Glossary of Electric Utility Industry Terms

Industry insiders often use terms that are confusing and difficult to understand. We hope you find the following words and corresponding definitions helpful.



access charge: A fee levied for access to a utility's transmission or distribution system. It is a charge for the right to send electricity over another's wires and is not typically tied to the actual amount of power shipped.

acre-feet: The amount of water it takes to cover one acre to a depth of one foot. This measure is used to describe the quantity of storage in a reservoir or hydro system.

administrator: The administrator of the Bonneville Power Administration (BPA). Under BPA's new corporate structure, the administrator's title is chief executive officer (CEO).

advance energy: Energy delivered at BPA's option to its Direct Service Industrial customers in lieu of restricting power at times when reservoirs are on a fixed operation. The energy is subject to return if BPA determines that firm commitments cannot be met because of advance energy deliveries.

aggregators: Brokers who seek to bring together customers to create a "load" so that they can buy power in bulk, making a profit on the sale.

alternating current (AC): An electric current that reverses direction of flow at regular intervals and has alternately positive and negative values.

anadromous fish: Fish (such as salmon and steelhead) that hatch in freshwater, migrate to the ocean, mature there, and return to freshwater to spawn.

ancillary services: Includes the provision of reactive power, frequency control and load following.

automatic generation control (AGC): Regulation of the power output of electric generators within a control area in response to changes in load, system frequency and other factors, to maintain the scheduled system frequency and interchanges with other control areas.

average annual megawatt or average megawatt (aMW): A unit of energy output over a year that is equal to the energy produced by the continuous operation of one megawatt of capacity over a period of time. (Equal to 8,760 megawatt-hours).

average cost pricing: A pricing mechanism based on dividing the total cost of providing electricity incurred in a period by the number of units sold in the same period.

average system cost (ASC): The cost of a utility's generation and transmission system. Under the Residential Exchange provisions of the Northwest Power Act, a utility may sell power to BPA at the utility's average system cost and purchase the same amount of power back from BPA at a rate based on the costs of the Federal Base System.

avoided cost: A guideline for comparing the value of conservation and renewable resources with other resources. Literally, the cost a utility avoids by purchasing a conservation or renewable resource versus acquiring energy elsewhere.

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baseload: A power plant that is planned to run continually except for maintenance and scheduled or unscheduled outages. Baseload also refers to the minimum load in a power system over a given period of time.

billing credit: BPA payments to its utility customers (either in the form of cash or offsets against billing) for actions taken to reduce BPA's obligation to acquire new resources under the provisions of the Northwest Power Act. Customer actions may include the development of independent conservation programs or new generation resources.

biomass conversion: The process by which organic materials, such as wood waste or garbage, are burned for direct energy or electrical generation, or by which these materials are converted to synthetic natural gas.

blackout: The disconnection of the source of electricity serving an area brought about by an emergency forced outage or other fault in the generation, transmission or distribution system.

British thermal unit (BTU): The amount of heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit (3,412 BTUs are equal to one kilowatt-hour).

brownout: The partial reduction of electrical voltages. A brownout results in lights dimming and motor-driven devices slowing down.

bypass system: Structure in a dam that routes fish around rather than through the turbines.

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capability: The maximum load that a machine, station or system can carry under specified conditions for a given interval without exceeding approved limits.

capacity: The maximum power that can be produced by a generating resource at specified times under specified conditions.

captive customers: Any customer that cannot readily purchase power from suppliers other than the local utility, even if they have the legal right to do so. Captive electricity customers are generally considered to be the residential and small commercial customers.

cogeneration: The production of heat and electricity from a common fuel source.

combined cycle: The combination of a gas turbine and steam turbine in an electric generating plant. The waste heat from the first turbine cycle provides the heat energy for the second turbine cycle.

combustion turbine: A fuel-fired turbine engine used to drive an electric generator.

comparability tariffs: In a restructured wholesale electrical market, according to FERC Order 888, there should be non-discriminatory, open access charges or tariffs for use of the transmission network by all generators of wholesale electricity on a comparable basis. These tariffs provide that the same prices, terms and conditions would apply to both the utility for its own transactions and to other generators.

competition transition charge: A mechanism to assure fairness and stability for existing utilities as we shift to a new market structure. The net effect of CTC will fall on customers who change suppliers during the Transition Phase. The purpose is to avoid cost-shifting, and to enable utilities to retire debt and compete fairly.

conductor: The wire cable strung between transmission towers or distribution poles through which current flows.

conservation: A resource produced by increasing the efficiency of energy use, production or distribution.

cooperative (co-op): A private non-profit utility owned by its members and essentially self-regulated by an elected board of directors.

coordinated operation: The operation of two or more interconnected electrical systems or a group of hydro plants to achieve greater reliability and economy.

cost-based ratemaking: Regulated rates based on costs expended, not on meeting performance objectives identified by management.

cost of service analysis: A study designed to determine the cost of providing service to various classes of customers; used as a basis for establishing power and transmission rates.

cost shifting: Shifting cost increases or decreases to classes of customers, e.g., to residential from industrial or to commercial from residential.

critical period: The portion of the historical 50-year streamflow record that would product the least amount of energy; that period is currently the 42 ½ months of water conditions from August 16, 1928 through February 1932. The critical period is used to determine the maximum firm load-carrying capability of the present system under "worst-case" conditions.

critical rule curve: A graphic representation of the storage level of a reservoir at various times of the year under critical streamflow conditions. The curve serves as a guide to the use of stored water by indicating the level at which storage would become insufficient to meet firm energy loads.

critical water: A sequence of streamflows under which the regional hydro system could produce an amount of power equal to that which could have been produced during the historical critical period given today's generating facilities and constraints.

cubic feet per second (cfs): A measurement of water flow representing one cubic foot of water moving past a given point in one second.

current diversion (or energy diversion): Theft of electric power in which current is diverted to bypass the meter. More generally, any type of tampering to obtain unmetered service.

curtailment: A temporary, mandatory load reduction under emergency conditions taken after all possible conservation and load management measures, and prompted by problems of meeting baseload rather than an upswing or peak.

customers: Industrial, agricultural, large retail, commercial and residential.

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declining block rate: A rate structure that prices successive blocks of electricity use or kilowatt demand at a decreasing per-unit price. The more electricity a customer uses, the less the per-unit price.

dedicated resources: Utility-owned generating resources used or dedicated to serving firm load. A utility declares these resources in its power sales contract with BPA.

demand: The rate at which electric energy is delivered to or by a system at a given instant or averaged over a designated period, usually expressed in kilowatts or megawatts.

demand forecast: An estimate of the level of energy that is likely to be needed at some time in the future.

demand-side management (DSM): Strategies for reducing consumption by influencing when and how customers use electricity. Demand-side management includes such things as conservation programs and incentives for switching electricity use from mid-day to evening.

deregulation: The loosening of federal and state laws and regulations that govern the generation, transmission and distribution of electricity.

direct access: Ability of a power producer to sell directly to the retail customer.

direct current (DC): An electric current that flows in one direction with a magnitude that does not vary or that varies only slightly.

Direct Service Industrial customers (DSIs): Industries that buy power directly from BPA rather than through retail utilities. The number of these customers is limited by law to those industries that were direct service customers on the date the Northwest Power Act was passed.

dispatch: The monitoring and regulation of an electrical system to provide coordinated operation; the sequence in which generating resources are called upon to generate power to serve fluctuating loads.

displacement: The substitution of less expensive energy generation for more expensive generation. Usually this means reducing or shutting down production at a thermal plant and using hydro power when it is available.

distribution: The transport of electricity to ultimate use points such as homes and businesses.

distribution utility (Disco): The regulated electric utility entity in a competitive world that would construct and maintain the distribution wires connecting the transmission grid to the final customer. This entity would make distribution service available to any qualified energy service company on comparable bases.

divestiture: The stripping off of one utility function from the others by selling or in some way changing the ownership of the assets related to that function. Most commonly associated with spinning off generation assets so that they are no longer owned by the shareholders that own the transmission and distribution assets. Divestiture, or legal separation, is distinguished from functional separation.

draft: Release of water from a reservoir, usually measured in feet of reservoir elevation.

drawdown: The distance the water surface of a reservoir is lowered from a given elevation as the result of releasing water. Drawdown can be expressed in terms of the acre-feet of stored water released.

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elasticity of demand: The degree to which consumer demand for a product responds to changes in price, availability or other factors.

electric and magnetic fields (EMF): Invisible force fields that surround the movement of electricity. Everything electrical produces EMF.

embedded cost: The fixed cost of all facilities in the power supply system, including generating plants, substations and distribution lines.

energy: Average power production over a stated interval of time, expressed in kilowatt-hours, megawatt-hours, average kilowatts or average megawatts.

energy content curve: A seasonal guide to the use of storage water from reservoirs operated by parties to the Pacific Northwest Coordination Agreement. The curve charts reservoir levels and is designed primarily to assure that the first increment of water above that required for meeting firm load is used to refill the reservoir with 95 percent confidence by the end of July. The curve defines rights, entitlements, operations and limitations that the reservoir owner and downstream projects have for the use of storage water under the Coordination Agreement.

environmental externalities: An 'externality' exists when one party's activities affect the life or activities of the other parties in ways that are not factored into the production and pricing decisions of the first party. Such impacts may be positive or negative. With respect to utility activities, if costs are imposed on society that are not counted in electricity resource selection and operation decisions, two effects can be expected: (1) certain resources may be selected to meet incremental capacity requirements over alternatives that have higher 'direct' costs, but whose external costs are so low that these alternatives, if selected, would impose lower total costs on society; and (2) the product (electricity) will be underpriced, so that, from an economic perspective, too much will be consumed. In sum, these two effects will result in inefficient utilization of society's resources - as well as the imposition of costs, without compensation, on parties who have little or no say in the polluting firm's decisions.

exempt wholesale generator (EWG): A class of generators defined by the Energy Policy Act of 1992 that includes the owners and/or operators of facilities used to generate electricity exclusively for wholesale or that are leased to utilities.

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Federal Base System (FBS): The system defined by the Northwest Power Act to be: (1) the Federal Columbia River Power System (FCRPS) hydroelectric projects; (2) resources acquired by BPA under long-term contracts in force on the date of the Act; and (3) resources acquired by BPA to replace reductions in capability of FCRPS resources and contracted resources.

Federal Columbia River Power System (FCRPS): The FCRPS is made up of: (1) the hydroelectric generating projects constructed by the Corps of Engineers and the Bureau of Reclamation in the Northwest; (2) the power BPA has acquired through net billing and exchanges; and (3) the electric transmission system constructed and operated by BPA.

Federal Energy Regulatory Commission (FERC): A federal agency responsible for regulating key activities of the nation's natural gas utilities, electric utilities, natural gas pipeline transportation utilities and hydroelectric power producers.

firm energy load carrying capability (FELCC): The amount of firm energy that can be produced from a hydroelectric power system based on that system's lowest recorded sequence of streamflows and the maximum amount of reservoir storage currently available to the system.

firm power: Electric power that is guaranteed by the supplier to be available during specified times except when uncontrollable forces produce outages. Firm power consists of either firm energy, firm capacity or both.

fish cap: A memorandum of agreement (MOA) entered into by BPA, the Corps of Engineers, Bureau of Reclamation, US Fish and Wildlife Service and National Marine Fisheries Service concerning BPA's financial commitment for Columbia Basin fish and wildlife costs. The MOA states that BPA's fish and wildlife costs will be limited to an average of $435 million per year for the fiscal years 1996 to 2001.

fish ladder: A device made up of a series of pools similar to a staircase that enables fish to migrate upriver past dams.

fish passage facilities: Features of a dam that enable fish to move past the dam without harm. Generally these are an upstream fish ladder or a downstream bypass system.

fixed cost: Costs of generation projects incurred regardless of the amount of energy produced. Such costs normally include capital costs, the cost of financing construction (in the form of interest) and insurance.

flow: The volume of water passing a given point per unit of time. flow augmentation: Water from a storage reservoir added to enhance flow, particularly to aid fish migration.

forced outage: An unforeseen outage that results from emergency conditions.

forced outage reserves: An amount of peak generating capability planned to be available to serve peak loads during forced outages.

forecasting: The process of estimating or calculating electricity load or resource production at some point in the future.

fuel switching: Substituting one fuel for another based on price and availability. Large industries often have the capability of using either oil or natural gas to fuel their operation and of making the switch on short notice.

full requirements customers: Utilities that generate no power, relying instead on BPA for all of the power needed to meet their total load requirements.

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generation: The act or process of producing electricity from other forms of energy, such as steam, heat or falling water. The term also refers to the amount of electric energy produced.

generation company (Genco): A regulated or non-regulated entity (depending upon the industry structure) that, in a restructured environment, would operate and maintain generating plants. The Genco may own the generation plants or interact with the short-term market on behalf of plant owners. Genco is sometimes used to describe a specialized "marketer" for the generating plants formerly owned by a vertically integrated utility.

generation costs: Costs to produce electricity or acquire it by contract.

general transfer agreements (GTAs): Transmission arrangement by which BPA wheels federal power over the transmission grid of another (generally, investor-owned - though not exclusively) utility in order to provide power to public utilities which are not directly connected to the main BPA transmission grid.

geothermal: Power generated from heat energy derived from hot rock, hot water or steam below the earth's surface.

green marketing/green pricing: The offer for sale at either wholesale or retail, power products from renewable resources, i.e., "green power." Providing consumers who believe that the benefits of renewable resources are not fully reflected in market-driven resource development with the opportunity to purchase "green power."

grid: The linking system of transmission lines, regionally and locally.

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head: The vertical height of the water in a reservoir above the turbine. In general, the higher the head, the greater the capability to generate electricity.

historical streamflow record: The unregulated streamflow data base of the 50 years from July 1928 to June 1978. The data are modified to take into account adjustments due to irrigation depletions and evaporations for the particular operating year being studied.

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independent power producer: A non-utility power generating entity, defined by the 1978 Public Utility Regulatory Policies Act, that typically sells the power it generates to electric utilities at wholesale prices.

independent system operator (ISO) or independent grid operator (IGO): Independent manager of transmission lines to assure safe and fair transfer of electricity from generators to distribution companies.

industrial bypass: A situation in which large industrial customers buy power directly from a non-utility generator, bypassing the local utility system. Deregulation of generation and transmission has opened up the opportunity for large electricity users to purchase services from a supplier other than the local retail utility.

in-lieu energy: Under the Coordination Agreement, energy exchanged between a reservoir owner and the owner of a downstream project. The agreement allows reservoir owners to retain water above a reservoir's energy content curve; however, owners of downstream projects may request release of such water. Upstream project owners must then release the water or provide an amount of energy in-lieu of the release equal to the amount of energy which could have been generated downstream had the release been made.

insufficiency: The lack of sufficient federal capacity or energy resources to serve BPA's firm load capacity, its energy commitments or both.

integrated resource planning (IRP): Also known as Integrated Resource Management, a planning process for new energy resources that evaluates the full range of alternatives, in order to provide adequate and reliable service to its customers at the lowest system cost. The alternatives can include new generation capacity, power purchases, energy conservation and efficiency, cogeneration and renewable energy resources. In a restructured electric industry there may be no mechanism to continue this process.

integrated utility: A company that provides a complete electric system, generation, transmission and distribution services, for its customers.

interchange energy: Under the Coordination Agreement, interchange energy assures all parties an equal ability to serve their firm loads. If a party cannot meets its load in a given month, that party has the right to request interchange energy from another that has a surplus. The party with excess is obligated to meet the request. The price of interchange energy is set by parties to the agreement.

interruptible loads: Loads that by contract can be interrupted if the supplier needs the energy to meet its firm loads. A portion of BPA's service to the DSIs is interruptible.

inverted rates: A rate structure that prices successive blocks of power use at increasingly higher per-unit prices. The more electricity a customer uses, the greater the per-unit price.

investor-owned utility (IOU): A privately-owned utility organized under state law as a corporation for the purpose of providing electric power service and earning a profit for its stockholders.

irrigation discount: This is a rate discount utilities can offer to customers who use electricity for irrigation pumping. BPA has made such a discount available to its wholesale customers during the irrigation season since 1985; whether this discount will be a feature of new BPA contracts will be determined in the contract negotiations.

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juvenile: The early stage in the life cycle of anadromous fish when they migrate downstream to the ocean.

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kilowatt (kW): A unit of electrical power equal to one thousand watts.

kilowatt-hour (kWh): A basic unit of electrical energy which equals one kilowatt of power used for one hour.

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levelized life-cycle cost: The present value of the cost of a resource, including capital, financing and operating costs, converted into a stream of equal annual payments. Unlike installed costs, levelized costs permit comparisons of resources with different lifetimes and generating capabilities.

life-line rates: An artificially low charge for a specified basic block of residential electricity followed by a higher rate for use beyond that block. Such rates are to assure that low-income customers have enough electricity for basic uses.

load: The amount of electric power delivered or required at a given point on a system.

load factor: The ratio of average load to peak load during a specific period of time, expressed as a percent.

load management: The management of load patterns in order to better utilize the facilities of the system. Generally, load management attempts to shift load from peak use periods to low use periods.

load shape: The variation in the magnitude of the power load over a daily, weekly or annual period.

low-density discount: This BPA rate discount benefits utilities that provide service to sparsely populated rural areas where distribution costs are spread over fewer customers. The Northwest Power Act mandates that there be such a discount, but the level of the discount is set by BPA.

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mainstem: The main channel of a river -- as opposed to the streams and smaller rivers that feed into it.

marginal cost pricing: A system of pricing designed to reflect the cost of adding new power facilities to a system. Sometimes referred to as incremental cost pricing.

megawatt (MW): A unit of electrical power equal to one million watts or one thousand kilowatts.

megawatt-hour (Mwh): A unit of electrical energy which equals one megawatt of power used for one hour.

market forces: Competition for sales, new alliances, innovative pricing structures, customer demand, customer choices of various kinds of services.

market power: Large companies owning a high percentage of generation that can wield size in the market place and dominate prices.

melded rate: A rate which reflects the combined costs of different sources of power. Typically costs of existing hydro projects and costs of newer thermal plants are said to be melded when combined or averaged together in one rate.

mill: One-tenth of one cent. The common unit for pricing electricity.

model conservation standards: Construction standards for new electrically heated residential and commercial structures, and conversion standards for residential and commercial structures that switch to electric space heating.

municipal utility: A utility owned and operated by a city.

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nameplate capacity (or installed capacity): A measurement indicating the approximate generating capability of a project or unit, as designated by the manufacturer. In many cases, the unit is capable of generating substantially more than the nameplate capacity since most generators installed in newer hydroelectric plants have a continuous overload capacity of 115 percent of the nameplate capacity.

National Energy Policy Act of 1992: A law aimed at increasing efficiency in the electric utility industry by enhancing competition in generation. It opens up transmission access in an unprecedented fashion by giving the Federal Energy Regulatory Commission authority to order utilities to provide transmission to other utilities, federal power marketing agencies or anyone else generating electric energy for sale.

National Environmental Policy Act (NEPA) of 1969: A law requiring agencies to consider the environmental impacts of major federal actions and to prepare environmental impact statements (EISs) which discuss these impacts and weigh alternatives. The law also requires public participation in the EIS process.

natural monopoly: A situation where one firm can produce a given level of output at a lower cost than can any combination of multiple firms. Natural monopolies occur in industries that exhibit decreasing average long-run costs with increasing size (economies of scale). Historically, electrical generation has been assumed to be a natural monopoly. This assumption is being questioned in the electrical industry restructuring debate.

net billing: A financial arrangement that allowed BPA to underwrite the costs of certain electric generating projects. Under net billing, utilities that owned shares in thermal projects assigned all or part of the generating capability of those resources to BPA. BPA, in turn, credited and continues to credit the wholesale power bills of these utilities to cover the costs of their shares in the thermal resources. BPA sells the output of the thermal plants, averaging the higher costs of the thermal power with lower cost hydropower. Washington Public Power Supply System Nuclear Projects 1, 2, and 3, are net billed.

nitrogen supersaturation: A water condition in which the concentration of dissolved nitrogen exceeds the saturation level of the water. Excess nitrogen can harm the circulatory systems of fish.

nonfirm energy: Energy that is not guaranteed to be continuously available. Nonfirm energy is available in varying amounts depending upon season and weather conditions.

nuclear reactor: A device in which a fission chain reaction can be initiated, maintained and controlled. Nuclear reactors are used in the power industry to produce steam for electricity.

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obligation to serve: Obligation by a utility to provide planning services for all customers indefinitely, to assure adequate supply of electricity into the future.

off peak: A period of relatively low demand for electrical energy, such as the middle of the night.

operating year: The 12-month period from August 1 through July 31. outages: Periods, both planned and unexpected, during which a power-producing facility ceases to provide generation or the transmission of power stops.

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Pacific Northwest Coordination Agreement (PNCA): An agreement between federal and non-federal owners of hydro generation on the Columbia River system, which resulted from the Columbia River Treaty. The PNCA governs the release of stored water to obtain the maximum usable energy and directs operations of the major generating facilities as if they belonged to a single owner.

PCBs: Synthetic chemicals (polychlorinated biphenyls), manufactured from 1929 to 1977, found in electrical equipment, such as voltage regulators and switches, and used to cool electrical capacitors and transformers. The manufacture of PCBs was banned in 1979, but there is still a great deal of PCB-contaminated equipment requiring disposal by utilities.

peak/energy exchange: Exchange of peaking capacity for off-peak energy between two (or more) systems producing electrical energy.

peak load: The maximum electrical load demand in a stated period of time. On a daily basis, peak loads occur at midmorning and in the early evening.

peak load plant: A power plant which is normally operated to provide power during maximum load periods. Examples are combustion turbines and pumped storage hydro.

peaking capability: The maximum peak load that can be supplied by a generating unit, station or system in a stated time period.

performance based ratemaking: Regulated rates based on performance objectives, not on actual costs.

photovoltaic conversion: The process of converting the sun's light energy directly into electric energy.

plant factor: The ratio of the average generation and capacity of a plant during a specified period of time, expressed as a percentage. Sometimes called capacity factor.

postage stamp rate: A rate for electric power service that does not vary according to distance from the source of the power supply.

power: A term usually meant to imply both capacity and energy.

power brokers and marketers: Companies seeking to sell generation to large industrial customers or to an aggregation of smaller customers.

power exchange: Part of the new framework, a spot price market for electricity.

power factor: The fraction of power actually used by a customer's electrical equipment compared to the total apparent power supplied, usually expressed as a percentage. Power factor indicates how far a customer's electrical equipment causes the electric current delivered at the customer's site to be out of phase with the voltage. This enables a power supplier to calculate a power factor adjustment for customers with large loads.

power marketing administration: Congress established five federal power marketing administrations (PMAs) to sell hydroelectric power generated by federal dams and power plants. BPA is the oldest of the PMAs.

predation: The act of one creature preying upon another.

preference: A legal directive that gives publicly-owned utilities and cooperatives priority access to federal power.

preference customers: Publicly-owned utilities and non-profit cooperatives which by law have preference over investor-owned systems and industrial customers for the purchase of power from federal projects.

priority firm (PF) rate: The rate for BPA's sales of firm power to preference customers. provider of last resort: A legal obligation (traditionally required of utilities) to provide services to a customer where competitors have decided they do not want that customer's business.

public purposes costs: These are the costs of conservation programs, renewable energy and environmental expenses -- such as fish restoration -- which are believed by some to be the obligation of utilities.

Public Utility Holding Company Act: A law enacted in 1935 to control the corporate abuses and misconduct of private power's public utility holding companies, such as pyramid schemes, overvaluation of assets and excessive services fees. The National Energy Policy Act of 1992 amended several sections of the act, enabling electric utilities to compete in the independent power market without becoming holding companies.

Public Utility Regulatory Policies Act of 1978 (PURPA): Federal law the requires utilities to purchase electricity from qualified independent power producers at a price that reflects what the utilities would have to pay for the construction of new generating resources (see avoided cost). Portions of the act were designed to encourage the development of small-scale cogeneration and renewable resources.

PUD: Public Utility District (in Washington) or People's Utility District (in Oregon); a governmental corporation established by voters to supply electric or other utility service.

pumped storage plant: A hydroelectric power plant which generates electric energy to meet peak load by using water pumped into a storage reservoir during off-peak periods.

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qualifying facilities (QFs): A designation created by the Public Utility Regulatory Policies Act of 1978 for non-profit power producers that meet certain operating, efficiency and fuel use standards set by the Federal Energy Regulatory Commission. QFs are small plants, generally 50 MW or less, which usually rely on renewable energy sources or cogeneration.

quartile: The Direct Service Industrial (DSI) customers' load is divided into four quartiles.

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rate design: The development of electricity prices for various customer classes to meet revenue requirements dictated by operating needs and costs.

real dollars: Dollars that do not include the effects of inflation. They represent constant purchasing power.

redds: Spawning nests made in the gravel beds of rivers by salmon and steelhead.

refill: The annual process of filling a reservoir; also refers to the point at which the hydro system is considered "full" from the seasonal snowmelt runoff.

region: The geographic area defined by the Northwest Power Act. It includes the states of Idaho, Oregon and Washington; Montana west of the Continental Divide; portions of Nevada, Utah and Wyoming that lie within the Columbia drainage basin; and any rural electric cooperative customer not in the geographic area described above, but served by BPA on the effective date of the Northwest Power Act.

regional transmission group (RTG): A large number of utilities, independent power producers and state agencies join to provide more equitable and easier access to power lines in an area covering many states. The first such RTG was approved May 16, 1995 - Western Regional Transmission Association. FERC has said it would defer to decisions made by such groups.

regulation: Supervision over rates and major decisions by elected officials or appointees of elected officials.

regulated monopoly: Utility with service area protection. regulatory compact: Long term set of agreements between regulatory agency and the companies that it supervises (IOUs and Public Utility Commission; and publicly-owned utilities and locally elected officials).

reliability: The ability of the power system to provide customers uninterrupted electric service at their point of service.

renewable resource: A power source that is continuously or cyclically renewed by nature. In the Northwest Power Act, a resource that uses solar, wind, hydro, geothermal, biomass or similar sources of energy.

requirements contract: A power sales contract between BPA and a customer requiring BPA to deliver an amount of wholesale power to meet the customer's firm electric power needs above any other generation the customer uses to meet those needs.

re-regulating reservoir: A reservoir located downstream from a hydroelectric peaking plant which stores the widely fluctuating discharges from the plant in order to release them downstream in a relatively uniform manner.

reserve capacity: Extra generating capacity available to meet unanticipated demands for power or to generate power in the event of loss of generation.

reserves: The electric power needed to provide service to customers in the event of generation or transmission system outages, adverse streamflows, delays in the completion of new resources or other factors which may restrict generating capability or increase loads. Reserves normally are provided from additional resources acquired for that purpose, or from contractual rights to interrupt, curtail or otherwise withdraw portions of the electric power supplied to customers.

resident fish: Fish that spend their entire life cycle in freshwater, such as trout and bass.

residential exchange: An accounting procedure, established in the Northwest Power Act, through which benefits of the Federal Columbia River Power System are passed on to all residential and small farm customers in the region.

restriction: A form of energy curtailment; BPA's exercise of a contractual rights to interrupt power deliveries to Direct Service Industrial customers.

restructuring: Reconfiguring the market structure by eliminating the monopoly on the essential functions of an electric company.

retail utilities: Utilities that sell power to end-users, such as residential customers, businesses and industries, as opposed to power wholesalers - such as BPA, which sell power to retail utilities for resale to end-users.

retail wheeling: The sale of electricity by a utility or other supplier to a customer in another utility's retail service territory. Wheeling refers to the use of the local utility's transmission and distribution lines to deliver the power.

retrofit: To weatherize an existing structure. Also, the process of modifying an electric generating plant after it is built to improve its performance.

revenue requirement: The amount of funds (revenue) a utility must take in to cover the sum of its estimated operation and maintenance expenses, debt service and taxes. During the rate-setting process, the calculation of the revenue requirement is compared to revenue produced by current rates to determine whether a rate increase is needed, and if so, to determine the overall size of the increase.

river miles: Miles from the mouth of a river; for upstream tributaries, from the confluence with the main river.

run: A general term referring to upriver migration of anadromous fish over a particular time and area - often composed of multiple individual breeding stocks.

run-of-river plant: A hydroelectric plant which depends chiefly on the flow of a stream as it occurs for generation, as opposed to a storage project, which has space available to store water from one season to another. Some run-of-river projects have a limited storage capacity (pondage) which permits them to regulate streamflow on a daily or weekly basis.

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scheduling: Operating a power system to balance generation and loads; managing the accounting, billing and information reporting for such operations.

scheduling utility: A utility that operates a generation control area within the Northwest, or any utility designated by BPA as a "computed requirements" customer.

seasonal exchange: A transaction that takes advantage of the seasonal diversity between Northwest and Southwest loads through transfers of firm power from north to south during the Southwest's summer load season and from south to north during the Northwest's winter load season.

sectors: The economy is commonly divided into four sectors for energy planning. These are residential, commercial (e.g., retail stores, offices and institutional buildings); industrial; and irrigation.

self-generation: A 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.

shaping: The scheduling and operation of generating resources to meet changing load levels. Load shaping on a hydro system usually involves the adjustment of water releases from reservoirs so that generation and load are continuously in balance.

share the shortage: An agreement among Northwest utilities, signed in late 1993, which sets forth a coordinated plan of action to respond to energy shortages.

smolt: A juvenile salmon or steelhead migrating to the ocean and undergoing physiological changes to adapt from a freshwater to a saltwater environment.

solar generation: The use of radiation from the sun for heating or the generation of electricity.

spill: Release of water from a reservoir over a spillway rather than putting it through turbines to generate electricity.

spillway: Overflow structure of a dam. spinning reserve: The unloaded (not in use) generating capacity of a system's firm resources that is available on five minutes' notice to take up load on a sustained basis.

steam generation plant: A thermal electric generating plant which creates steam to drive a turbine. storage energy: The energy equivalent of water stored in a reservoir above normal bottom elevation.

storage reservoir: A reservoir which has space for retaining water from springtime snowmelts. Stored water is released as necessary for purposes such as power generation, fish passage and irrigation.

stranded investment or stranded asset: Generation facilities, owned by existing utility companies, that produce electricity at above-market marginal prices.

streamflow: The rate at which water passes a given point in a stream, usually expressed in cubic feet per second (cfs).

substation: An electric power station which serves as a control and transfer point on an electrical transmission system. Substations route and control electrical power flow, transform voltage levels, and serve as delivery points to individual customers.

surplus energy: Energy generated that is beyond the immediate needs of the producing system. This energy may be sold on an interruptible basis or as firm power.

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tariff: A document, approved by the responsible regulatory agency, listing the terms and conditions, including a schedule of prices, under which utility services will be provided.

thermal generation: The production of electricity from plants that convert heat energy into electrical energy. The heat in thermal plants can be produced from a number of sources such as coal, oil, gas or nuclear fuel.

tiered rates: A rate design which divides customer use into different tiers, or blocks, with different prices charged for each.

time-of-day pricing: A rate design imposing higher charges during periods of the day when higher energy costs are incurred.

transition charge: A mechanism to assure fairness and stability for existing utilities as we shift to a new market structure. The net effect of transition charges will fall on customers who change suppliers during the transition phase. The purpose is to avoid cost-shifting, and to enable existing utilities to retire debt and compete fairly.

transition phase: Specific time periods for regulated activities as the new market structure evolves.

transfers to the general fund: Contributions in-lieu of taxes and franchise fees from city-owned utilities to their cities' General Fund.

transmission: The act or process of transporting electric energy in bulk from one point to another in the power system, rather than to individual customers

transmission grid: An interconnected system of electric transmission lines and associated equipment for the transfer of electric energy in bulk between points of supply and points of demand.

turbine: The part of a generating unit which is spun by the force of water or steam to drive an electric generator. A turbine usually consists of a series of curved vanes or blades on a central spindle.

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unbundled rates: Separate line-item charges for generation, transmission, distribution and other services.

unbundled services: The selling and pricing of services separately, as opposed to offering services "bundled" into packages with a single price for the whole package.

universal service: Electric service sufficient for basic needs (an evolving bundle of basic services) available to virtually all members of the population regardless of income. See obligation to serve.

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variable cost: The total costs incurred to produce energy, excluding fixed costs which are incurred regardless of whether the resource is operating. Variable costs usually include fuel, maintenance and labor.

variable rate: A rate BPA uses for its aluminum producing customers; the rate fluctuates up and down with changes in the world price of aluminum.

vertical integration: An arrangement in which 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 in which a utility owns its own generating plants, transmission system, and distribution lines to provide all aspects of electric service. See unbundling.

volt: The unit of measurement of electromotive force. It is equivalent to the force required to produce a current of one ampere through a resistance of one ohm.

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water budget: A part of the Northwest Power Planning Council's Fish and Wildlife Program, calling for a specific amount of water to be released from reservoirs to augment streamflows during the downstream migration of juvenile salmon and steelhead.

watt: An electric unit of power or a rate of doing work (see kilowatt and megawatt).

wheeling: The use of the transmission facilities of one system to transmit power for another system.

wholesale power market: The 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 wheeling: Selling generated electricity to wholesale buyers for them to resell to retail customers.

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*Glossary of Electric Industry Terms compiled by PPC for Public Power Fundamentals, 1995; Restructuring Terms' glossary partially based on glossary assembled by the Rhode Island Governor's Policy Office and the National Council on Competition and the Electric Industry.