Sign In
Definitions - R
A     B     C     D     E     FGH     IJK     L     M     NO     PQ     R     S     TUV     WXYZ    
Any channel for enclosing and for loosely holding wires, cables or busbars.
A power transmission circuit fed from one end only. Also see network line.
A power system in which independent feeders branch out from a common source of electrical supply.
Energy traveling as a wave motion, such as low-temperature, infrared radiation emitted from the sun.
The process of emitting: energy waves, such as heat and light from the sun to the earth or heat from the earth to space; particles of matter from the disintegration of the nuclei of atoms, such as gamma rays.
1) The presence of unwanted radioactive matter. 2) Deposition of radioactive material in any place where it may harm persons or make products or equipment unsuitable or unsafe for some specific uses.
The spontaneous disintegration or change in energy state of an unstable nucleus of an atom accompanied by the emission of alpha, beta, or gamma rays.
Frequency in the portion of the electromagnetic spectrum between audible frequencies and infrared frequencies. Present practical limits are roughly 10 kilohertz to 100,000 megahertz.
The radio noise field emanating from transmission system equipment or circuits.
The radio noise voltage appearing on transmission system conductors or equipment.
Impairment of the reception of a wanted radio signal by an unwanted radio signal or disturbance, usually expressed in microvolts. Usually the result of partial electrical discharges (corona).
An enclosure for protecting an antenna from the harmful effects of its physical environment but not affecting its electrical performance.
An odorless, colorless, tasteless inert gas formed by the natural breakdown, or radioactive decay, of the radium that occurs in trace amounts in soils and rocks.
The short-lived decay products of radon that can attach to water vapor, dust, and smoke particles.
The area of noticeably less rainfall on the lee side of a mountain or mountain range than on the windward side. Caused by condensation and precipitation from moist air occurring as air flows up and over the windward side of a mountain or mountain range so the air descending the leeward side is much drier.
The angle or distance that a pole is tilted; may be in line or traverse to the line.
1) The amount of conservation that a program can acquire annually. 2) The rate at which the power output of a generator or generating project can be increased or decreased.
See remedial action scheme.
See Regional Assessment of Supplementation Projects.
The value, specified by a regulatory authority, upon which a utility is permitted to earn a specified rate of return.
The process under 7(i) of the Pacific Northwest Electric Power Planning and Conservation Act in which BPA informs customers of its intention to adjust the power rates it intends to charge its customers for a following period (usually two years) and holds public hearings before submitting the proposed rates to the Federal Energy Regulatory Commission for approval.
Rate cap. An upper limit, represented either by a number or a formula, above which a particular rate may not rise.
The development of electricity prices for various customer classes in order to meet revenue requirements dictated by operating needs and costs (such as revenue requirements, rate stability, fairness, efficiency, ease of administration).
The formal process of submitting BPA’s proposed rate changes to the Federal Energy Regulatory Commission for approval.
1) A utility, large industry, or Federal agency that buys power from BPA. 2) More generally, anyone who pays for the end use of electricity.
A combining of loads, as specified by various provisions of section 7 of the Pacific Northwest Electric Power Planning and Conservation Act, to which a single rate shall apply.
The rates that BPA charges for the power it sells at wholesale from Federal hydroelectric projects in the Northwest and for delivering power over its transmission lines. Rates are established through a public process (the Wholesale Power and Transmission Rate Proceedings) and approved by the Federal Energy Regulatory Commission. By law, BPA rates are designed to pay all costs of producing and transmitting power, interest on capital investment, and amortization. Power revenues must also pay a portion of the irrigation cost of Federal projects judged to be beyond the ability of irrigators to pay. As a group, also called wholesale rates.
The power rate governed by section 7(c) of the Pacific Northwest Electric Power Planning and Conservation Act that applies to large electricity-intensive industries such as aluminum smelters and metals-reduction plants to which BPA sells power directly. Also called 7(c) rate.
The transmission rate BPA charges for use of the Federal transmission grid to wheel power for others on a nonfirm basis.
The rate BPA charges for capacity that is made continuously available on a demand basis during the year or during the five months June through October, and in return for which the purchaser replaces the energy associated with the delivery of the capacity.
The rate BPA charges to wheel blocks of firm power across the main grid or network from one point to another point using a distance formula.
The power rate BPA usually charges its direct-service industrial customers, including for advance energy; demand charges are differentiated on both a daily and seasonal basis, and the energy charge is differentiated based on an analysis of the cost of seasonal hydro storage.
The rate BPA charges to integrate a utility’s resources across the BPA main grid on a postage-stamp basis.
The wholesale transmission rate charged for power transmitted across the lines connecting the Pacific Northwest with British Columbia.
The transmission rate BPA charges for use of the southern intertie (two 1,500-kV AC lines and one 800-kV DC line) connecting the Pacific Northwest with the Pacific Southwest at the California-Oregon border (alternating current) and the Nevada-Oregon border (direct current).
The rate BPA charges for firm power purchased for resale or direct consumption by customers in the Pacific Northwest, other than direct-service industrial customers, to serve new large single loads of public bodies and cooperatives, and the load growth of investor-owned utilities plus any of their firm power deficit in the year prior to December 5, 1980. Also see new large single load.
The rate BPA charges for energy that it supplies without guarantee of continuous availability (the amount and time of availability determined solely by BPA), and that it supplies inside and outside the Pacific Northwest.
A rate charged by BPA to purchasers of priority firm power who are a part of the residential and small farm class under section 5(c) of the Pacific Northwest Electric Power Planning and Conservation Act.
The rate BPA charges for firm power to be used within the Pacific Northwest by public bodies, cooperatives, Federal agencies, and IOUs participating in the residential and small farm exchange (residential exchange).
The rate BPA charges for firm power to meet unanticipated load growth for those purchasers with fixed supply contracts. Power for which BPA determines no other rate schedule is applicable and power to serve a purchaser’s firm power loads when BPA does not have a power sales contract in force with the purchaser.
The rate at which entities within or outside the Pacific Northwest may purchase BPA’s surplus firm power and surplus firm capacity. Available for sales of up to five years in length, and mutually agreed upon by BPA and the purchaser prior to delivery of the power.
The power rate BPA offered to its direct-service aluminum smelter customers in August 1986 for ten-year contracts, adjustable monthly based on the average market price of aluminum; often referred to as the variable rate.
Listings showing how electric bills of different types of customers are calculated for purchase of power and for use of the Federal transmission system.
The load that a machine, station, or system can carry under standardized conditions. For equipment, rating generally means nameplate rating. Also see capability, nameplate rating.
See Resource Conservation and Recovery Act.
See Rural Electrification Administration.
The component of impedance that does not dissipate energy. Inductive reactance stores magnetic energy and hinders the flow of alternating current. Capacitive reactance stores electric energy. Also see resistance.
See turbine.
The out-of-phase component of the total voltamperes in an electric circuit, usually expressed in var (voltamperes reactive). It represents the power involved in the electric fields developed when transmitting alternating-current power (the alternating exchange of stored inductive and capacitive energies in a circuit). See power factor.
1) In generation usage, refers to a nuclear reactor (See nuclear reactor). 2) In an electrical system, a device used to introduce inductive reactance into a circuit.
A reactor connected in series with a circuit or piece of equipment, used to limit the current that can flow under short-circuit (fault) conditions or other switching conditions.
An electromagnetic device connected between phases or between phase and ground, used to introduce inductive reactance in a system. Can be connected to a bus or to a line and used to absorb reactive (capacitance) power and lower system voltage.
The process in which the oxygen content of water that has been depleted by heat from thermal power plants or by a deep position in a reservoir is restored to normal levels.
See discount rate.
Dollars adjusted to eliminate the effect of inflation in order to represent constant purchasing power. Sometimes referred to as constant dollars. Also see nominal dollars.
The price rise of goods or services after adjusting for (removing the effect of) inflation.
See levelized costs.
1) The in-phase component of volt-amperes in an electric circuit; same as power. Also called active power. See reactive power. 2) At the immediate moment. Some scheduling of power happens on real time.
Pertaining to the performance of a computation during the actual time the process occurs so the results of the computation can be used in guiding the physical process.
BPA’s principal computer control mechanism used to dispatch and schedule over its system. Integrates data from the supervisory control and data acquisition computer system with logs and indices to track the condition of the system.
See U.S. Bureau of Reclamation.
The restoration of land to resemble its original condition or an acceptable substitute as to shape, vegetation, and wildlife, after the land has been disturbed, as in strip-mining.
The automatic closing of a power circuit breaker following an opening operation via relay action.
See relay.
The document notifying the public of a decision taken by a Federal agency on a proposed action, together with the reasons for the choices entering into that decision.
A device that converts alternating current into direct current.
Gravel nest created by female salmon or trout where its eggs are laid, subsequently hatched, and fry emerge.
Duplicated elements in a system or installation for the purpose of enhancing the reliability or continuity of operating the system.
1) The process of filling a reservoir. Also see system refill. 2) The point at which the hydro system is considered “full” (reservoirs have refilled) from the seasonal snowmelt runoff.
See bond refinancing.
1) An antenna element used to increase the directivity of the antenna. 2) A microwave reflecting surface (usually flat) placed in a radio beam to change the direction of the beam.
The change of direction experienced by a wave of any form of radiated energy (for example, radio waves or light waves) when passing from one medium to another.
See BPA service area.
A planning methodology to improve fish production in streams and rivers.
A contingency plan negotiated among Northwest utilities, BPA and state authorities to implement a controlled cur-tailment when a long-term energy shortage cannot be resolved through imports or inter-utility actions.
The amount of firm resources owned by all Northwest generating utilities and BPA that is in excess of forecasted firm loads.
A device for holding such quantities as voltage, current, or speed at a constant predetermined value. See voltage regulator.
A measure of the quantity of gaseous water vapor and an indicator of the atmosphere’s ability to lose heat to space at night. Usually expressed as a percentage of saturation, where 0 percent equals totally dry air and 100 percent equals fully saturated air.
1) An electro-mechanical device that closes contacts in response to current through a coil. 2) An electrical device that is designed to respond to specific input conditions by closing contacts or making a similar abrupt change in a control circuit. Inputs are usually electric but may be mechanical or thermal.
A device that visually indicates that a relay or some other device has operated, used primarily to indicate some abnormality on the power system.
A relay whose function is to assist another relay or control device by supplying supplementary actions. Some specific functions are: providing circuit seal-in functions; increasing available number of independent contacts; and providing contacts for interlocking.
Backup protection (as applied to a relay system) that operates independently of specific components in the primary protective system and is intended to operate if the primary protection fails or is temporarily out of service.
Responds to the difference between incoming and outgoing electrical quantities associated with the protected apparatus.
Responds to the relative phase position (direction) of a current with respect to another current or reference voltage.
Responds to input quantities (current and voltage) as a function of the electrical circuit distance between the relay location and the point of fault in a transmission line.
Responds to the frequency of an alternating electrical input quantity; may respond to an increase or a decrease in frequency.
Responds to system ground faults. May be overcurrent, distance, or a combination, with or without directional discrimination.
Operates when the current through the relay during its operating period is equal to or greater than its setting. Usually a combination of instantaneous and time delay units with or without directional discrimination.
A relay whose function is to detect defective equipment or other power system faults and to initiate appropriate control, such as tripping circuit breakers to isolate the trouble from the rest of the system. Common types on a power system include differential, directional, distance, frequency, ground, overcurrent, and voltage relay.
reclosing relay
A programming relay whose function is to initiate the sequence of actions leading to automatic reclosing of a circuit breaker.
A relay scheme for remote tripping of a circuit breaker in which a communications channel is used to transmit a trip signal from a relay location to a remote location. Transfer trip may be direct and without supervision at the remote end or permissive (that is, coordinated with a near-end trip) and with supervision at the remote end, or combinations of both.
Responds to voltage. May be an overvoltage relay, an undervoltage relay, or a combination of both.
An assembly, usually consisting of measuring units, relay logic, communications interfaces, and necessary power supplies. A permissive relay system is one in which the functional cooperation of two or more relays is required before a control action can become effective.
1) The measure of the ability of a power system to provide uninterrupted service, even while that system is under stress. 2) In a relay or relay system, a measure of the degree of certainty of correct performance. Denotes certainty of correct operation together with assurance against incorrect operation from all extraneous causes.
Written standards for the BPA transmission system that define the acceptable effects that problems should be allowed to cause on the system, on power load, and on generation. Defines objectives that the transmission system should meet.
A measurement unit for the dose of ionizing radiation which includes a consideration of the biological effect of that particular radiation on human beings.
1) The actual construction or implementation phase of a Superfund site cleanup that follows development of engineering drawings and specifications for a site cleanup. 2) In a power system, measures that are taken, such as generator dropping or application of a dynamic braking resistor, to protect the system against cascading outages or other major system disturbances.
A set of fast, automatic control actions used to ensure acceptable power system performance following disturbances. Equivalent to stability control schemes. Also called special protection system, special stability control, and emergency control.
An in-depth study designed to gather the data necessary to determine the nature and extent of contamination at a Superfund site, to establish criteria for cleaning up the site, to identify preliminary alternatives for cleanup actions, and to support the technical and cost analyses of alternatives.
A long-term action that stops or substantially reduces a release or threat of a release of hazardous substances that is serious but not an immediate threat to public health.
The control of an operation or device from a distance. Remote control may be by direct connection or over a microwave channel. See supervisory control and data acquisition.
A system that meters power deliveries and provides the data to a central computer when queried by telephone. Also called revenue metering system.
Any energy that has recently originated in the sun and is continually replenished, including direct and indirect solar radiation and intermediate solar energy forms such as wind, ocean currents and waves, hydropower, photovoltaic energy, products of photosynthetic processes, geothermal, and organic wastes.
1) A resource whose energy source is not permanently used up in generating electricity. 2) In the Pacific Northwest Electric Power Planning and Conservation Act definition, a resource that uses solar, wind, hydro, geothermal, biomass, or similar sources of energy and that is used either for generating electric power or for reducing the electric power requirements of a customer.
BPA’s responsibility to collect sufficient revenues from rates to return the reimbursable power costs of each Federal Columbia River Power System investment and each irrigation assistance obligation within the time prescribed by law or, in the absence of a specific legislated period, within 50 years from the date the investment is capable of producing revenue or within the investment’s average service life, whichever is less. Also see revenue requirement study.
The study in which BPA calculates the annual interest and amortization payments on the Federal investment for the repayment period such that each investment is repaid by its due date. The study is performed annually, and is used in determining revenue requirements.
A station in between terminals of a microwave system that receives a signal from a distant station, and amplifies and transmits the signal to another distant station. Most repeaters do this in both directions simultaneously.
Energy that industries or utilities acquire through an agent to serve interruptible loads which BPA is unable to supply. Replacement energy purchases provide industries with energy to replace the amounts of industrial firm power which BPA restricts under contract provisions. Replacement for restrictions of authorized increases of industrial firm power may also be acquired in this fashion.
The quantity of a hazardous substance that must be reported under the Comprehensive Environmental Response, Compensation, and Liability Act.
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.
See reservoir.
A fee charged by a generation facility owner or manager to a purchaser or potential purchaser for holding the facility in readiness to generate specifically to that purchaser. Also known as standby fee.
See capacity.
For a power plant or transmission facility, extra capacity above the amount projected to be needed, to allow for unanticipated demand for power, equipment failure, or other unforeseen events.
reserve power (RP) rate
See rates.
1) In BPA financial management, a portion of the amount of retained earnings held and set aside for a specific purpose. 2) In a power system, the capability in excess of that required to carry the normal system load. Electric power needed to serve customers in the event of generation or transmission system outages, adverse streamflows, delays in completion of new resources, or other factors which may restrict generating capability or increase loads. Normally 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.
An amount of peak generating capability planned to be available to serve peak loads during forced outages.
Reserve capacity (generating) capable of being used within a specified time. Interruptible loads that can be disconnected within a specified time may also be considered as non-spinning reserve.
Extra generating capacity available to meet unanticipated demands for power.
Generating capacity connected to the system (in service) and ready for immediate response to load variations.
The space behind and body of water held back by a dam. Also see dam.
A reservoir that normally refills at the end of each July. Water is released, as necessary, to meet power production, navigation, irrigation, and fish obligations.
A reservoir that cannot refill all usable storage by the end of each annual high-water season.
re-regulating reservoir
A reservoir located downstream from a hydroelectric plant normally operated to provide power during maximum load periods. Has sufficient pondage to store the widely fluctuating discharges from the peak-load plant and to release the discharges in a relatively uniform manner downstream.
The rate at which water, released from storage behind a dam, reduces the pool elevation of the reservoir.
The level of the water stored behind a dam. Also can be the reservoir’s elevation above sea level. See head.
The volume of water in a reservoir at a given time.
Fish species that reside in freshwater during their entire life cycle.
A contract with a utility under the Residential Exchange Program.
The amount of power equal to the demand of a utility’s residential and small-farm customers adjusted according to section 5(c) of the Pacific Northwest Electric Power Planning and Conservation Act.
The period of time during which a utility’s retail rate schedules are in effect, commencing with the effective date of the schedules and ending with the effective date of new retail rate schedules. No such period can commence prior to or extend beyond the term of the utility’s residential exchange agreement.
The arrangement, based on section 5(c) of the Pacific Northwest Electric Power Planning and Conservation Act, whereby regional utilities sell BPA an amount of power equal to their residential and small-farm load at their average system cost in exchange for Federal electric power, and pass on the cost benefits to their residential and small-farm customers in the form of lower retail rates.
See sector.
The component of impedance that resists the flow of charge through it causing a dissipation of energy as heat. The heat dissipated is equal to the current (amperes) squared multiplied by the resistance (P = I2R). Since resistance opposes the flow of current, the larger the resistance the lower the current for a given source (driving) voltage. Also see reactance.
A device that introduces resistance into a circuit; as commonly supplied, resistors consist of wire, metal ribbon, cast metal, or carbon compounds. See ohm.
A device used to help maintain stability in a power system by absorbing electrical energy for a brief period following a system disturbance. The BPA resistance brake, installed at Chief Joseph Substation and switched on for about one-half second when certain abnormal system conditions are detected, consists of five kilometers (three miles) of one-half inch stainless steel wire for each of the three phases of the power system, each wire strung in a vertical configuration on a modified transmission tower.
Electrically, resonance occurs when the capacitive reactance and inductive reactance of a device are adjusted so that the device either maximizes or minimizes current flow at a specific frequency.
If the circuit capacitance and inductance are in parallel, the device minimizes current flow at its resonant frequency; however, large currents circulate in the capacitor and inductor.
If the circuit capacitance and inductance are in series, the device exhibits a low impedance at resonance and the current flow through the device is maximized at resonance.
A source of electric power or capability, or a conservation measure.
A resource that can be counted on, for power planning purposes, to contribute a specific amount to meet future loads.
The process by which BPA purchases electric power from generating resources and/or the reduction in load through BPA conservation programs. Under the Pacific Northwest Electric Power Planning and Conservation Act, BPA gives priority in acquiring resources to conservation, renewable resources, and resources using waste heat (cogeneration) or having high fuel conversion efficiency. BPA is prohibited by law from owning its sources of power.
A 1976 amendment to the first Federal law relating to solid waste. Regulates management and disposal of solid and hazardous wastes.
A BPA plan that sets out siting and licensing actions that can be taken if planned conservation and generating resource activities prove inadequate to meet BPA firm loads.
The different types of resources that contribute to an electric system’s ability to meet loads to generate power within a given area or for a given utility.
See option.
The determination of future BPA resource requirements, which is based on the estimate or projection of the amount of new electricity generation and conservation needed to meet future loads.
1) All of the generating resources that are available to meet load. 2) The three resource pools set up in section 7 of the Pacific Northwest Electric Power Planning and Conservation Act for BPA ratemaking.
BPA’s biennial estimation of the resources that will be needed to meet future load growth, and the steps BPA will take to acquire those resources; published in even-numbered years.
A body of representatives of BPA’s utility customers, utility customer groups, industry groups, State agencies, and public interest groups that help compile and evaluate elements of the Resource Program.
The planned schedule of when and what resources will be available in the future to serve load in a given area or of a given utility.
A traditional economic tool used to depict or forecast the amount of a product available across a range of prices.
Particles small enough to be inhaled deeply into the lung and which are frequently toxic and can carry harmful pollutants.
An action authorized under the Comprehensive Environmental Response, Compensation, and Liability Act, either short-term or long-term, that may include but is not limited to: removing hazardous materials from a site to an Environmental Protection Agency-approved hazardous waste facility for treatment, containment, or destruction; containing the waste safely on-site; destroying or treating the waste on-site; and identifying and removing the source of groundwater contamination and halting further migration of contaminants.
The time required for an output to reach a specified value, following the initiation of a specified stimulus to a device or system.
From a customer’s standpoint, the time involved in restoring service after a transmission line outage or equipment failure that results in an outage to a customer. From an equipment standpoint, the time involved in relaying and switching to de-energize a transmission line after a fault occurs plus the time needed to re-energize the line after the fault clears.
An end-use consumer of relatively small quantities of any product or service, including electric service.
Power sold to ultimate, or end-use, consumers.
Utilities that sell power to end users, such as residential consumers, businesses, and industries; as opposed to power wholesalers, such as BPA, which sell power to retail utilities for resale to end users.
1) To install energy conservation measures in existing buildings. 2) To modify a piece of electrical equipment or generating plant after its construction to improve performance or efficiency.
The energy that is returned by a second utility to a first utility, equalling the amount of energy previously sent to the second by the first, under the terms of capacity sales and capacity energy contracts.
A condition such that if a certain rate is charged for a power sale, the resulting revenues will not be enough to recover the costs.
See financing.
See forecast.
See remote metering system.
1) The amount of revenue a utility must take in to cover the sum of its estimated operation and maintenance expenses, and debt service and coverage. 2) At BPA, the lowest amount of revenues necessary to recover the projected annual expenses of the Federal Columbia River Power System and the planned net revenues that ensure coverage of planned amortization payments and meet financial objectives.
A study filed with the Federal Energy Regulatory Commission that determines annual revenue requirements of the Federal Columbia River Power System and tests whether revenues from existing and proposed rates are sufficient to satisfy rate period revenue requirements, and to repay the Federal investment in the FCRPS within the allowable repayment period.
At BPA, aggregate gross earnings from all sources, whether or not collected, measured by the cumulative sales price of all goods and services actually delivered to customers.
In land acquisition usage, an agreement wherein a property owner grants another certain rights of use of the property. Most permits are temporary in nature and can be revoked by giving notice.
See request for proposal.
See radio interference.
See radio influence field.
An easement for a certain purpose over the land of another, such as the strip of land used for a road, electric transmission line, ditch, or pipeline. BPA usually acquires easements for its transmission lines, roads, and other facilities such as guys and anchors. Road rights-of-way are usually acquired in 6 or 15 meter (20 or 50 foot) widths; transmission line rights-of-way are usually acquired in the widths below. Also see corridor.
27-34 meters
90-110 ft.
27-38 meters
90-125 ft.
38-50 meters
125-165 ft.
See bus scheme.
Habitat or areas, usually adjacent to rivers, streams, or lakes, where the vegetation and microclimate are heavily influenced by water.
An alternating-current component on a direct-current voltage resulting from incomplete filtering. The percent of ripple is the ratio of its effective value to the average value of the total voltage, expressed in percent.
The qualitative and quantitative evaluation performed in an effort to define the level of danger to human health and/or the environment by the presence or potential presence and/or use of specific pollutants.
See radio influence voltage.
The land area drained by a river and its tributaries.
Miles from the mouth of a river or for upstream tributaries, miles from the point where the tributary joins the main river.
Classification of Pacific Northwest river resources and evaluation of stream resource categories, including anadromous fish, resident fish, wildlife, natural features, recreation, cultural features (such as Indian, historic, and archaeological resources), and institutional constraints.
See root-mean-square amplitude.
See Record of Decision.
See real time operations dispatch and scheduling system.
Volume of water contained above and in immediate contact with ceiling elements that acts as a heat sink storing either heat or cold.
The value of an alternating current or voltage that produces the same amount of heat in a certain resistance as an equal direct current or voltage is called the effective, or the RMS, value. The RMS value of a periodic quantity is the square root of the average of the squares of the values of the quantity taken throughout the period. If the periodic quantity is a sine wave, its effective RMS value is .707 of peak amplitude.
The rotating part of a generator or motor; for large synchronous generators or motors, the large rotor contains the field winding.
Reserve power rate. See rates.
See reportable quantity.
Water levels, represented graphically as curves, that guide the use of reservoir storage. Also see critical rule curves.
A distinct grouping of anadromous fish that migrates from fresh to salt water and back again to spawn at a particular time of year. Fall chinook and spring chinook, for example, are salmon runs named for the season they return as adults from the ocean.
The wheel containing the blades of a turbine. Water acts against the runner to produce torque.
That part of precipitation, snowmelt, or irrigation water that runs off the land into streams or other surface water.
Outlook for the amount of water expected to enter the Northwest power system, based primarily on winter measurements of snowpack.
See dam.
A Federal agency established by President Franklin D. Roosevelt in 1935 and authorized by the Rural Electrification Act of 1936. Makes loans and loan guarantees to provide electric and telephone service to rural areas.
A measure of a substance’s resistance to the transfer of heat. The higher the number, the greater the resistance. Used in determining relative heat loss from a building or conservation measure.