORA percent telling the difference between the amount of electricity a consumer used during a given time span and the amount that would have been used if the usage had stayed at the consumer's highest demand level during the whole time. The term also is used to mean the percentage of capacity of an energy facility such as power plant or gas pipeline that is utilized in a given period of time.
LOAD MANAGEMENTSteps taken to reduce power demand at peak load times or to shift some of it to offpeak times. This may be with reference to peak hours, peak days or peak seasons. The main thing affecting electric peaks is airconditioning usage, which is therefore a prime target for load management efforts. Load management may be pursued by persuading consumers to modify behavior or by using equipment that regulates some electric consumption.
LOOP FLOWThe difference between scheduled and actual power flows on electric transmission lines.
LOSSES (Electric utility)Electric energy or capacity that is wasted in the normal operation of a power system. Some kilowatthours are lost in the form of waste heat in electrical apparatus such as substation conductors. LINE LOSSES are kilowatts or kilowatthours lost in transmission and distribution lines under certain conditions.
LOW-EA special coating that reduces the emissivity of a window assembly, thereby reducing the heat transfer through the assembly.
LOW-SULFUR COALCoal having one percent or less of sulfur by weight.
LOW-SULFUR OILOil having one percent or less of sulfur by weight.
LOW EMISSION VEHICLE (LEV)a vehicle certified by the California Air Resources Board to have emissions from zero to 50,000 miles no higher than 0.075 grams/mile (g/mi) of nonmethane organic gases, 3.4 g/mi of carbon monoxide, and 0.2 g/mi of nitrogen oxides. Emissions from 50,000 to 100,000 miles may be slightly higher (See chart in Chapter 2.)
LPG (LIQUEFIED PETROLEUM GAS)A mixture of gaseous hydrocarbons, mainly propane and butane that change into liquid form under moderate pressure. LPG or propane is commonly used as a fuel for rural homes for space and water heating, as a fuel for barbecues and recreational vehicles, and as a transportation fuel. It is normally created as a byproduct of petroleum refining and from natural gas production.
LUMENA measure of the amount of light available from a light source equivalent to the light emitted by one candle.
LUMEN MAINTENANCE CONTROLAn electrical control device designed to vary the electrical consumption of a lighting system in order to maintain a specified illumination level.
LUMENS/WATTA measure of the efficacy of a light fixture; the number of lumens output per watt of power consumed.
LUMINAIREA complete lighting unit consisting of a lamp or lamps together with the parts designed to distribute the light, to position and protect the lamps and to connect the lamps to the power supply.
LUXA unit of illumination equal to the direct illumination on a surface that is everywhere one meter from a uniform point source of one candle; a unit of illumination that is equal to one lumen per square meter. Also see footcandle.
M100100 percent (neat) methanol used as a motor fuel in dedicated methanol vehicles, such as some heavyduty truck engines.
M85a blend of 85 percent methanol and 15 percent unleaded regular gasoline, used as a motor fuel.
MAGMAThe molten rock and elements that lie below the earthós crust. The heat energy can approach 1,000 degrees Fahrenheit and is generated directly from a shallow molten magma resource and stored in adjacent rock structures. To extract energy from magma resources requires drilling near or directly into a magma chamber and circulating water down the well in a convection type system.
MAGNETO HYDRO DYNAMICS (MHD)A means of producing electricity directly by moving liquids or gases through a magnetic field.
MAJOR MARKETERany person who sells natural gas or oil in amounts determined by the commission as having a major effect on energy supplies.
MAJOR NATURAL GAS PRODUCERany person who produces natural gas in amounts determined by the commission as having a major effect on energy supplies.
MAJOR OIL PRODUCERmeans any person who produces oil in amount determined by the commission as having a major effect on energy supplies.
MANUFACTURED GASGas produced by certain processes from oil, coal or coke.
MARGINAL COSTThe sum that has to be paid the next increment of product of service. The marginal cost of electricity is the price to be paid for kilowatthours above and beyond those supplied by presently available generating capacity.
MARGINAL COSTIn the utility context, the cost to the utility of providing the next (marginal)kilowatthour of electricity, irrespective of sunk costs.
MARKET-BASED PRICEA price set by the mutual decisions of many buyers and sellers in a competitive market.
MARKET CLEARING PRICEThe price at which supply equals demand. The Day Ahead and Hour Ahead Markets.
MARKET PARTICIPANTAn entity, including a Scheduling Coordinator, who participates in the energy marketplace through the buying, selling, transmission, or distribution of energy or ancillary services into, out of, or through the ISOcontrolled grid.
MARKETERAn agent for generation projects who markets power on behalf of the generator.The marketer may also arrange transmission, firming or other ancillary services as needed. Though a marketer may perform many of the same functions as a broker, the difference is that a marketer represents the generator while a broker acts as a middleman.
MARSH GASA common term for gas that bubbles to the surface of the water in a marsh or swamp. It is colorless, odorless and can be explosive.
MASTER FILEA file maintained by the PX for use in bidding and bid evaluation protocol that contains information on generating units, loads, and other resources eligible to bid into the PX.
MCFOne thousand cubic feet or natural gas, having an energy value of one million Btu. A typical home might use six MCF in a month.
MEGAWATT HOUR (MWh)One thousand kilowatthours, or an amount of electricity that would supply the monthly power needs of 1,000 typical homes in the Western U.S. (This is a rounding up to 8,760 kWh/year per home based on an average of 8,549 kWh used per household per year [U.S. DOE EIA, 1997 annual per capita electricity consumtpion figures]).
MEGAWATT (MW)One thousand kilowatts (1,000 kW) or one million (1,000,000) watts. One megawatt is enough energy to power 1,000 average homes.
METERA device for measuring levels and volumes of a customerós gas and electricity use.
METHANEA light hydrocarbon that is the main component of natural gas and marsh gas. It is the product of the anaerobic decomposition of organic matter, enteric fermentation in animals and is one of the greenhouse gases. Chemical formula is CH4.
METHANE (CH4)the simplest of hydrocarbons and the principal constituent of natural gas. Pure methane has a heating value of 1,1012 Btu per standard cubic foot.
METHANOL (also known as Methyl Alcohol, Wood Alcohol, CH3OH)a liquid formed by catalytically combining carbon monoxide (CO) with hydrogen (H2) in a 1:2 ratio, under high temperature and pressure. Commercially it is typically made by steam reforming natural gas. Also formed in the destructive distillation of wood.
METHYL TERTIARY BUTYL ETHER (MTBE)an ether manufactured by reacting methanol and isobutylene. The resulting ether has a high octane and low volatility. MTBE is a fuel oxygenate and is permitted in unleaded gasoline up to a level of 15 percent. It is one of the primary ingredients in reformulated gasolines.
MICROWAVEElectromagnetic radiation with wavelengths of a few centimeters. It falls between infrared and radio wavelengths on the electromagnetic spectrum. The radio wave beam can deliver electrical energy over long distances.
MILOnetenth of one cent $0.001.
MINIMUM GENERATIONGenerally, the required minimum generation level of a utility systemós thermal units. Specifically, the lowest level of operation of oilfired and gasfired units at which they can be currently available to meet peak load needs.
MONOPOLYThe only seller with control over market sales.
MONOPSONYThe only buyer with control over market purchases.
MTBE (METHYL TERTIARY-BUTYL ETHER)A clean burning oxygenate with high octane and low volatility added to unleaded gasoline to reduce carbon monoxide emissions.
MUNICIPAL ELECTRIC UTILITYA power utility system owned and operated by a local jurisdiction.
MUNICIPAL SOLID WASTELocally collected garbage, which can be processed and burned to produce energy.
MUNICIPAL UTILITYA provider of utility services owned and operated by a municipal government.
MUNICIPALIZATIONThe process by which a municipal entity assumes responsibility for supplying utility service to its constituents. In supplying electricity, the municipality may generate and distribute the power or purchase wholesale power from other generators and distribute it.
NARUCthe national association of regulatory utility commissioners. An advisory council composed of governmental agencies of the fifty States, the District of Columbia, Puerto Rico and the Virgin Islands engaged in the regulation of utilities and carriers. "The chief objective is to serve the consumer interest by seeking to improve the quality and effectiveness of public regulation in America."
NASUCAThe National Association of Utility Consumer Advocates. NASUCA includes members from 38 states and the District of Columbia. It was formed "to exchange information and take positions on issues affecting utility rates before federal agencies, Congress and the courts.
NATURAL GASHydrocarbon gas found in the earth, composed of methane, ethane, butane, propane and other gases.
NATURAL GAS VEHICLEvehicles that are powered by compressed or liquefied natural gas.
NATURAL GASOLINEA mixture of liquids extracted from natural gas and suitable for blending with ordinary oilderived gasoline.
NATURAL MONOPOLYA situation where one firm can produce a given level of output at a lower total cost than can any combination of multiple firms. Natural monopolies occur in industries which exhibit decreasing average longrun costs due to size (economies of scale). According to economic theory, a public monopoly governed by regulation is justified when an industry exhibits natural monopoly characteristics.
NCSLThe National Conference of State Legislatures. A national advisory council which provides services to state legislatures "by bringing together information from all states to forge workable answers to complex policy questions."
NEUTRONAn uncharged particle found in the nucleus of every atom except that of hydrogen.
NEWTONA unit of force. The amount of force it takes to accelerate one kilogram at one meter per second per second.
NGV (NATURAL GAS VEHICLE)vehicles that are powered by compressed or liquefied natural gas.
NON-DEPLETABLE ENERGY RESOURCESEnergy which is not obtained from depletable energy sources
NON-FIRM ENERGYElectricity that is not required to be delivered or to be taken under the terms of an electric purchase contract.
NONRESIDENTIAL BUILDINGany building which is heated or cooled in its interior, and is of an occupancy type other than Type H, I, or J, as defined in the Uniform Building Code, 1973 edition, as adopted by the International Conference of Building Officials.
NOPRA Notice of Proposed Rulemaking. A designation used by the FERC for some of its dockets.
NOxOxides of nitrogen that are a chief component of air pollution that can be produced by the burning of fossil fuels. Also called nitrogen oxides.
NRTANorthwest Regional Transmission Association. A subregional transmission group within the Western Regional Transmission Association.
NUCLEAR ENERGYPower obtained by splitting heavy atoms (fission) or joining light atoms (fusion). A nuclear energy plant uses a controlled atomic chain reaction to produce heat. The heat is used to make steam run conventional turbine generators.
NUCLEAR REGULATORY COMMISSION (NRC)An independent federal agency that ensures that strict standards of public health and safety, environmental quality and national security are adhered to by individuals and organizations possessing and using radioactive materials. The NRC is the agency that is mandated with licensing and regulating nuclear power plants in the United States. It was formally established in 1975 after its predecessor, the Atomic Energy Commission, was abolished.
NUGA nonutility generator. A generation facility owned and operated by an entity who is not defined as a utility in that jurisdictional area.
OAPECAcronym for Organization of Arab Petroleum Exporting Countries founded in 1968 for cooperation in economic and petroleum affairs. See OPEC.
OBLIGATION TO SERVEThe obligation of a utility to provide electric service to any customer who seeks that service, and is willing to pay the rates set for that service. Traditionally, utilities have assumed the obligation to serve in return for an exclusive monopoly franchise.
OCCUPANCY SENSORA control device that senses the presence of a person in a given space, commonly used to control lighting systems in buildings.
OCEAN THERMAL GRADIENT (OTG)Temperature differences between deep and surface water. Deep water is likely to be 25 to 45 degrees Fahrenheit colder. The term also refers to experimental technology that could use the temperature differences as a means to produce energy.
OCTANEA rating scale used to grade gasoline as to its antiknock properties. Also any of several isometric liquid paraffin hydrocarbons, C8H18. Normal octane is a colorless liquid found in petroleum boiling at 124.6 degrees Celsius.
OCTANE RATINGA measure of a gasolineàs resistance to exploding too early in the engine cycle, which causes knocking. The higher the rating, the lower the chance of premature ignition.
OFF­ROADAny non­stationary device, powered by an internal combustion engine or motor, used primarily off the highways to propel, move, or draw persons or property, and used in any of the following applications: marine vessels, construction/farm equipment, locomotives, utility and lawn and garden equipment, off­road motorcycles, and off­highway vehicles.
OHMA unit of measure of electrical resistance. One volt can produce a current of one ampere through a resistance of one ohm.
OIL SHALEA type of rock containing organic matter that produces large amounts of oil when heated to high temperatures.
OLIGOPOLYA few sellers who exert market control overprices.
OPECAcronym for Organization of Petroleum Exporting Countries founded in 1960 for unify and coordinate petroleum polices of the members. Headquarters is in Vienna, Austria.
OPTIONSAn option is a contractual agreement that gives the holder the right to buy (call option) or sell (put option) a fixed quantity of a security or commodity (for example, a commodity or commodity futures contract), at a fixed price, within a specified period of time. May either be standardized, exchangetraded, and government regulated, or overthecounter customized and nonregulated.
ORIENTATIONthe position of a building relative to the points of a compass.
ORIGINAL EQUIPMENT MANUFACTURER (OEM)refers to the manufacturers of complete vehicles or heavy­duty engines, as contrasted with remanufacturers, converters, retrofitters, upfitters, and repowering or rebuilding contractors who are overhauling engines, adapting or converting vehicles or engines obtained from the OEMs, or exchanging or rebuilding engines in existing vehicles.
OUTAGE (Electric utility)An interruption of electric service that is temporary (minutes or hours) and affects a relatively small area (buildings or city blocks). See BLACKOUT.
OUTER CONTINENTAL SHELF (OCS)The submerged lands extending from the out limit of the historic territorial sea (typically three miles) to some undefined outer limit, usually a depth of 600 feet. In the United States, this is the portion of the shelf under federal jurisdiction. See CONTINENTAL SHELF.
OUTSIDE AIRAir taken from outdoors and not previously circulated through the HVAC system.
OVER GENERATIONA condition that occurs when total PX participant demand is less that or equal to the sum of regulatory musttake generation, regulatory mustrun generation, and reliability mustrun generation.
OVERHANGAny horizontal projection that serves as a shading element for a window.
OXYGENATEa term used in the petroleum industry to denote octane components containing hydrogen, carbon and oxygen in their molecular structure. Includes ethers such as MTBE and ETBE and alcohols such as ethanol or methanol. The oxygenate is a prime ingredient in reformulated gasoline. The increased oxygen content given by oxygenates promotes more complete combustion, thereby reducing tailpipe emissions.
OZONEA kind of oxygen that has three atoms per molecule instead of the usual two. Ozone is a poisonous gas, but the ozone layer in the upper atmosphere shields life on earth from deadly ultraviolet radiation from space. The molecule contains three oxygen atoms (O3).
PADD (PETROLEUM ADMINISTRATION FOR DEFENSE DISTRICTS)The United States is divided by the U.S. Department of Energy into five PADD regions for planning purposes. The states within PADD V are Alaska, Arizona, California, Hawaii, Nevada, Oregon and Washington, which are linked closely by their oil supply network. Since very little petroleum product is export outside the district, PADD V is essentially a selfcontained oil supply system with Alaska and California the main producers and California refining the majority of the crude oil consumed in the PADD.
PARALLEL PATH FLOWAs defined by NERC, this refers to the flow of electric power on an electric system's transmission facilities resulting from scheduled electric power transfers between two other electric systems. (Electric power flows on all interconnected parallel paths in amounts inversely proportional to each path's resistance.)
PARTIAL LOADAn electrical demand that uses only part of the electrical power available.
PARTICULATE MATTER (PM)Unburned fuel particles that form smoke or soot and stick to lung tissue when inhaled. A chief component of exhaust emissions from heavyduty diesel engines.
PASSIVE SOLAR ENERGYUse of the sun to help meet a building¹s energy needs by means of architectural design (such as arrangement of windows) and materials (such as floors that store heat, or other thermal mass).
PASSIVE SOLAR SYSTEMA solar heating or cooling system that uses no external mechanical power to move the collected solar heat.
PBR -PERFORMANCE-BASED REGULATIONAny ratesetting mechanism which attempts to link rewards (generally profits) to desired results or targets. PBR sets rates, or components of rates,for a period of time based on external indices rather than a utility's costofservice. Other definitions include light
PCBs (POLYCHLORONATED BIPHENYLS)A group of organic compounds used in the manufacture of plastics and formerly used as a coolant in electric transformers. In the environment, PCBs are highly toxic to aquatic life. They persist in the environment for long periods of time and are biologically accumulative.
PEAK LOADThe highest electrical demand within a particular period of time. Daily electric peaks on weekdays occur in late afternoon and early evening. Annual peaks occur on hot summer days.
PEAK LOAD OR PEAK DEMANDThe electric load that corresponds to a maximum level of electric demand in a specified time period.
PEAK LOAD POWER PLANTA power generating station that is normally used to produce extra electricity during peak load times.
PEAKERA nickname for a power generating station that is normally used to produce extra electricity during peak load times.
PEAKING UNITA power generator used by a utility to produce extra electricity during peak load times.
PEATA heterogeneous mixture of partly decomposed organic matter that has accumulated in a water saturated environment over a very long period of time. Peat geologically is considered a very young form of coal and has a heating value of 6,600 Btu/pound in situ.
PERMThe measurement of water vapor through different materials measured in perminch (mass of water vapor moving through a unit area in unit time).
PETROCHEMICALSChemicals made from oil.
PETRODOLLARSMoney paid to other countries for oil imported to the United States.
PETROLEUMOil as found it its natural state under the ground.
PG&EThe acronym for Pacific Gas and Electric Company an electric and natural gas utility serving the central and northern California region.
PHOTOCELLA device that produces an electric reaction to visible radiant energy (light).
PHOTOSYNTHESISA process by which green plants change carbon dioxide into oxygen and organic materials. The energy for this process comes from sunlight.
PHOTOVOLTAIC CELLA semiconductor that converts light directly into electricity.
PIPELINEA line of pipe with pumping machinery and apparatus (including valves, compressor units, metering stations, regulator stations, etc.) for conveying a liquid or gas.
POOLCOPoolco refers to a specialized, centrally dispatched spot market power pool that functions as a shortterm market. It establishes the shortterm market clearing price and provides a system of longterm transmission compensation contracts. It is regulated to provide open access, comparable service and cost recovery. A poolco would make ancillary generation services, including load following, spinning reserve, backup power, and reactive power, available to all market participants on comparable terms. In addition, the Poolco provides settlement mechanisms when differences in contracted volumes exist between buyers and sellers of energy and capacity.
PORTFOLIO MANAGEMENTThe functions of resource planning and procurement under a traditional utility structure. Portfolio management can also be defined as the aggregation and management of a diverse portfolio of supply (and demandreduction) resources which will act as a hedge against various risks that may affect specific resources (i.e., fuel price fluctuations and certainty of supply, common mode failures, operational reliability, changes in environmental regulations, and the risk of health, safety, and environmental damages that may occur as a result of operating some supply resources). Under a more marketdriven power sector with a "powerpool" or POOLCO wholesale market structure, a portfolio manager would: aggregate and manage a diverse portfolio of spotmarket purchases, contractsfordifferences, futures contracts and other market
POWERElectricity for use as energy.
POWER AUTHORITIESQuasigovernmental agencies that perform all or some of the functions of a public utility.
POWER PLANT (Note: Two separate words, not one word.)A central station generating facility that produces energy.
POWER POOLTwo or more interconnected utilities that plan and operate to supply electricity in the most reliable, economical way to meet their combined load.
POWER POOLAn entity established to coordinate shortterm operations to maintain system stability and achieve leastcost dispatch. The dispatch provides backup supplies, shortterm excess sales, reactive power support, and spinning reserve. Historically, some of these services were provided on an unpriced basis as part of the members' utility franchise obligations. Coordinating shortterm operations includes the aggregation and firming of power from various generators, arranging exchanges between generators, and establishing (or enforcing) the rules of conduct for wholesale transactions. The pool may own, manage and/or operate the transmission lines ("wires") or be an independent entity that manages the transactions between entities. Often,the power pool is not meant to provide transmission access and pricing, or settlement mechanisms if differences between contracted volumes among buyers and sellers exist.
PPM (PARTS PER MILLION)The unit commonly used to represent the degree of pollutant concentration where the concentrations are small.
PREFERRED DAY-AHEAD SCHEDULEA Scheduling Coordinator's preferred schedule for the ISO dayahead scheduling process.
PREFERRED HOUR-AHEAD SCHEDULEA Scheduling Coordinator's preferred schedule for the ISO hourahead scheduling process.
PREFERRED SCHEDULEThe initial schedule produced by a Scheduling Coordinator that represents its preferred mix of generation to meet demand. The schedule includes the quantity of output (generators) and consumption (loads), details of any adjustment bids, and the location of each generator and load. The schedule also specifies the quantities and location of trades between the Scheduling Coordinator and all other Scheduling Coordinators, and is balanced with respect to generation, transmission losses, load, and trades.
PRESSURIZED WATER REACTOR (PWR)A nuclear power unit cooled by water that is pressurized to keep it from boiling when it reaches high temperatures.
PRIMARY FUELFuel consumed in the original production of energy, before conversion takes place.
PROGRAMMABLE CONTROLLERA device that controls the operation of electrical equipment (such as air conditioning units and lights) according to a preset time schedule.
PROPANEA gas that is both present in natural gas and refined from crude oil. It is used for heating, lighting and industrial applications. See also LPG.
PROVIDER OF LAST RESORTA legal obligation(traditionally given to utilities) to provide service to a customer where competitors have decided they do not want that customer's business.
PUBLIC ADVISERA appointee of the governor who attends all meetings of the California Energy Commission and provides assistance to members of the public and intervenors in cases before the Commission.
PUBLIC INTEREST GOALSPublic interest goals of electric utility regulation include: 1) interand intraclass and intergenerational equity); 2) the equal treatment of equals (horizontal equity); 3)balancing long and shortterm goals that have the potential to affect intergenerational balance; 4)protecting against the abuse of monopoly power; and 5) general protection of the health and welfare of the citizens of the state, nation, and world. Environmental and other types of social costs are subsumed under the equity and health and welfare responsibilities.
PUHCAThe Public Utility Holding Company Act of 1935. This act prohibits acquisition of any wholesale or retail electric business through a holding company unless that business forms part of an integrated public utility system when combined with the utility's other electric business. The legislation also restricts ownership of an electric business by nonutility corporations.
PUMPED HYDROELECTRIC STORAGECommercial method used for largescale storage of power. During offpeak times, excess power is used to pump water to a reservoir. During peak times, the reservoir releases water to operate hydroelectric generators.
PURPAThe Public Utility Regulatory Policy Act of 1978. Among other things, this federal legislation requires utilities to buy electric power from private "qualifying facilities," at an avoided cost rate. This avoided cost rate is equivalent to what it would have otherwise cost the utility to generate or purchase that power themselves. Utilities must further provide customers who choose to selfgenerate a reasonably priced backup supply of electricity.
PX GENERATIONGeneration being scheduled by the PX.
PX LOADLoad that has been scheduled by the PX, and which is received through the use of transmission or distribution facilities owned by participating transmission owners.
PX PARTICIPANTAn entity that is authorized to buy or sell energy or ancillary services through the PX, and any agent authorized to act on behalf of such an entity.
QUADOne quadrillion (1015 or 1,000,000,000,000,000) British thermal units (Btus). An amount of energy equal to 170 million barrels of oil. Total U.S. consumption of all forms of energy is (in the 1990s) about 83 quads in an average year.
QUALIFYING FACILITYQFs are nonutility power producers that often generate electricity using renewable and alternative resources, such as hydro, wind, solar, geothermal or biomass (solid waste). QFs must meet certain operating, efficiency, and fueluse standards set forth by the Federal Energy Regulatory Commission (FERC). If they meet these FERC standards, utilities must buy power from them. QFs usually have longterm contracts with utilities for the purchase of this power, which is among the utility's highestpriced resources.
QUALIFYING FACILITYA cogenerator or small power producer which under federal law, has the right to sell its excess power output to the public utility.
QUALIFYING FACILITY (QF)Under PURPA, QFs were allowed to sell their electric output to the local utility at avoided cost rates. To become a QF, the independent power supplier had to produce electricity with a specified fuel type (cogeneration or renewables), and meet certain ownership, size, and efficiency criteria established by the Federal Energy Regulatory Commission.
R-VALUEA unit of thermal resistance used for comparing insulating values of different material. It is basically a measure of the effectiveness of insulation in stopping heat flow. The higher the Rvalue number, a material, the greater its insulating properties and the slower the heat flow through it. The specific value needed to insulate a home depends on climate, type of heating system and other factors.
RADA unit of measure of absorbed radiation. Acronym for radiation absorbed dose. One rad equals 100 ergs of radiation energy per gram of absorbing material.
RADIANT BARRIERA device designed to reduce or stop the flow of radiant energy.
RADIANT ENERGYEnergy transferred by the exchange of electromagnetic waves from a hot or warm object to one that is cold or cooler. Direct contact with the object is not necessary for the heat transfer to occur.
RADIATIONThe flow of energy across open space via electromagnetic waves such as light. Passage of heat from one object to another without warming the air space in between.
RANKINE CYCLEThe steamRankine cycle employing steam turbines has been the mainstay of utility thermal electric power generation for many years. The cycle, as developed over the years uses superheat, reheat and regeneration. Modern steam Rankine systems operate at a cycle top temperature of about 1,073 degrees Celsius with efficiencies of about 40 percent.
RATE-BASINGrefers to practice by utilities of allotting funds invested in utility Research Development Demonstration and Commercialization and other programs from ratepayers, as opposed to allocating these costs to shareholders.
RAW FUEL Coal, natural gas, wood or other fuel that is used in the form in which it is found in nature, without chemical processing. 
RDF (REFUSE DERIVED FUEL)The fuel component of municipal solid waste (MSW), which is the byproduct of shredding MSW to a uniform size, screening out oversized materials and isolating ferrous material in magnetic separation. The resulting RDF can be burned as a fuel source.
REACTORA device in which a controlled nuclear chain reaction can be maintained, producing heat energy.
REAL-TIME MARKETThe competitive generation market controlled and coordinated by the ISO for arranging realtime imbalance energy.
REAL-TIME PRICINGThe instantaneous pricing of electricity based on the cost of the electricity available for use at the time the electricity is demanded by the customer.
RECLAIMED OILLubricating oil that is processed to be used over again.
RECOVERED ENERGYReused heat or energy that otherwise would be lost. For example, a combined cycle power plant recaptures some of its own waste heat and reuses it to make extra electric power.
RECOVERY EFFICIENCY(Thermal efficiency) Ia water heater, a measure of the percentage of heat from the combustion of gas which is transferred to the water as measured under specified test conditions.
REFINERmeans any person who owns, operates, or controls the operations of one or more refineries.
REFINERYA facility that separates crude oil into varied oil products. The refinery uses progressive temperature changes to separate by vaporizing the chemical components of crude oil that have different boiling points. These are distilled into usable products such as gasoline, fuel oil, lubricants and kerosene.
REFORMULATED GASOLINE (RFG)A cleanerburning gasoline that has had its compositions and/or characteristics altered to reduce vehicular emissions of pollutants. It was sold in California beginning in 1996 with the oxygenate additive MTBE.
REFRIGERANTA fluid such as freon that is used in cooling devices to absorb heat from surrounding air or liquids as it evaporates.
REGULATIONThe service provided by generating units equipped and operating with automatic generation controls that enables the units to respond to the ISO's direct digital control signals to match realtime demand and resources, consistent with establsihed operating criteria.
REGULATORY MUST-RUN GENERATIONUtilities will be allowed to generate electricity when hydro resources are spilled for fish releases, irrigation, and agricultural purposes, and to generate power that is required by federal or state laws, regulations, or jurisdictional authorities. Such requirements include hydrological flow requirements, irrigation and water supply, solidwaste generation, or other generation contracts in effect on December 20, 1995.
REGULATORY MUST-TAKE GENERATIONUtilities will be allowed to generate electricity from those resources identified by the CPUC
REHEATThe heating of air that has been previously cooled either by mechanical refrigeration or economizer cooling systems.
REID VAPOR PRESSURE (RVP)a standard measurement of a liquid's vapor pressure in pounds per square inch at 100 degrees Fahrenheit. It is an indication of the propensity of the liquid to evaporate.
REID VAPOR PRESSURE (RVP)a standard measurement of a liquid's vapor pressure in pounds per square inch at 100 degrees Fahrenheit. It is an indication of the propensity of the liquid to evaporate.
RELIABILITYElectric system reliability has two components adequacy and security. Adequacy is the ability of the electric system to supply the aggregate electrical demand and energy requirements of the customers at all times, taking into account scheduled and unscheduled outages of system facilities. Security is the ability of the electric system to withstand sudden disturbances such as electric short circuits or unanticipated loss of system facilities.
RELIABILITY MUST-RUN GENERATIONThe ISO will allow utilities to generate power that is needed to ensure system reliability. This includes generation:Required to meet the reliability criteria for interconnected systems operation.Needed to meet load (demand) in constrained areas.Needed to provide voltage or security support of the ISO or of a local area.
RENEWABLE ENERGYResources that constantly renew themselves or that are regarded as practically inexhaustible. These include solar, wind, geothermal, hydro and wood. Although particular geothermal formations can be depleted, the natural heat in the earth is a virtually inexhaustible reserve of potential energy. Renewable resources also include some experimental or lessdeveloped sources such as tidal power, sea currents and ocean thermal gradients.
RENEWABLE RESOURCESRenewable energy resources are naturally replenishable, but flowlimited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Some (such as geothermal and biomass) may be stocklimited in that stocks are depleted by use, but on a time scale of decades, or perhaps centuries, they can probably be replenished. Renewable energy resources include: biomass, hydro, geothermal, solar and wind. In the future they could also include the use of ocean thermal, wave, and tidal action technologies. Utility renewable resource applications include bulk electricity generation, onsite electricity generation, distributed electricity generation, nongrid
REREGULATIONThe design and implementation of regulatory practices to be applied to the remaining regulated entities after restructuring of the verticallyintegrated electric utility. The remaining regulated entities would be those that continue to exhibit characteristics of a natural monopoly, where imperfections in the market prevent the realization of more competitive results,and where, in light of other policy considerations, competitive results are unsatisfactory in one or more respects. Reregulation could employ the same or different regulatory practices as those used before restructuring.
RESEARCH AND DEVELOPMENT (R&D)Research is the discovery of fundamental new knowledge. Development is the application of new knowledge to develop a potential new service or product. Basic power sector R&D is most commonly funded and conducted through the Department of Energy (DOE), its associated government laboratories, university laboratories,the Electric Power Research Institute (EPRI), and private sector companies.
RESERVEThe extra generating capability that an electric utility needs, above and beyond the highest demand level it is required to supply to meet its users¼ needs.
RESERVE GENERATING CAPACITYThe amount of power that can be produced at a given point in time by generating units that are kept available in case of special need. This capacity may be used when unusually high power demand occurs, or when other generating units are offline for maintenance, repair or refueling.
RESERVE MARGINThe differences between the dependable capacity of a utility's system and the anticipated peak load for a specified period.
RESIDENTIAL BUILDINGmeans any hotel, motel, apartment house, lodging house, single and dwelling, or other residential building which is heated or mechanically cooled.
RESIDUEany organic matter left as residue, such as agricultural and forestry residue, including, but not limited to, conifer thinnings, dead and dying trees, commercial hardwood, noncommercial hardwoods and softwoods, chaparral, burn, mill, agricultural field, and industrial residues, and manure.
RESISTANCE (ELECTRICAL)The ability of all conductors of electricity to resist the flow of current, turning some of it into heat. Resistance depends on the cross section of the conductor (the smaller the cross section, the greater the resistance) and its temperature (the hotter the cross section, the greater its resistance).
RESISTANCE (THERMAL)The reciprocal of thermal conductance. See RVALUE.
RESOURCE EFFICIENCYThe use of smaller amounts of physical resources to produce the same product or service. Resource efficiency involves a concern for the use of all physical resource sand materials used in the production and use cycle, not just the energy input.
RESTRUCTURINGThe reconfiguration of the verticallyintegrated electric utility. Restructuring usually refers to separation of the various utility functions into individuallyoperated and owned entities.
RETAIL COMPETITIONA system under which more than one electric provider can sell to retail customers, and retail customers are allowed to buy from more than one provider. (See also direct access)
RETAIL MARKETA market in which electricity and other energy services are sold directly to the enduse customer.
RETORTINGThe heating of oil shale to get the oil out from it.
RETROFITbroad term that applies to any change after the original purchase, such as adding equipment not a part of the original purchase. As applied to alternative fuel vehicles, it refers to conversion devices or kits for conventional fuel vehicles. (Same as „aftermarket¾.)
RTGA Regional Transmission Group. A voluntary organization of transmission owners,users, and other entities interested in coordinating transmission planning, expansion, operation,and use on a regional and interregional basis. Such groups are subject to FERC approval.
RULES OF CONDUCTRules set in advance to delineate acceptable activities by participants,particularly participants with significant market power.
RURAL ELECTRIC COOPERATIVEA nonprofit, customerowned electric utility that distributes power in a rural area.
SAE VISCOSITY NUMBERA system established by the Society of Automotive Engineers for classifying crankcase oils and automotive transmission and differential lubricants according to their viscosities.
SE (Seasonal Efficiency)a measure of the percentage of heat from the combustion of gas and from associated electrical equipment which is transferred to the space being heated during a year under specified conditions.
SECOND GENERATION BIOFUELSSecond generation biofuels are derived from lignocellulosic crops. Plants are made from lignin and cellulose, second generation technology allows these two components of a plant to be split. Then the cellulose can be fermented into alcohol in much the same way as a first generation biofuel. These biofuels can be manufactured from various types of biomass. Biomass is a wide-ranging term meaning any source of organic carbon that is renewed rapidly as part of the carbon cycle. Biomass is all derived from plant materials but can also include animal materials.
SECURITIZEThe aggregation of contracts for the purchase of the power output from various energy projects into one pool which then offers shares for sale in the investment market. This strategy diversifies project risks from what they would be if each project were financed individually, thereby reducing the cost of financing. Fannie Mae performs such a function in the home mortgage market.
SEER (Seasonal Energy Efficiency Ratio)The total cooling output of a central air conditioning unit in Btus during its normal usage period for cooling divided by the total electrical energy input in watthours during the same period, as determined using specified federal test procedures.
SEER (Seasonal Energy Efficiency Ratio)the total cooling output of a central air conditioning unit in Btus during its normal usage period for cooling divided by the total electrical energy input in watthours during the same period, as determined using specified federal test procedures. (Title 20, Section 21602(c)(11).
SELF-GENERATIONA generation facility dedicated to serving a particular retail customer,usually located on the customer's premises. The facility may either be owned directly by the retail customer or owned by a third party with a contractual arrangement to provide electricity to meet some or all of the customer's load.
SELF-SERVICE WHEELINGPrimarily an accounting policy comparable to netbilling or running the meter backwards. An entity owns generation that produces excess electricity at one site, that is used at another site(s) owned by the same entity. It is given billing credit for the excess electricity (displacing retail electricity costs minus wheeling charges) on the bills for its other sites.
SENSIBLE HEATHeat that results in a temperature change.
SERVICE AREAThe geographical territory served by a utility.
SERVICE AREAany contiguous geographic area serviced by the same electric utility.
SET POINTScheduled operating level for each generating unit or other resource scheduled to run in the Hourahead Schedule.
SETTLEMENTThe process of financial settlement for products and services purchased and sold. Each settlement involves a price and quantity. Both the ISO and PX may perform settlement functions.
SHADE SCREENA screen affixed to the exterior of a window or other glazed opening, designed to reduce the solar radiation reaching the glazing.
SHADING1) The protection from heat gains due to direct solar radiation; 2) Shading is provided by (a) permanently attached exterior devices, glazing materials, adherent materials applied to the glazing, or an adjacent building for nonresidential buildings, hotels, motels and highrise apartments, and by (b) devices affixed to the structure for residential buildings.
SHADING COEFFICIENTthe ratio of solar heat gain through a specific glazing system to the total solar heat gain through a single layer of clear, doublestrength glass.
SIDE FINSVertical shading elements mounted on either side of a glazed opening that blocks direct solar radiation from the lower, lateral portions of the sun's path. SITE any location on which a facility is constructed or is proposed to be constructed.
SITE ENERGYThe energy consumed at a building location or other enduse site.
SKY TEMPERATUREThe equivalent temperature of the clouds, water vapor, and other atmospheric elements that make up the sky to which a surface can radiate heat.
SKYLIGHTAny opening in the roof surface which is glazed with a transparent or translucent material.
SMOGOriginally "smog" meant a mixture of smoke and fog. The definition has expanded to mean air that has restricted visibility due to pollution. Pollution formed in the presence of sunlight is called photochemical smog. According to the U.S. EPA, smog is "a mixture of pollutants, principally groundlevel ozone, produced by chemical reactions in the air involving smogforming chemicals. A major portion of smogformers come from burning of petroleumbased fuels such as gasoline. Other smogformers, volatile organic compounds, are found in products such as paints and solvents. Smog can harm health, damage the environment and cause poor visibility. Major smog occurrences are often linked to heavy motor vehicle traffic, sunshine, high temperatures and calm winds or temperature inversion (weather condition in which warm air is trapped close to the ground instead of rising). Smog is often worse away from the source of the smog
SOLAR CELLA photovoltaic cell that can convert light directly into electricity. A typical solar cell uses semiconductors made from silicon.
SOLAR COLLECTORA component of an active or passive solar system that absorbs solar radiation to heat a transfer medium which, in turn, supplies heat energy to the space or water heating system.
SOLAR COLLECTORA surface or device that absorbs solar heat and transfers it to a fluid. The heated fluid then is used to move the heat energy to where it will be useful, such as in water or space heating equipment.
SOLAR ENERGYHeat and light radiated from the sun.
SOLAR ENERGY RESEARCH INSTITUTE (SERI)Established in 1974 and funded by the federal government, the institute's general purpose is to support U.S. Department of Energy's solar energy program and foster the widespread use of all aspects of solar technology, including photovoltaics, solar heating and cooling, solar thermal power generation, wind ocean thermal conversion and biomass conversion.
SOLAR HEAT GAINHeat added to a space due to transmitted and absorbed solar energy.
SOLAR HEAT GAIN FACTORAn estimate used in calculating cooling loads of the heat gain due to transmitted and absorbed solar energy through 1/8"thick, clear glass at a specific latitude, time and orientation.
SOLAR HEATING AND HOT WATER SYSTEMSSolar heating or hot water systems provide two basic functions: (a) capturing the sun's radiant energy, converting it into heat energy, and storing this heat in insulated storage tank(s); and (b) delivering the stored energy as needed to either the domestic hot water or heating system. These components are called the collection and delivery subsystems.
SOLAR IRRADIATIONThe amount of radiation, both direct and diffuse, that can be received at any given location.
SOLAR POWERElectricity generated from solar radiation.
SOLAR RADIATIONElectromagnetic radiation emitted by the sun.
SOLAR SATELLITE POWERA proposed process of using satellites in geosynchronous orbit above the earth to capture solar energy with photovoltaic cells, convert it to microwave energy, beam the microwaves to earth where they would be received by large antennas, and changed from microwave into usable electricity.
SOLAR THERMALThe process of concentrating sunlight on a relatively small area to create the high temperatures needs to vaporize water or other fluids to drive a turbine for generation of electric power.
SOLAR THERMAL POWER PLANTmeans a thermal powerplant in which 75 percent or more of the total energy output is from solar energy and the use of backup fuels, such as oil, natural gas, and coal, does not, in the aggregate, exceed 25 percent of the total energy input of the facility during any calendar year period.
SOURCE ENERGYAll the energy used in delivering energy to a site, including power generation and transmission and distribution losses, to perform a specific function, such as space conditioning, lighting, or water heating. Approximately three watts (or 10.239 Btus) of energy is consumed to deliver one watt of usable electricity.
SPECIAL CONTRACTSAny contract that provides a utility service under terms and conditions other than those listed in the utility's tariffs. For example, an electric utility may enter into an agreement with a large customer to provide electricity at a rate below the tariffed rate in order to prevent the customer from taking advantage of some other option that would result in the loss of the customer's load. This generally allows that customer to compete more effectively in their product market.
SPECIFIC HEATIn English units, the quantity of heat, in Btu, needed to raise the temperature of one pound of material one degree Fahrenheit.
SPLIT-THE-SAVINGSThe basis for settling economyenergy transactions between utilities. The added costs of the supplier are subtracted from the avoided costs of the buyer, and the difference is evenly divided.
STANDBY LOSSA measure of the losses from a water heater tank. When expressed as a percentage, standby loss is the ratio of heat loss per hour to the heat content of the stored water above room temperature. When expressed in watts, standby loss is the heat lost per hour, per square foot of tank surface area.
STEADY STATE EFFICIENCYA performance rating for space heaters; a measure of the percentage of heat from combustion of gas which is transferred to the space being heated under specified steady state conditions.
STEAM ELECTRIC PLANTA power station in which steam is used to turn the turbines that generate electricity. The heat used to make the steam may come from burning fossil fuel, using a controlled nuclear reaction, concentrating the sun's energy, tapping the earth's natural heat or capturing industrial waste heat.
STIRLING ENGINEAn external combustion engine that converts heat into useable mechanical energy (shaftwork) by the heating (expanding) and cooling (contracting) of a captive gas such as helium or hydrogen.
STORAGE TYPE WATER HEATERA water heater that heats and stores water at a thermostatically controlled temperature for delivery on demand.
STRANDED BENEFITSPublic interest programs and goals which could be compromised or abandoned by a restructured electric industry. These potential "stranded benefits" might include: environmental protection, fuel diversity, energy efficiency, lowincome ratepayer assistance, and other types of socially beneficial programs.
STRANDED COSTS/STRANDED ASSETSSee embedded Costs Exceeding Market Prices.
STRATEGIC PETROLEUM RESERVEThe strategic petroleum reserve consists of government owned and controlled crude oil stockpiles stored at various locations in the Gulf Coast region of the country. These reserves can be drawn down in response to sever oil supply disruptions. The target is to have a reserve of 750 million barrels of oil. Use of the reserve must be authorized by the President of the United States.
SUBSTATIONA facility that steps up or steps down the voltage in utility power lines. Voltage is stepped up where power is sent through longdistance transmission lines. it is stepped down where the power is to enter local distribution lines.
SUNK COSTIn economics, a sunk cost is a cost that has already been incurred, and therefore cannot be avoided by any strategy going forward.
SUPERCONDUCTORA synthetic material that has very low or no electrical resistance. Such experimental materials are being investigated in laboratories to see if they can be created at near room temperatures. If such a superconductor can be found, electrical transmission lines with no little or no resistance may be built, thus conserving energy usually lost in transmission. Superconductors could also have uses in computer chips, solid state devices and electrical motors or generators.
SUPERTANDKERA very large ship designed to transport more than 500,000 deadweight tonnage of oil.
SUPPLY-SIDEActivities conducted on the utility's side of the customer meter. Activities designed to supply electric power to customers, rather than meeting load though energy efficiency measures or onsite generation on the customer side of the meter.
SUPPLY BIDA bid into the PX indicating a price at which a seller is prepared to sell energy or ancillary services.
SURPLUS(Electric utility) Excess firm energy available from a utility or region for which there is no market at the established rates.
SUSTAINED ORDERLY DEVELOPMENTA condition in which a growing and stable market is identified by orders that are placed on a reliable schedule. The orders increase in magnitude as previous deliveries and engineering and field experience lead to further reductions in costs. The reliability of these orders can be projected many years into the future, on the basis of longterm contracts, to minimize market risks and investor exposure. (See also "Commercialization.")
SYNCRUDESynthetic crude oil made from coal of from oil shale.
SYNFUELSynthetic gas or synthetic oil. Fuel that is artificially made as contrasted to that which is found in nature. Synthetic gas made from coal is considered to be more economical and easier to produce than synthetic oil. When natural gas supplies in the earth are being depleted, it is expected that synthetic gas will be able to be used widely as a substitute fuel.
SYNGASSynthetic gas make from coal.
SYSTEMA combination of equipment and/or controls, accessories, interconnecting means and terminal elements by which energy is transformed to perform a specific function, such as climate control, service water heating, or lighting.
SYSTEM INTEGRATION (OF NEW TECHNOLOGIES)The successful integration of a new technology into the electric utility system by analyzing the technology's system effects and resolving any negative impacts that might result from its broader use.
TAKE-OUT-POINTThe metering points at which a metered entity takes delivery of energy.
TAKINGReducing the value of someone's property through government action without just compensation.
TAME (TERTIARY AMYL METHYL ETHER)another oxygenate that can be used in reformulated gasoline. It is an ether based on reactive C5 olefins and methanol.
TAR SANDSSedimentary rocks containing heavy oil that cannot be extracted by conventional petroleum recovery methods.
TARIFFA document, approved by the responsible regulatory agency,listing the terms and conditions, including a schedule of prices, under which utility services will be provided.
TAX CREDITSCredits established by the federal and state government to assist the development of the alternative energy industry.
TEMPERATUREDegree of hotness or coldness measured on one of several arbitrary scales based on some observable phenomenon (such as the expansion).
THERMOne hundred thousand (100,000) British thermal units (1 therm = 100,000 Btu).
THERMAL BREAK (thermal barrier)An element of low heat conductivity placed in such a way as to reduce or prevent the flow of heat. Some metal framed windows are designed with thermal breaks to improve their overall thermal performance.
THERMAL MASSA material used to store heat, thereby slowing the temperature variation within a space. Typical thermal mass materials include concrete, brick, masonry, tile and mortar, water, and rock or other materials with high heat capacity.
THERMAL POWER PLANTany stationary or floating electrical generating facility using any source of thermal energy, with a generating capacity of 50 megawatts or more, and any facilities appurtenant thereto. Exploratory, development, and production wells, resource transmission lines, and other related facilities used in connection with a geothermal exploratory project or a geothermal field development project are not appurtenant facilities for the purposes of this division. Thermal powerplant does not include any wind, hydroelectric, or solar photovoltaic electrical generating facility.
THERMAL (ENERGY) STORAGEA technology that lowers the amount of electricity needed for comfort conditioning during utility peak load periods. A buildings thermal energy storage system might, for example, use offpeak power to make ice or to chill water at night, later using the ice or chilled water in a power saving process for cooling during the day. See THERMAL MASS.
THERMALLY ENHANCED OIL RECOVERY (TEOR)Injection of steam to increase the amount of petroleum that may be recovered from a well.
THERMODYNAMICSA study of the transformation of energy into other manifested forms and of their practical applications. The three laws of thermodynamics are:1. Law of Conservation of Energy 2. Heat cannot be changed directly into work at constant temperature by a cyclic process3. Heat capacity and entropy of every crystalline solid becomes zero at absolute zero (0 degrees Kelvin)
THERMOSTATAn automatic control device designed to be responsive to temperature and typically used to maintain set temperatures by cycling the HVAC system.
THERMOSTAT, SETBACKA device, containing a clock mechanism, which can automatically change the inside temperature maintained by the HVAC system according to a preset schedule. The heating or cooling requirements can be reduced when a building is unoccupied or when occupants are asleep.
TIDAL POWEREnergy obtained by using the motion of the tides to run water turbines that drive electric generators.
TIME-OF-USE METERA measuring device that records the times during which a customer uses various amounts of electricity. This type of meter is used for customers who pay timeofuse rates.
TIME-OF-USE RATESElectricity prices that vary depending on the time periods in which the energy is consumed. In a timeof use rate structure, higher prices are charged during utility peak
TIME-OF-USE (TOU) RATESThe pricing of electricity based on the estimated cost of electricity during a particular time block. Timeofuse rates are usually divided into three or four time blocks per twenty
TON OF COOLINGA useful cooling effect equal to 12,000 Btu hours.
TRADING DAYThe 24hour period beginning at midnight and ending at the following midnight.
TRANSFER (Electric utility)To move electric energy from one utility system to another over transmission lines.
TRANSFORMERA device, which through electromagnetic induction but without the use of moving parts, transforms alternating or intermittent electric energy in one circuit into energy of similar type in another circuit, commonly with altered values of voltage and current.
TRANSITION COSTSSee Embedded Costs Exceeding Market Prices.
TRANSMISSIONTransporting bulk power over long distances.
TRANSMISSION-DEPENDENT UTILITYA utility that relies on its neighboring utilities to transmit to it the power it buys from its suppliers. A utility without its own generation sources, dependent on another utility's transmission system to get its purchased power supplies.
TRANSMISSION OWNERAn entity that owns transmission facilities or has firm contractual right to use transmission facilities.
TRANSMITTANCEThe time rate of heat flow per unit area under steady conditions from the air (or other fluid) on the warm side of a barrier to the air (or fluid) on the cool side, per unit temperature difference between the two sides.
TRANSMITTING UTILITY (TRANSCO)This is a regulated entity which owns, and may construct and maintain, wires used to transmit wholesale power. It may or may not handle the power dispatch and coordination functions. It is regulated to provide nondiscriminatory connections,comparable service and cost recovery. According to EPAct, any electric utility, qualifying cogeneration facility, qualifying small power production facility, or Federal power marketing agency which owns or operates electric power transmission facilities which are used for the sale of electric energy at wholesale. (See also "Generation Dispatch & Control" and "PowerPool.")
TURBINE GENERATORA device that uses steam, heated gases, water flow or wind to cause spinning motion that activates electromagnetic forces and generates electricity.
U value or Ufactor A measure of how well heat is transferred by the entire window the frame, sash and glass either into or out of the building. U
UAA measure of the amount of heat that would be transferred through a given surface or enclosure (such as a building envelope) with a one degree Fahrenheit temperature difference between the two sides. The UA is calculated by multiplying the UValue by the area of the surface (or surfaces).
UDCUtility distribution company. An entity that owns a distribution system for the delivery of energy to and from the ISOcontrolled grid, and that provides regulated, retail service to eligible enduse customers who are not yet eligible for direct access, or who choose not to arrange services through another retailer.
ULTRAHIGH VOLTAGE TRANSMISSIONTransporting electricity over bulkpower lines at voltages greater than 800 kilovolts.
UNBUNDLINGDisaggregating electric utility service into its basic components and offering each component separately for sale with separate rates for each component. For example, generation, transmission and distribution could be unbundled and offered as discrete services.
UNCONDITIONED SPACEA space that is neither directly nor indirectly conditioned space, which can be isolated from conditioned space by partitions and/or closeable doors.
UNIVERSAL SERVICEElectric service sufficient for basic needs (an evolving bundle of basic services) available to virtually all members of the population regardless of income.
UNLEADED GASOLINEGasoline that has had tetraethyl lead removed in conformance with federal and state regulations.
UPGRADE (Electric utility)Replacement or addition of electrical equipment resulting in increased generation or transmission capability.
UPRATE (Electric utility)An increase in the rating or stated measure of generation or transfer capability.
UPSTREAMA term used in the petroleum industry referring to the exploration and production side of the business. This includes pipelines but production before reaching the refinery.
URANIUMA radioactive element, found in ores, of which atoms can be split to create energy.
URANIUM ENRICHMENTThe process of increasing the percentage of pure uranium above the levels found in naturally occurring uranium ore, so that it may be used as fuel.
UTILITYA regulated entity which exhibits the characteristics of a natural monopoly. For the purposes of electric industry restructuring, "utility" refers to the regulated, verticallyintegrated electric company. "Transmission utility" refers to the regulated owner/operator of the transmission system only. "Distribution utility" refers to the regulated owner/operator of the distribution system which serves retail customers.
VAPOR BARRIERA material with a permeance of one perm or less which provides resistance to the transmission of water vapor.
VAV System (Variable Air Volume System)A mechanical HVAC system capable of serving multiple zones which controls the temperature maintained in a zone by controlling the amount of heated or cooled air supplied to the zone.
VENTILATIONThe process of supplying or removing air by natural or mechanical means to or from any space. Such air may or may not have been conditioned or treated.
VERTICAL INTEGRATIONAn arrangement whereby the same company owns all the different aspects of making, selling, and delivering a product or service. In the electric industry, it refers to the historically common arrangement whereby a utility would own its own generating plants,transmission system, and distribution lines to provide all aspects of electric service.
VISIBLE LIGHT TRANSMITTANCEThe ratio of visible light transmitted through a substance to the total visible light incident on its surface.
VOLTA unit of electromotive force. It is the amount of force required to drive a steady current of one ampere through a resistance of one ohm. Electrical systems of most homes and office have 120 volts.
VOLTAGE OF A CIRCUIT (Electric utility)The electric pressure of a circuit, measured in volts. Usually a nominal rating, based on the maximum normal effective difference of potential between any two conductors of the circuit.
VOLUMETRIC WIRES CHARGEA type of charge for using the transmission and/or distribution system that is based on the volume of electricity that is transmitted.
WARRANTYA seller's guarantee to purchaser that product is what it is represented to be and, if it is not, that it will be repaired or replaced. Within the context of vehicles, refers to an engine manufacturer's guarantee that the engine will meet "certified" engine standards at 50,000 miles or the engine will be replaced. Retrofits may generally void an engine warranty.
WATER HEATERAn appliance for supplying hot water for purposes other than space heating or pool heating.
WATSCOThe Western Association for Transmission System Coordination.
WATTA unit of measure of electric power at a point in time, as capacity or demand.
WATT-HOUROne watt of power expended for one hour.
WEATHERSTRIPPINGSpecially designed strips, seals and gaskets installed around doors and windows to limit air leakage.
WET-BULB TEMPERATUREThe temperature at which water, by evaporating into air, can bring the air to saturation at the same temperature. Wetbulb temperature is measured by a wetbulb psychrometer.
WHEELINGThe transmission of electricity by an entity that does not own or directly use the power it is transmitting. Wholesale wheeling is used to indicate bulk transactions in the wholesale market, whereas retail wheeling allows power producers direct access to retail customers. This term is often used colloquially as meaning transmission.
WHEELINGUsing a utility's lines to transport power from one neighboring system to another.
WHOLE HOUSE FANA system capable of cooling a house by exhausting a large volume of warm air when the outside air is cool.
WHOLESALE COMPETITIONA system whereby a distributor of power would have the option to buy its power from a variety of power producers, and the power producers would be able to compete to sell their power to a variety of distribution companies.
WHOLESALE POWER MARKETThe purchase and sale of electricity from generators to resellers (who sell to retail customers) along with the ancillary services needed to maintain reliability and power quality at the transmission level.
WHOLESALE TRANSMISSION SERVICESThe transmission of electric energy sold, or to be sold, at wholesale in interstate commerce (from EPAct).
WIRES CHARGEA broad term which refers to charges levied on power suppliers or their customers for the use of the transmission or distribution wires.
WRTAThe Western Regional Transmission Association, an RTG.
WSSPThe Western Systems Power Pool. A FERC approved industry institution that provides a forum for shortterm trades in electric energy, capacity, exchanges and transmission services. The pool consists of approximately 50 members and serves 22 states, a Canadian province and 60 million people. The WSSP is headquarter in Phoenix, Arizona.
X-RAYA type of electromagnetic radiation having low energy levels.
XENONA heavy gas used in specialized electric lamps.
XYLOID COALBrown coal or lignite mostly derived from wood.