Glossary
Note: This glossary uses several acronyms and abbreviations defined in our listing.
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Abrogating - Terminating existing transmission or power supply contracts.
Access charge - A charge levied on a power supplier, or its customer, for access to a utility’s transmission or distribution system. It is a charge for the right to send electricity over another’s wires.
Acid rain - A term generally used to describe rain (and snow) with acidity lower than pH 5.6 (7 is neutral - the lower the number, the greater the amount of acid - normal rain is about 5.8). The acidity of precipitation in the United States due to acidic gases, other than carbon dioxide, is about 60 percent sulfuric acid, 30 percent nitric acid, and 10 percent other acids. The pollution is alleged to generally come from burning fossil fuels.
Action Committee for Rural Electrification (ACRE) - A voluntary political action group that supports candidates for national offices.
Active solar energy - Solar radiation is collected by using equipment which enables the user to transfer, distribute, or store the energy collected for use as required.
Adopt-an-Urban Congressman - A program through which representatives of local cooperatives call on urban members of the U.S. Congress to explain concerns of rural America; coordinated by the National Rural Electric Cooperative Association.
Affidavit - A written declaration of work done by an electrician.
Aggregator - An entity that combines the needs of several smaller customers into a larger block of power in order to get a better price.
Aggregate load - Similar businesses or groups that come together to form buying groups to negotiate a better rate for power.
Agribusiness - Includes all forms of business involved in agriculture, from producing, processing, storing and distributing commodities to manufacturing and distributing farm equipment or supplies.
Air conditioning hours - The number of hours in a 24-hour period in which the temperature exceeded 75 degrees Fahrenheit.
Air-to-air heat pump - (see air source heat pump)
Air source heat pump - A system that can supply both space heating and cooling. In the heating cycle, the heat pump removes heat from the outside air and pumps it indoors. When cooling, the heat pump absorbs heat from the indoors and rejects it to the outside. Also called air-to-air heat pump.
All-requirements customer - An electric utility that purchases all of its wholesale electric power from a single supplier.
All-requirements power contract - A contract primarily used by municipal electric and rural electric systems that describes a formal agreement entered into by a power supply system and its member distribution systems. In this contract the distribution systems agree to purchase all of their wholesale power needs from the power supply system at rates prescribed in the agreement and adjusted periodically to meet the power supply system’s cost of providing the power.
All-terrain vehicle (ATV)- Three or four-wheel vehicle designed for off-road use. May be used by electric utilities for line inspection and other tasks.
Allowance for funds used during construction (AFUDC) - Funds listed in the income account as a subdivision of “other income.” They represent amounts concurrently credited for interest charged to the cost of constructing new plants, based generally on the amount expended to date on particular projects.
Alternating current (AC) - A flow of electricity through a conductor that continuously reverses its direction of flow. Each change is called a cycle. The number of cycles during a given time period is called frequency. The standard frequency in the U.S. is 60 cycles per second (60 hertz) – current flows in a standard, alternating current circuit changes direction 60 times every second.
Alternative fuels - Sources of heat energy other than coal, nuclear power, natural gas or oil used to generate electricity; usually renewable materials such as wind, wood chips, solar power or garbage.
Ambient temperature - The temperature in the surrounding area.
American Institute for Cooperation (AIC) - Chartered as a university in 1925, it is the educational and research organization for cooperatives. Affiliated with the National Council of Farmer Cooperatives.
American Public Power Association (APPA) - A national service organization whose membership includes about 1,400 of the country’s 2,225 publicly-owned electric utility systems. Its members include municipalities, state power authorities, and power districts that generate, transmit, and/or distribute electric power.
Ammeter - An instrument that measures electric current in amps.
Ampacity - The current-carrying capacity, expressed in amperes, of an electric conductor under stated thermal conditions.
Ampere - A unit measuring the strength or force of electric current. It is proportional to the quantity of electrons flowing through a conductor, past a given point, in one second. This term is commonly used to indicate the size of circuit breakers and fuses. Amperes equal watts divided by volts: a 1,000-watt heater at 120 volts draws 8.33 amps.
Ampere’s Law - Magnetic field strength produced by an electric current.
Amperes Interrupting Current (AIC) - All over-current protection devices (fuses and circuit breakers) must have an interrupting rating.
Amplitude modulation - A radio broadcast system. AM is acceptable in all references.
Ancillary services - Those services necessary to support the transmission of electric power (replacement of losses, load regulation, etc.).
And/or issue - Charging the user incremental costs to improve the system or the average system cost (not both) when building additional transmission to serve a utility requiring access.
Annual electrical consumption - The amount of kilowatt-hours of electricity used by a consumer over a twelve-month period beginning January 1 and ending December 31 of the reporting year.
Annual meeting - Once-a-year gathering of members held according to a cooperative’s bylaws for the purpose of electing directors and conducting other cooperative business.
Annual system demand - The highest system demand occurring during a 12-month period.
Anthracite coal - A hard, high-rank coal with high-fixed carbon, which enables it to burn without much smoke emission.
Apparent power - Proportional to the mathematical product of voltage times current in any circuit. Designated kilovolt-amperes (kva) comprised of both real and reactive power. Power used to do work plus power stored during part of a cycle by inductance and capacitance and then returned to the power source.
Apprentice - A person who is in the process of learning a skill or trade, through a combination of employment, training, education, and practical experience under the direction of a qualified individual.
Arc - A discharge of electricity through a gas, a flow of current across an insulated medium.
Area coverage - The provision of electric service to everyone within a designated service area. Cooperatives agreed to provide area coverage in return for fixed interest financing from RUS.
Arrester - A device that limits surge voltages on equipment by discharging or diverting surge current, thereby preventing the build up of excessive voltage on the equipment.
Ash - The noncombustible residue of burned coal. Ash occurs in raw coal as clay, pyrite, or other mineral matter.
Atomic Industrial Forum Inc. (AIF) - Membership: industrial firms, labor, service and research organizations, education, and government agencies with interests in peaceful uses of nuclear energy (including generation of electricity).
Auxiliary equipment - Accessory equipment necessary for operating a generating station. This includes pumps, stokers, fans, pulverizers, etc.
Available but not needed capability - Net capability of main generating units that are operable but not considered necessary to carry load, and cannot be connected to load within 30 minutes.
Average cost - The revenue requirement of a utility divided by the utility’s sales.
Average demand - The amount of energy being consumed in an electric system over an interval in time, as determined by dividing the total number of kilowatt-hours by the number of units of time in the interval.
Average revenue per kilowatt-hour - The average revenue per kilowatt-hour of electricity sold by sector (residential, commercial, industrial, or other) and geographic area (State, Census division, and national) is calculated by dividing the total monthly revenue by the corresponding total monthly sales for each sector and geographic area.
Avoided costs - Costs a utility would otherwise have to pay to generate electricity if purchased from another source.
AWG - American Wire Gauge. The standard for measuring wire in America.
BBackup power - Power that is needed when regularly used generating units are not in service: during short-term emergencies or longer unplanned outages, and during periods of scheduled maintenance when the units must be shut down. Short-term backup power is generally called emergency power. Long-range backup power is often provided for in reserve sharing agreements.
Baghouses - Fabric filters used to eliminate fly-ash pollutants in the electric generating process.
Ballast - Device used to maintain current in circuit by varying resistance in response to changes in voltage.
Banks for Cooperatives (BCs) - Financial institutions that, as a part of the Farm Credit System, offer a complete line of credit and leasing services to agricultural cooperatives, rural utilities, and other eligible customers. The three BCs are: the Co-Bank National Bank for Cooperatives, headquartered in Denver, Colo.; the St. Paul Bank for Cooperatives, headquartered in St. Paul, Minn.; and the Springfield Bank for Cooperatives, headquartered in Springfield, N.Y.
Barrel (Bbl) - A volumetric unit of measure for crude oil and petroleum products equivalent to 42 U.S. gallons.
Base bill - A charge calculated through multiplication of the rate from the appropriate electric rate schedule by the level of consumption.
Baseload - The minimum amount of electric power delivered or required from a generating system over a specified period of time; usually measured in megawatts (1,000 kilowatts).
Baseload capacity - The generating equipment normally operated to serve loads on an around-the-clock basis.
Baseload plant - This is the kind of generating plant that provides the basic power that is needed year round. A baseload plant runs most of the hours of the year.
Base rate - The portion of the total electric rate that covers the cost of doing business unrelated to fuel expenses.
Basis - (trading terminology) The difference between the cash or product that is being hedged and the price of the futures contract being used as a risk management tool.
Bcf - The abbreviation for 1 billion cubic feet.
Bifurcating - Dividing customer contracts into two separate agreements, one for power sales and one for transmission service.
Billing demand - (see demand)
Biomass conversion - The production of fuel or energy from organic waste, whether it be plant material, animal manure, municipal sewage sludge, or a solid waste.
Bituminous coal - The coal ranked below anthracite. It generally has a high heat content and is soft enough to be readily ground for easy combustion. Bituminous accounts for the bulk of all coal mined in the United States.
Blackout - A temporary loss of electricity in an area because of the failure of generation or transmission equipment.
Block-rate - A charge for electricity under with the cost per kilowatt-hour changes as more kilowatt-hours are sold.
Block-rate schedule - A rate schedule showing different charges for various blocks of power or energy.
Boiler - A device for generating steam for power, processing, or heating purposes or for producing hot water for heating purposes or hot water supply. Heat from an external combustion source is transmitted to a fluid contained within the tubes in the boiler shell. This fluid is delivered to an end-use at a desired pressure, temperature, and quality.
Bond ratings - Values assigned to debt-securities, usually on the basis of earnings and fiscal soundness of the issuing companies. Two principal bond rating agencies are Moody’s Investor Service and Standard & Poor’s Corporation.
Bonding - The electrical interconnecting of conductive parts, designed to maintain a common electrical potential.
Bonds - A security certifying a loan of money at a specified rate of interest and for a specified period of time.
Bonneville Power Administration (BPA) - One of five regional federal agencies marketing electricity generated primarily from federal dams. Based in Portland, Ore., BPA sells power in six northwestern states. (See power marketing administrations)
Bottom ash - Slag or other residue remaining in the boiler after coal is burned. (See ash, fly ash, slag)
Branch lines - Distribution lines connect to a main feeder line to carry electricity to one or more customers.
Breeder reactor - The conventional, nuclear generating plant which produces heat by splitting atoms of uranium-235. A breeder reactor uses plutonium and produces a different form of plutonium in the process. A commercial breeder reactor, while providing heat to generate electricity, will make enough different plutonium to refuel itself and another breeder reactor every 10 to 15 years.
British thermal unit (Btu) - The amount of heat necessary to raise the temperature of one pound of water, one degree Fahrenheit.
Brownout - A condition resulting from lower than normal voltage, duration can be minutes or even hours. Caused by weather, animals, or motor vehicles interfering with distribution equipment.
Btu equivalent of fuels burned - The aggregate heat content of all energy; calculated so that any kind and quantity of fuel burned may be expressed as an equivalent quantity of some other kind of fuel burned.
Btu heat loss - The amount of heat that escapes in one hour's time through walls, ceilings, floors, windows, and doors.
Bulk marketing - Marketing electric energy and demand management, metering services, and billing services for large industrial customers.
Bulk power - Large amount of electricity. It is transported over high-voltage transmission lines.
Bus - An electrical conductor which serves as a common connection for two or more electrical circuits.
Bus bar - Large rigid, bar shaped or tubular conductors that are used to form a bus arrangement.
Bus-bar cost - The total cost of generating electricity, not including substation and transmission losses.
Bylaws - Rules for operating a cooperative approved by the membership.
Bypass isolation switch - A manually operated device used in conjunction with a transfer switch to provide a means of directly connected load conductors to a power source, and of disconnecting the transfer switch.
CCable - Strands of electrical conductor insulated from each other and laid together, often twisted around a central core. Cable may or may not have an insulated covering.
Cable jacket - A protective covering over the insulation, core, or sheath of a cable.
Call - (trading terminology) An options contract that gives the holder the right, but not the obligation, to buy futures at a specified price for a specified period of time.
Capacitor - A device that stores electrical charges and can be used to maintain voltage levels in power lines and improve electrical-system efficiency.
Capability - The maximum load that a generating unit, generating station, or other electrical apparatus can carry under specified conditions for a given period of time without exceeding approved limits of temperature and stress.
Capability, Net - The maximum load-carrying ability of the equipment, exclusive of station use, under specified conditions for a given time interval, independent of the characteristics of the load. (Capability is determined by design characteristics, physical conditions, adequacy of prime mover, temperature, headwater and tailwater elevations, and electrical use.)
Capability, Net Summer - The steady hourly output, which generating equipment is expected to supply to system load exclusive of auxiliary power, as demonstrated by tests at the time of summer peak demand.
Capability, Net Winter - The steady hourly output which generating equipment is expected to supply to system load exclusive of auxiliary power, as demonstrated by tests at the time of winter peak demand.
Capacitance - A physical property of all AC circuits that opposes a change in voltage; measured in farads.
Capacitance reactance - A measure of the opposition to current flow that is created by capacitance; measured in ohms.
Capacitor - Two electrodes, or sets of electrodes (often in the form of plates) separated from each other by an insulating material called the dielectric. Capacitors are used to store electrostatic charges.
Capacity - The amount of electric power delivered or required for which a generator, turbine, transformer, transmission circuit, apparatus, station, or system is rated by the manufacturer. Capacity is also used synonymously with capability.
Capacity charge - An element in a two-part pricing method used in capacity transactions (energy charge is the other element). The capacity charge, sometimes called demand charge, is assessed on the amount of capacity being purchased.
Capacity purchased - The amount of energy and capacity available for purchase from outside the system.
Capital credits - Money (income left over after expenses are paid) credited to member consumers of a cooperative, sometimes called patronage capital or equity capital.
Capital expenditures - Construction costs of new utility plants. These include costs of plant additions, improvements, and replacements, as well as expenditures for the purchase or acquisition of existing utility plant facilities.
Capital intensive - Having a high assets to sales ratio. Utilities often have $3 to $4 of assets for every $1 of sales while another manufacturer may have only 80 cents of assets for every $1 of sales.
Capital Term Certificate (CTC) - An unsecured, subordinated debt obligation of the CFC purchased by members as fifty-year investments. These investments are made as a condition of membership and for receiving a long-term loan. CTCs represent debt of CFC, which is subordinated to all other indebtedness, including that incurred in the capital markets through the sale of CFC bonds and commercial paper, and through bank loans.
Capitalization - The total of a companyıs long-term debt, preferred stock, and common stock equity.
Capitalization ratios - The ratios of long-term debt, preferred stock, and common stock equity to total capitalization.
Captive shipper - An industry, utility, farmer or other individual or entity who must rely on a single railroad line for shipping goods or receiving raw materials.
Ceiling cable - A resistance heating system that radiates heat by heating air in the room by convection.
Central station service - Electricity provided by a utility rather than generated by the user.
Chain reaction - A self-sustaining series of fissions which occur when a neutron splits an atom, releasing sufficient neutrons to cause many other atoms to split in the same way.
Charge - The basis of electric energy, manifested in current, voltage, and electric field as positive or negative elements that attracts unlike and repels like charged bodies.
Chlorofluorocarbons (CFCs) - Chemicals used as refrigerants and propellants in aerosol cans. Studies have shown that these compounds are destroying the ozone layer in the Earth's atmosphere.
Circuit - The path of electric current from the power source, through the conductors, through the device using the power, back through the conductors, and back to the source of power. The two types of circuits are:
Series circuit - A circuit in which electricity has only one path.
Parallel circuit - A circuit in which electricity has multiple paths.
Circuit breaker - A time-delay circuit interrupter, which opens the circuit when the current flow exceeds the breaker/rating for a short period of time.
Circuit recloser - A device that protects electric lines by momentarily interrupting service when a fault occurs, then restoring power automatically when the fault is cleared. This keeps outages from occurring when temporary problems happen, like branches touching a line.
Class rate schedule - An electrical rate given to similar classes of electric users such as residential or commercial.
Clean Air Act - A national law passed in 1963 and amended several times since, giving the U.S. Government broad powers to limit air pollution.
Clean-air technology - Involves a new generation of emission-control devices that can remove pollutants at coal-fired power plants more efficiently and reliably than scrubbers.
Clean-coal technology - A broad term covering any type of new technology for reducing emissions from coal-fired power plants. It is being developed as an alternative to scrubbers, which use as much as 5 percent of the total power the plant generates and produces solid waste that must be discarded.
Coal - A black or brownish-black solid combustible substance formed by the partial decomposition of vegetable matter without access to air.
Coal gasification - The conversion of coal to a gas that is suitable for use as a fuel.
Coal liquefaction -The process of converting coal to a liquid for use as synthetic petroleum.
Coal slurry - A process by which coal is ground fine enough to be suspended into a solution of water so it may be transported in an underground pipeline from a place close to where it is mined to the final destination for use.
Coefficient of performance (COP) - The ratio of the rate of heat delivered versus the rate of energy input in consistent units, or a complete, operating heat pump system under designated operating conditions.
Cogeneration - Consumers who have the capability of producing their own power and energy requirements, and selling their excess electricity back to the local electric company. Cogeneration is the dual use of steam (thermal and electrical) produced by an industrial process, such as a wood processing plant. The Department of Energy has encouraged the development of cogeneration resources.
Cogenerator - A generating facility that produces electricity and another form of useful thermal energy (such as heat or steam), used for industrial, commercial, heating, or cooling purposes. To receive status as a qualifying facility (QF) under the Public Utility Regulatory Policies Act (PURPA), the facility must produce electric energy and another form of useful thermal energy through the sequential use of energy, and meet certain ownership, operating, and efficiency criteria established by the Federal Energy Regulatory Commission (FERC).
Coincident demand - (see demand)
Coincidental peak load - The sum of two or more peakloads that occur in the same time interval.
Cold reserve - Thermal generating units available for service but not maintained at operating temperature.
Combination company - A company which provides more than one type of service, such as electric and gas service. If more than 95 percent of a company’s utility plant is devoted to one type of service, or if more than 95 percent of its operating revenues are derived from one type of service, it is not classified as a combination company.
Combined cycle - An electric generating technology in which electricity is produced from otherwise lost waste heat exiting from one or more gas (combustion) turbines. The exiting heat is routed to a conventional boiler or to a heat recovery steam generator for utilization by a steam turbine in the production of electricity. This process increases the efficiency of the electric generating unit.
Combined cycle unit - An electric generating unit that consists of one or more combustion turbines and one or more boilers with a portion of the required energy input to the boiler(s) provided by the exhaust gas of the combustion turbine(s).
Combined pumped-storage plant - A pumped-storage hydroelectric power plant that uses both pumped water and natural streamflow to produce electricity.
Commercial Consumer - A business establishment using electricity.
Commercial customer - A company in a non-manufacturing business. The utility may classify commercial service as all consumers whose demand or annual use exceeds some specified limit. The limit may be set by the utility based on the rate schedule of the utility.
Common mortgage (REA-CFC) - A mortgage held by REA and CFC used to secure loans made concurrently by the two agencies.
Common Use - Simultaneous use by two or more utilities of the same kind.
Comparability - The concept that transmission tariffs charged to third parties for transmission use must be the same as the transmission provider charges itself for comparable service, under similar terms and conditions.
Competitive transition charge (CTC) - A charge on an electric bill to recover a utility company's fixed cost for serving individual customers.
Conductor - A material that allows an electric current to pass through it. Also, the wire that carries electricity in an electric distribution or transmission system.
Congressional Budget Office - The arm of Congress that prepares fiscal estimates and budgets.
Connection charge - A one-time charge paid by a consumer for expenses involved in connecting the electrical service to the consumer’s home or business.
Conservation - Wise use of resources. (See efficiency)
Construction work in progress (CWIP) - A sub-account in the utility plant section of the company’s balance sheet representing the sum of the balances of work orders for utility plants in the process of construction, but not yet placed in service.
Consumption (fuel) - The amount of fuel used for gross generation, providing standby service, start-up and/or flame stabilization.
Contract demand - (see demand)
Contract price - Price of fuels marketed on a contract basis covering a period of one or more years. Contract prices reflect market conditions at the time the contract was negotiated and therefore remain constant throughout the life of the contract or are adjusted through escalation clauses. Generally, contract prices do not fluctuate widely.
Contract receipts - Purchases based on a negotiated agreement that generally covers a period of one or more years.
Cooperative electric utility - A system in which consumers of electricity own their own distribution system, which in turn owns the wholesale power supplier.
Cooperative Benefit Administrators, Inc. (CBA) - A wholly owned subsidiary of NRECA that processes and administers medical, dental and disability claims.
Cooperative Finance Corporation (CFC) - Common name for National Rural Utilities Cooperative Finance Corporation. (See National Rural Utilities Cooperative Finance Corporation)
Cooperative Month - An annual October commemoration of the importance of cooperative organizations.
COP - Coefficient of Performance. A measurement of a heat pump in the heating mode. The ratio of how much heat energy that is moved compared to how much energy is consumed in moving it.
Cost - The amount paid to acquire resources, such as plant and equipment, fuel, or labor services.
Cost-based rates - When consumers are on cost-based rates, each rate classification (residential, commercial, irrigation, etc.) pays its fair share of the electric companyıs costs; there is no subsidization between rate classifications. The total costs are divided into rate components based on the costs each class imposes on the cooperative.
Cost of service - The total amount required to provide a member consumer with electric service, not including the cost of energy used.
Cost-of-service study - Identifies what it costs the electric company to serve its various classes of consumers and provides the basis for evaluating different discount and incentive programs. The result of preparing this study is the development of “cost-based” rates.
Cove heater - A heating system installed on the wall near the ceiling, combining radiant and convective heat.
Critical mass - The point at which fuel in a nuclear reactor becomes capable of sustaining a chain reaction.
Current - The flow of electrons through a conductor.
Customer charge - Sometimes used to recover fixed costs for serving individual customers. These fixed costs are recovered through a flat charge to the customer, regardless of the amount of energy used. (See connection charge, facilities charge or service charge)
Customer choice - A term used interchangeably with retail wheeling in the electric utility industry. It allows retail customers to select the power supplier or generator they buy electricity from.
Customer classifications - Customers are categorized and charged by type of rate classification. These may include: residential, commercial, industrial, public street and highway lighting, public authorities, railroads and railways.
Customer transition charge - A charge on an electric bill to recover a utility company’s fixed cost for serving individual customers.
Cyberspace - A general reference to doing things electronically by computer over the Internet.
Cycle - In alternating current, the current goes from zero voltage to a maximum in one direction, back to zero and then to maximum in the other direction and back to zero again constituting a cycle.
DDC - Direct current.
Debt service coverage (DSC) - Ratio of margins, interest, and depreciation to debt service.
Debt-to-equity ratio - The amount a system owes in relation to the amount it owns.
Declining block rates - Residential rates in which the charge per kWh declines with increased use.
De-energized - Free from any electrical connection to a source of potential difference and from electric charge; not having a potential different from that of the earth.
Degree day - Used to estimate energy requirements for heating and cooling a building, this is a measure of the deviation of the mean daily temperature from a given standard, with each variance from the standard during a single day recorded as one degree day.
Delivery point - The point, usually a substation, to which electricity is transmitted from its generating sources.
Delta connection - A connection used in three-phased systems in which three coils (or three resistors) are connected end-to-end so that they effectively form a triangle.
Demand - The amount of electricity a customer takes at any given moment (varies from hour to hour, day to day, and season to season). This usage, which is expressed in kilowatts (not in kilowatt-hours), is called the “demand” on the system. Seasonal demands are affected by the number of hours of daylight, temperature extremes, and activities such as agricultural processes. These are five different types:
Billing demand - The demand, which is used to determine the demand charges in accordance with the provisions of a rate schedule or contract.
Coincident demand - Any demand that occurs simultaneously with any other demand; also, the sum of any set of coincident demands. Refers to the maximum demand which occurs at a specific time. For example, it may represent a distribution system’s demand at the time of its power supplier’s peak or an individual consumer’s demand at the time of his respective substation peak. The coincident demands are normally used in cost-of-service studies to allocate demand-related costs to consumer categories.
Contract demand - The demand (kW) for which a consumer agrees to pay whether the electrical power is used or not, which the seller must make available at all times.
Maximum demand - The greatest of all demands of the load that has occurred within a specified period of time.
Non-coincident demand - The highest demand over any given time frame, usually a month or a year, without regard to any other systemıs demand.
Demand charge - Electric rates paid by large retail customers and by wholesale customers (such as electric distribution cooperatives), which include separate charges for demand and energy. The demand charge is based on the customer’s maximum kilowatt demand on the system. The energy charge is based on the number of kilowatt-hours used.
Demand interval - A term used to describe any period of time during which the flow of electric energy is averaged in order to determine energy demand.
Demand meter - A meter that measures and records the kilowatt level (rate) at which electric energy is delivered to a system.
Demand option - A measure that an electric company or consumer may take to modify the demand levels or reshape the daily or seasonal load curve. Demand options encompass both economic and load control measures. For example, economic measures would include time-of-use rates, which offer a discount designed to attract loads to the off-peak period. An example of load control would be irrigation systems, which agree to have their power interrupted under agreed-upon conditions in exchange for a lower demand rate.
Demand ratchet - When applied, the current monthıs demand is compared with the previous 11 months’ demand and if a specified percentage of each of the 11 months or seasonal peak exceeds the present monthıs demand, the highest figure is used. Any figure can be used as the percentage, such as 60 percent, 75 percent or 100 percent. By using a demand ratchet, a strong price signal is given to encourage demand reduction at the critical times on the electric system. Coupled with the proper load management program, a demand ratchet can provide an effective means to limit capacity requirements as well as an incentive to use power in the off-peak months.
Demand rate - A rate combining a charge for the peak demand placed on the system, plus the charge for energy used during the billing period. A charge for electric service based on the size of a consumer’s installation or maximum kilowatt demand.
Density - The average number of consumers per mile of power line.
Department of Energy (DOE) - A federal department in Washington, D.C., created by President Carter by bringing together various energy-related agencies.
Depreciation - Defined in the REA Uniform Systems of Accounts as “the loss in service value of depreciable plant not restored by current maintenance resulting from causes against which no insurance is carried, such as wear and tear, decay, action of the elements, inadequacy, obsolescence, changes in the art, changes in demand, and requirements of public authorities.”
Deregulation - Reduction or elimination of government oversight of a segment of a private industry - usually a basic public service such as electricity, telecommunications or transportation services.
Design conditions - Cooling loads vary with inside and outside conditions. A set of conditions specific to a local climate is necessary to calculate the expected cooling load for a home.
Dielectric - A nonconductor of electricity. The property of an insulating material for opposing electrical fields.
Dip - (see sag)
Direct access - The ability of a retail customer to purchase commodity electricity directly from the wholesale market rather than through a local distribution utility.
Direct current (DC) - Electricity that flows through a circuit in a single direction. This current is maintained by a constant voltage.
Disaggregation - Separating a vertically integrated utility into smaller, individually owned transmission, distribution and generation units.
Disconnecting or isolating switch - A mechanical switching device used for changing the connections in a circuit, or for isolating a circuit or equipment from a source of power.
Dispatching - The operating control of an integrated electric system involving such operations as the assignment of load to specific generating stations to result in the most reliable and economical use of fuel supply. Also, the control of operations and maintenance of high voltage lines, substations and equipment, the operation of principal tie lines and switching, and the schedule of energy transactions with other connecting electric utilities.
Displacement power - Power from one generating source displaces power from another generating source. Usually this permits power from the latter source to be transmitted to more distant loads.
Dispersed generation - Small, decentralized generators such as diesel or combustion turbines, designed to supplement or replace power generated at large generating plants. Typically located at or near the point of use.
Distribution - That part of an electrical system that delivers power from a substation to the end user (customer). May include substations.
Distribution cooperative - An electric cooperative that purchases wholesale power and delivers it to member-owners.
Distribution lines - The conductors that deliver power from the substation to the service transformers. May be either overhead or underground.
Distribution system - That portion of a power system that functions to deliver power from a substation to the end user (customer). Typically consists of both overhead and underground components and may include substations.
Diversity - The effect of various types of electrical load on a utility system’s total demand for electricity. Loads, which create demand at different times, allow for more efficient use of available generating capacity.
Diversity interchange - Occurs when interconnected utilities experience peak loads at different times.
Diversification - Movement by a business into a new product or service outside its core business. In recent years many electric utilities have added a wide range of other services, which may be related to their energy-supply function - such as natural gas, propane, electric surge suppression and energy-efficient appliances - or complimentary services, such as home and business security, television programming and internet services.
Down - Denotes an electrical system component, or apparatus that is not operating.
Dragline - A large mobile excavator used in a strip mine to remove dirt and other material covering coal seams.
Drip-loop - An intentional sag placed in conductors that connect to overhead conductors; the drip loop will prevent rainwater from entering the weatherhead.
Drop-out - A momentary loss of voltage, possibly as short as part of a half cycle.
Dry-bulb temperature - The temperature measured by a standard thermometer.
DSC - Debt Service Coverage - Patronage capital and margins, plus depreciation and amortization expense, plus interest expense, divided by long-term debt service.
Dual-fuel heating - A system in which another heat source takes over when electricity is cut off at peak periods of electric use. Designed to keep costs down by making it unnecessary for a utility to call on more expensive sources of power during periods of high demand for electricity.
Dual fuel - A heating system that combines two fuel sources - electricity as a primary and propane, oil or other fuel as a secondary source (or vice versa). This is accomplished by either adding an electric heating unit to a gas furnace or adding propane or oil appliances as a backup system to an electric appliance.
Duct work - Passages usually made of sheet metal through which hot or cool air is blown in forced-air systems.
EEarth, earth - Capitalize when referring to Earth as a planet. Use lowercase when referring to soil, ground, etc.
Earth-coupled heat pump - An efficient electrical device for heating and cooling a home or other building by moving heat into or out of the structure. It uses an antifreeze solution or refrigerant in a pipe buried in the ground to collect or disperse heat (see geothermal system, ground-source heat pump, heat pump, water-source heat pump).
Easement - A right purchased from property owner(s) that allows utility companies to construct, operate, maintain and control facilities, such as transmission lines, on the property.
ECAR - East Central Reliability Coordination Agreement - One of ten regional electric power planning and pooling organizations that are members of the North American Electric Reliability Council.
Economic dispatch - Determines the share of the minute-by-minute load demand that each committed unit has, so that the overall system operating cost is minimized.
Economic Regulatory Administration (ERA) - ERA administers the department’s regulatory programs, other than those assigned to the Federal Energy Regulatory Commission. These functions include oil pricing, allocation, and import programs designed to ensure price stability and equitable supplies of crude oil, petroleum products, and natural gas liquids among a wide range of domestic users.
Economies of scale - A condition achieved when costs are reduced due to operation or output at a higher volume. For services, there may be economies of scale in delivering to a larger number of customers, allowing fixed costs to be spread over a larger number.
Ecowatts - An umbrella term for substituting electricity for conventional fossil fuels in a wide range of transportation and industrial uses, in order to obtain net energy savings and environmental gains.
Edison Electric Institute (EEI) - EEI members include investor-owned electric power companies and electric utility holding companies. Focuses on economics, industrial relations, and statistics of the electric industry. Acts as liaison with the federal government in all areas of electric utility operation and concern. Publications available. Library open to public by appointment.
Effectively grounded - Intentionally connected to earth through a ground connection or connections of sufficiently low impedance and having sufficient current-carrying capacity to prevent the buildup of voltages that may result in undue hazard to connected equipment or to persons.
Efficiency - Making maximum use of a resource. Requires less sacrifice than conservation, but stresses getting the most benefit out of each unit of a resource used.
Effective values - AC values for current and voltage based on the relationship that one ampere, peak value, of AC current produces the same heating effect as .707 amperes of DC current; also called RMS values.
EIA - The Energy Information Administration. An independent agency within the U.S. Department of Energy that develops surveys, collects energy data and analyzes and models energy issues.
Electric broker - An entity, which matches up producers of electricity with customers. Does not take ownership of or financial position in the transaction.
Electric Circus - A Federal Rural Electrification Administration traveling show that demonstrated uses of electricity to rural people from 1938 to 1942.
Electric continuity - An unbroken low-impedance path through which electrons flow.
Electric cooperative - A non-profit, member-owned electric utility company. Some cooperatives are G & T’s. As with other co-op businesses, any margin is returned to the consumers according to the amount of business conducted with the co-op.
Electric current - The flow of electrons in a conductor between two points having a difference in potential, generally expressed in amperes.
Electric energy - As commonly used in the electric utility industry, the use of power over time, commonly measured in kilowatt-hours.
Electric merchant - Term used with the advent of electric utility restructuring to denote an entity, which provides electricity and serves wholesale and retail customers.
Electric marketer - An entity, which purchases and resells electric energy and capacity to customers. Assumes ownership of the electric energy and/or capacity.
Electric plant (physical) - A facility containing prime movers, electric generators, and auxiliary equipment for converting mechanical, chemical, and/or fission energy into electric energy.
Electric Power Research Institute (EPRI) - A non-profit, research organization financed by electric utilities for the purposes of research and development of energy resources.
Electric rate schedule - A statement of the electric rate and the terms and conditions governing its application, including attendant contract terms and conditions that have been accepted by a regulatory body with appropriate oversight authority.
Electric thermal storage (ETS) - A type of heater that uses electricity during periods of low use to heat a ceramic material in an insulated cabinet to high temperatures, then releases the stored heat when electric use is high.
Electrocution - Death caused by electrical current through the heart, usually over 50 milliamperes.
Electric utility - A corporation, person, agency or other legal entity or instrumentality that owns and/or operates facilities within the United States, its territories or Puerto Rico for the generation, transmission, distribution or sale of electric energy primarily for use by the public and files forms listed in the Code of Federal Regulations, Title 18, Part 141. Facilities that qualify as co generators or small power producers under the Public Utility Regulatory Policies Act (PURPA) are not considered electric utilities.
Electricity - Electric current or power that results from the movement of electrons in a conductor from a negatively charged point to a positively charged point.
Electrification Council (EC) - Members include the electric industry trade associations and independent manufacturers. Conducts training programs and provides educational materials to industrial and commercial power consumers. Interests include the efficient production, use, and management of energy.
Electromagnetic field laboratory studies - research which involves exposing cells, tissues, and animals to electric or magnetic fields under a variety of controlled conditions.
Electromagnetic fields (EMFs) - Electric and magnetic fields often occur together, hence the term electromagnetic fields. They are found throughout nature and can be grouped by wavelength or frequency. The counterparts have the following definitions:
Electric fields - Created by voltage. Anytime something electric is plugged in it has an electric field, even if it is not in use. An electric field, in some instances, can be felt when the hair on your neck stands up during a lightning storm, for example. An electric field can be blocked by trees, walls, or buildings.
Magnetic fields - Created by current. Anything that carries electricity (such as power lines) and anything that uses electricity (such as home appliances in use) has a magnetic field. A magnetic field cannot be felt, and it passes through most objects.
Electron - Any of the negatively charged particles that form a part of all atoms.
Electronic meter reading - A system that uses a hand-held computer to record and store electric-use information from consumers’ meters then transmits that information to a central computer that prepares bills.
Electrostatic precipitator - An electronic pollution control device that removes particles of fly ash from a power plant's waste gases. The device first charges particles in the gas stream and then collects them on an oppositely charged surface.
Ellis Award - Award presented annually by the National Rural Electric Cooperative Association to an electric cooperative employee or director for outstanding service; named for Clyde T. Ellis, NRECA’s first general manager.
Embedded cost - Investments already made in a system to provide service, resulting in fixed costs such as debt and depreciation.
Embedded costs exceeding market prices (ECEMP) - Embedded costs of utility investments exceeding market prices are: costs incurred pursuant to a regulatory or contractual obligation; costs that are reflected in cost-based rates; and cost-based rates that exceed the price of alternatives in the market place. ECEMPs may become “stranded costs” where they exceed the amount that can be recovered through the asset’s sale.
Eminent domain - The power of a government body to condemn and use private property for public use with just compensation to the property owner.
Energy - The capacity for doing work; may be natural or manufactured. Electrical energy is usually measured in kilowatt-hours.
Energy audit - A study of residential, commercial or industrial buildings to show energy users how to save money by using energy more efficiently.
Energy Awareness Month - Sponsored each October by the U.S. Department of Energy and about 30 other organizations, including NRECA; designed to promote greater public awareness of the importance of (1) energy resources, (2) efficiency in energy use and (3) energy conservation.
Energy brokers - Companies that act as middlemen in an electronic marketplace in which electric power is priced, purchased and traded.
Energy charge - The part of an electric bill based on the amount of electricity used.
Energy deliveries - Energy generated by one electric utility system and delivered to another system through one or more transmission lines.
Energy efficiency - Refers to programs that are aimed at reducing the energy used by specific end use devices and systems, typically without affecting the services provided. These programs reduce overall electricity consumption (reported in megawatt-hours), often without explicit consideration for the timing of program-induced savings. Such savings are generally achieved by substituting technically more advanced equipment to produce the same level of end-use services (e.g. lighting, heating, motor drive) with less electricity. Examples include high-efficiency appliances, efficient lighting programs, high-efficiency heating, ventilating and air conditioning (HVAC) systems or control modifications, efficient building design, advanced electric motor drives, and heat recovery systems.
Energy efficiency ratio (EER) - The ratio of heating/cooling capacity (output) in Btus, divided by power input in watts. It is expressed as Btu/watt. The higher the EER, the more efficient the unit.
Energy Management System (EMS) - Through a master station comprised of the equipment and computer software, Tri-State's EMS provides instantaneous monitoring and control of complete system status such as electric load, voltage levels, and interruptions of service. It also provides information for sales or purchase transaction evaluations, efficient generation scheduling and generation-to-load matching.
Energy, off-peak - Energy supplied during periods of relatively low system demands, as specified by the supplier.
Energy, on-peak - Energy supplied during periods of relatively high system demands, as specified by the supplier.
Energy receipts - Energy generated by one electric utility system and received by another system through one or more transmission lines.
Energy Research and Development Administration (ERDA) - A federal agency created in 1974 to handle energy research and development activity.
Energy source - The primary source that provides the power that is converted to electricity through chemical, mechanical, or other means. Energy sources include coal, petroleum and petroleum products, gas, water, uranium, wind, sunlight, geothermal and other sources.
Environmental impact statement (EIS) - A statement based on a detailed study that sets forth the probable environmental consequences of building and operating large-scale facilities.
Environmental Protection Agency (EPA) - A federal agency that develops rules and regulations concerning environmental protection and monitors utilities and other industries.
EPAct - The Energy Policy Act of 1992.
Epidemiology - Research to try to establish whether there is a statistical association between selected groups of people with certain types of EMF exposure and particular diseases.
EPRI - Electric Power Research Institute, an organization financed by electric utilities for the purposes of research and development of energy resources.
Equity capital - (see capital credits)
ERA - U.S. Economic Regulatory Administration.
ERC Loan - Energy Resources Conservation Loan.
ERDA - U.S. Energy Research and Development Administration.
ESCO - Energy service company.
Ethanol - A grain alcohol, largely produced from fermented and distilled corn; used as an octane-enhancer in gasoline.
ETS - Electric thermal storage; a type of heating that utilizes off-peak electric energy to store heat energy in a medium such as special high-density brick.
Executive Order 7037 - Order issued by President Franklin D. Roosevelt on May 11, 1935, establishing the Rural Electrification Administration as part of the federal unemployment relief program.
Exit fee - A fee that may be charged when an electric utility customer switches power suppliers.
Externality - Hidden costs of an energy source or costs not covered in the price of fuel, such as the cost of clean coal technology and cleaning up acid rain.
Extra high voltage (EHV) - Voltage levels of transmission lines which are higher than the voltage levels commonly used. Generally considered to be any voltage greater than 345,000 volts.
FFacilities charge - Paid by the customer as reimbursement for facilities furnished. The charge may include operation and maintenance as well as fixed costs.
Facility - An existing or planned location or site at which prime movers, electric generators, and/or equipment for converting mechanical, chemical and/or nuclear energy into electric energy are situated, or will be situated. A facility may contain more than one generator of either the same or different prime mover type. For a cogenerator, the facility includes the industrial or commercial process.
Farm Credit Leasing Services Corporation - Provides leasing services to rural utilities in cooperation with the Banks for Cooperatives, which is a part of the Farm Credit System; headquartered in Minneapolis, Minn., with field offices in nine states.
FASB - The Financial Accounting Standards Board. Acceptable on second reference.
Federal Emergency Management Agency (FEMA) - Created to provide a single point of accountability for all federal emergency preparedness mitigation and response activities.
Federal Energy Administration (FEA) - Established by Congress in 1974 to ensure a sufficient energy supply for the U.S. and to make sure that priority needs are met during energy shortages.
Federal Energy Regulatory Commission (FERC) - In October 1977, FERC succeeded the Federal Power Commission (FPC) as the agency that sets and enforces the wholesale electric rates that investor-owned utilities charge rural electric cooperatives and other wholesale customers. The agency also licenses hydroelectric projects. It is a five-member board that is part of, but independent of, the DOE. Via the Energy Policy Act of 1992, it also has been charged with the responsibility to make the electric energy industry more market oriented as opposed to the long-standing monopoly orientation.
Federal Financing Bank (FFB) - Coordinates federal and federally-assisted borrowing. FFB is a self-supporting agency.
Federal Power Act - Enacted in 1920, and amended in 1935, the Act consists of three parts. The first part incorporated the Federal Water Power Act administered by the former Federal Power Commission, whose activities were confined almost entirely to licensing non-Federal hydroelectric projects. Parts II and III were added with the passage of the Public Utility Act. These parts extended the Act’s jurisdiction to include regulating the interstate transmission of electrical energy and rates for its sale as wholesale in interstate commerce. The Federal Energy Regulatory Commission is now charged with the administration of this law.
Federated cooperative - A cooperative composed of smaller cooperatives.
Feeder lines - Main distribution lines that carry electricity from a substation.
Filed tariff - Rates and rules filed with the Federal Energy Regulatory Commission.
Finding of No Significant Impact statement (FONSI) - A document from the Federal Rural Utilities Service stating that a given project will have no significant impact on the environmental, cultural, historical or archeological resources of the area affected; necessary before a project funded by the Rural Utilities Service can be processed.
Firm energy - The amount of electric energy that is certain to be available at all times from any given plant or system, or under any given contracts, even under adverse conditions such as when a given plant is out of service. Also known as firm power.
Firm gas - Gas sold on a continuous and generally long-term contract.
First in, first out - A method of retiring capital credits where the earlier credits are retired first.
First mortgage bonds - Certificates of indebtedness representing the long-term borrowing of capital funds for utility needs.
Fission - The process whereby a nucleus of an appropriate type, after capturing a neutron, splits into (generally) two nuclei of lighter elements, with the release of substantial amounts of energy (heat) and two or more neutrons.
Fixed costs - Costs associated with investment in plant. A distribution cooperative’s “fixed costs” would be such items as rent, light, heat, taxes and depreciation on buildings, lines and equipment. These costs are constant regardless of the level of kilowatt-hour sales or other expenses.
Flashover - An abnormal electrical discharge, as from a high-voltage power line to a ground.
Flat rate - This is a single rate where consumers pay the same rate for each kilowatt-hour of electricity used.
Flip-flop - Practice of changing from one electric utility to another, usually due to rate differences. This practice is illegal in some states but weak laws make it difficult to enforce.
Flue gas - The mixture of gases and fly ash escaping from a coal fired boiler. (See pollution control)
Flue gas desulfurization unit (scrubber) - Equipment used to remove sulfur oxides from the combustion gases of a boiler plant before discharge to the atmosphere. Chemicals, such as lime, are used as the scrubbing media.
Flue gas particulate collectors - Equipment used to remove fly ash from the combustion gases of a boiler plant before discharge to the atmosphere. Particulate collectors include electrostatic precipitators, mechanical collectors (cyclones), fabric filters (baghouses) and wet scrubbers.
Fluidized-bed combustion - A method of burning coal to achieve lower emissions by combining coal with limestone or other similar material held in suspension by air moving upward through the boiler.
Fly ash - Tiny particles of solid ash in smoke when fuels (such as coal) are burned.
FONSI - Finding of No Significant Impact statement.
Foot-candle - The illumination of a surface one-foot distant from a source of one candela, equal to one lumen per square foot. Also called “candle-foot.”
Forced outage - The period of time during which a power plant is scheduled to operate but is unable to do so because of breakdowns or other unforeseen circumstances.
Fossil fuel - Materials such as coal, oil, and natural gas which are also called conventional fuels. Alternatives include hydro (water), solar (sun), nuclear, wind, geothermal (derived from heat contained deep inside the earth) and other energy sources.
Fossil fuel plant - A plant using coal, petroleum, or gas as its source of energy.
Frequency - The number of cycles completed each second by a given AC voltage.
Frequency regulation - Activities necessary to maintain the alternating current cycling at 60 hertz. This is necessary for many reasons, such as keeping clocks on time.
Fuel - Any substance that can be burned to produce heat; also, materials that can be fissioned in a chain reaction to produce heat.
Fuel cells - Devices that convert the chemical energy of fuels directly into electricity.
Fuel cost - The total cost of fuel delivered to a power plant, including freight and other transportation charges, unloading costs and maintenance and mine reclamation costs. Also known as fuel expenses.
Fuel cost adjustment clause, fuel clause - A generating utility’s rates are set to recover various costs, including the cost of fuel. Fuel costs can change markedly from month to month. The regular rates contain a certain amount for basic fuel expenses. The fuel cost adjustment clause allows the utility to charge only for the actual cost of fuel above or below the basic fuel cost stated in the rate.
Fuel reprocessing (nuclear) - The processing of used reactor fuel to chemically separate the fuel into waste products, plutonium and reusable uranium.
Full-forced outage - The net capability of main generating units that is unavailable for load for emergency reasons.
Functional unbundling - Separately pricing all wholesale generation and transmission services (including ancillary services) and taking wholesale transmission service under a utility’s own tariff.
Fuse - A circuit interrupting device used to protect against excessive current flow in conductors. A metal link in the fuse will melt (the fuse “blows”) and breaks the circuit when the current becomes excessive. When this metal link melts, the fuse is destroyed and cannot be reused.
Fusion (nuclear) - The formation of heavier nuclei from two lighter ones, resulting in a release of energy.
Futures contract - (trading technology) Legally binding commitment to buy or sell a particular amount of a commodity at a specified location at a future date for the price set today.
GGAO - General Accounting Office.
Gas - A fuel burned under boilers and by internal combustion engines for electric generation. These include natural, manufactured and waste gas.
Gas turbine - An electric generating station where the generator is driven by a gas turbine engine.
Generating unit - Any combination of physically connected generator(s), reactor(s), boiler(s), combustion turbine(s), or other prime mover(s) operated together to produce electric power.
Generation - Producing electricity by power plant or machine.
Generation company (Genco) - An entity that operates electricity generating plants. The Genco may own the generation plants or interact with short-term marketers on behalf of plant owners.
Generation, Gross - The total amount of electric energy produced by the generating units at a generating station or stations, measured at the generator terminals.
Generation, net - Gross generation less the kilowatt-hours consumed to operate the generating station.
Generation station (power plant) - A plant that has generators and other equipment for producing electricity.
Generation & Transmission Cooperative (G&T) - A cooperative, which generates electricity and transmits it to distribution cooperatives.
Generator - A machine that transforms the mechanical energy of a rotating shaft to electric energy.
Geothermal energy - Natural heat contained in the rocks, hot water and steam of Earth’s subsurface; can be used to generate electricity and heat homes and businesses. Energy from the internal heat of Earth.
Geothermal power - Electricity made by a generator powered by steam or hot water trapped and warmed below Earth's surface by Earth’s internal heat.
Geothermal system - An efficient electrical device for heating and cooling a home or other building by moving heat into or out of the structure. It uses an antifreeze solution or refrigerant in a pipe buried in the ground to collect or disperse heat. (See earth-coupled heat pump, ground-source heat pump, heat pump, water-source heat pump)
Gigawatt (GW) - One million kilowatts (one billion watts).
Gigawatt-hour (GWh) - One thousand megawatt-hours (one billion watt-hours).
Global warming - A gradual warming of Earth’s atmosphere reportedly caused by the burning of fossil fuels and industrial pollutants.
Green Power - A term, which refers to production of electricity using renewable sources such as wind, hydroelectric or crop residue.
Greenhouse effect - A global warming trend caused by the trapping of heat in Earth’s atmosphere due to rising amounts of carbon dioxide and other gases.
Greenhouse gases - Carbon dioxide and other gases that reportedly contribute to the warming of the Earth's atmosphere.
Grid - A system of interconnected high-voltage transmission lines and power generating facilities that allows bulk-power suppliers to share resources on a regional basis. This system provides emergency generation and transmission by transmitting power from areas having a surplus to areas experiencing a shortage. The creation of a national grid has been proposed.
Gross energy demand - The total amount of energy consumed by direct burning and indirect burning by utilities to generate electricity. “Net energy demand” includes direct burning of fuels and the energy content of consumed electricity. The difference between “gross energy demand” and “net energy demand” is a measure of the energy losses by utility conversion to electricity. About two-thirds of the energy input at the utility is lost in generation and transmission.
Ground - A conducting path between an electrical circuit or equipment and the Earth. In alternating current systems, the purpose of grounding is for safety. If proper grounding is not maintained, risk of electrical shock, fires, and damage to appliances and motors greatly increases. A ground is often established using a conducting rod driven into the earth.
Ground fault circuit interrupter (GFCI) - A protective device that disconnects when it measures a 5 mili-amp difference between the neutral and the ground. It cuts the current almost instantaneously to provide shock protection. GFCIs are available for permanent installation at the service entrance or convenience outlets and as portable protective devices for operating portable tools and appliances.
Ground rod - A metal rod driven into the earth to serve as a ground terminal.
Ground-source heat pump - An efficient electrical device for heating and cooling a home or other building by moving heat into or out of the structure. It uses an antifreeze solution in a pipe buried in the ground to collect or disperse heat (see earth-coupled heat pump, geothermal system, heat pump, water-source heat pump).
Guaranteed loan - A loan that a third party agrees to repay if the borrower defaults; the Rural Utilities Service acts as the third party for some electric cooperatives.
Guy - A tension wire that adds strength to an electrical pole.
HH-frame - A wood structure composed of two poles connected by a cross arm near the top. Transmission lines are constructed either of aluminum or copper wires. These wires are carried on either steel towers or wood pole structures.
Harmonic - An oscillation whose frequency is a multiple of the normal frequency. Example: Third harmonic is equal to 180 hertz, since normal frequency in the U.S. is 60 Hz.
Harmonic distortion - Harmonics are distortions of the standard sine-wave in which electricity travels. Harmonics are transmitted back into the individual circuit wires by nonlinear loads (equipment that doesn’t draw power in regular sine-waves) such as computers, copiers, fax machines and variable speed motors.
Head - The depth of water in a hydroelectric plant reservoir that is above the level of the plant’s turbines. High heads (those of 65 or more feet) are more feasible producers than low heads, because they provide more water pressure with which to produce power.
Heat pump - A system supplying both space heating and cooling. The heat pump removes heat from the outside air and pumps it indoors. The heat pump can also function as an air conditioner, absorbing heat from indoors and releasing it to the outside.
Heating seasonal performance factor (HSPF) - The total heating output of a heat pump during its normal annual usage period for heating divided by the total electric power input in watt-hours during the same period.
Heavy oil - The fuel oils remaining after the lighter oils have been distilled off during the refining process. Except for start-up and flame stabilization, virtually all petroleum used in steam plants is heavy oil.
Hertz - Unit of frequency equal to one cycle per second. Frequency is standardized in the U.S. at 60 cycles per second, being the same as 60 hertz.
High head hydro - (see head)
High voltage - Voltage in a power line higher than the 110 to 220 volts used in most residences.
Horsepower (hp) - A measure of the work performed by one horsepower exerted for one hour.
Horsepower-hour - A measure of power equal to about 746 watts. Always spell out.
Hot leg - A conductor that normally operates at a voltage above ground.
House Energy and Commerce Committee (HECC) - HECC has jurisdiction over legislation on electric utility regulation, federal power administration, and energy plant siting (including nuclear facilities).
Hydro - A term used to identify a type of power, generating station or energy output where the prime mover is driven by water power. Also called a hydroelectric plant.
Hydroelectric generating station - A generating station where the generator is driven by a water wheel.
Hydroelectricity - Producing electricity by water power, usually falling water that turns a turbine.
IIBEW - International Brotherhood of Electric Workers.
IEEE - Institute of Electrical and Electronic Engineers, Inc.
Impedance - The combined effect of resistance, inductance and capacitance on current flow.
Impulse - A short (much less than one-half cycle) increase in voltage.
Incentive rate - A discount offered to encourage consumption or appliance usage during a desired time interval. For example, off-peak, time-of-use, interruptible, dual-fuel heating rates are all types of incentive rates. They are designed to limit usage during the on-peak periods and encourage consumption during the off-peak periods. Electric companies use incentive rates to encourage a change in consumption patterns.
Incremental cost - The incremental cost (or marginal cost) represents the cost of an additional unit. This may be an additional residential consumer or an additional load.
Independent power producer (IPP) - A private entity that generates electricity and sells it to other businesses, including utilities.
Independent system operator (ISO) - The independent operator of a transmission system, responsible for guaranteeing open access, scheduling, system reliability and accounting.
Independent Transmission Company (ITC) – A for-profit company that owns transmission assets through, for example, divestiture or long term leasing. Another form of a regional transmission organization.
Inductance - A physical property of all AC circuits that opposes a change in current; measured in henrys.
Induction - The production of an electric current by passing a wire through a magnetic field or production of current by the changing level of an electrical field on a stationary wire or object.
Inductive reactance - The measure of the opposition to current that is created by inductance: measured in ohms.
Industrial customer - A company in a manufacturing business.
Industrial rate - An industrial rate is simply a rate designed for the industrial customer classification. It may refer to a single large consumer or to several large consumers having similar plant and consumption requirements.
Information superhighway - A term used to describe the flow of information through computer connections, the Internet and other high-tech devices.
Inrush current - The initial current when an electric coil or motor is energized. Often the initial current is equal to six times the normal current.
Institute for Nuclear Power Operations (INPO) - Charged with the responsibility of establishing standards of excellence for plant operations, evaluating the performance of utilities against these standards, and assisting utilities in improving plant safety and reliability.
Institute of Electrical and Electronics Engineers, Inc. (IEEE)- Develops standards on definitions, test methods, symbols, units and safety in the field of electrical science and engineering.
Insulator - A nonconductor, usually of glass or porcelain, for insulating and supporting electric wires.
Insured loan - Money lent to a rural electric cooperative by the Rural Utilities Service through the Rural Electric and Telephone Revolving Fund.
Integrated Gasification Combined Cycle (IGCC) - An Integrated Gasification Combined Cycle, or IGCC, is a power plant using synthetic gas (syngas).
Interchange agreement - An agreement that can include a variety of services utilities provide each other to increase reliability and efficiency and to avoid duplicating expenses. Some examples are: transmission service (the use of transmission lines to move power from one area to another); emergency services (an agreement by one utility to furnish another with power to protect it in times of emergency, such as power plant breakdowns); reserve sharing (when utilities contribute to a common pool of generating plant reserves so each individual utility’s reserves can be reduced); and economic exchanges (when utilities swap power out of various plants to avoid running their most fuel-expensive units).
Interconnection agreement - An agreement between two utilities to connect their transmission systems. Once interconnected, the utilities may enter into interchange agreements.
Intermediate plant - Also known as a “cycling plant,” this is a generating station smaller than a base-load station and intended for less than 24-hour use. Such plants are used only when demand rises, then are dropped out of service as demand falls.
Interruptible rates (or load management) - Arrangements in which a utility offers a lower rate in return for the ability to curtail service during peak demand periods. These arrangements permit the utility to reduce load by interrupting service as agreed upon.
Interruptible service - Electric service which may be stopped at the supplier’s discretion or in accordance with a contractual agreement.
Interstate Commerce Commission (ICC) - Federal agency regulating interstate surface transportation, including railroads, trucks, buses and household movers.
Inverted rate - A rate schedule in which the charge per kilowatt-hour increases with higher levels of use.
Investor-owned utility (IOU) - Utilities that generate and distribute electrical energy for a profit.
Isolator - A device designed to isolate the primary neutral from the secondary neutral (sometimes incorrectly called a blocker).
JJacket - A protective covering over the insulation, core, or sheath of an electrical cable.
Joint use - Simultaneous use by two or more kinds of utilities. This can be done by attachments to poles or through plowing underground cable of various types (example: electrical and telephone service) in at the same time, using the same right-of-way corridor.
Joule - A unit of work and energy. (symbol J) It is defined as the work done (energy transferred) in one second by a current of one ampere at a potential difference of one volt. One watt is equal to one joule per second.
Journeyman lineman, line worker - An electrical line worker who has completed apprenticeship training and has learned the trade of constructing and maintaining electric power transmission and/or distribution systems.
Junction box - An enclosure for the connection or branching of one or more electrical circuits.
KKey account - Any cooperative load deemed vital to the financial well being of the cooperative.
Kilovar (KVAR) - Equals 1,000 reactive volt-amperes. Reactive power is that party of “apparent power” that does not do work.
Kilovolt (kV) - One kilovolt is equal to 1,000 volts. The amount of electric force carried through a high-voltage transmission line is measured in kilovolts. The standard voltage for use in the home is 120 volts. For long transmission purposes, the voltages go as high as 1,000,000 volts. (1,000 kV)
Kilovolt-ampere (kVA) - One thousand watts (volt-amperes). The volt-amperes of an electrical circuit are the mathematical product of volts and amperes of a circuit.
Kilowatt (kW) - The basic unit of electrical demand, equal to 1,000 watts. The average household demand is 10 to 20 kilowatts.
Kilowatt-hour (kWh) - The basic measure of electric energy generation or use. A unit of energy or work equal to 1,000 watt-hours. (One kilowatt-hour is the amount of electric energy required to operate a 100-watt bulb for ten hours.)
Kilowatt-hour meter - The device used to measure electrical energy use.
LLatent cooling load - The net amount of moisture added to the inside air by plants, people, cooking, infiltration, and any other moisture source. The amount of moisture in the air can be calculated from a combination of dry-bulb and wet-bulb temperature measurements.
Least-cost planning - Efforts by utilities and regulators to meet growing power needs without building new plants. Methods include buying power from other utilities, making maximum use of transmission grids and developing conservation programs.
Leg - A trade name to describe an ungrounded (hot) conductor.
Lifeline rates - Establish a minimum number of kilowatt-hours required for subsistence and provide a below cost rate for this amount of usage. The rate would not be subject to increases, and the resulting subsidy would be made up by larger users. Lifeline rates have been suggested as a means of helping low-income customers.
Light oil - Lighter fuel oils distilled off during the refining process. Virtually all petroleum used in internal combustion and gas-turbine engines is light oil.
Lightning arrestor - A device that protects equipment from the destructive effects of lightning or voltage surges that strike power lines and antennas during electrical storms, by discharging or bypassing the surges.
Lignite - A low-sulfur, low-energy coal, found primarily in the upper Great Plains.
Limit switch - A mechanically operated device that stops a motor from revolving, or reverses it, when certain limits have been reached.
Line - A carrier of electricity on an electric power system, a conductor or wire used in a power system.
Line current - The current that flows through the wires in a three-phase system.
Line transformer - This device changes the voltage from the primary distribution voltage to the secondary distribution voltage required by the power customer.
Line side or load side - The line side is the supply side of any equipment, such as the power to the switch. The load side is the conductors leaving a switch. When referring to services, the line side is referred to as the supply side.
Line voltage - The voltage that is applied to the wires in a three-phase system.
Line loss - Electrical energy lost in the process of transmitting over power-lines.
Lineman, line worker - A person who builds and maintains electric lines (power transmission and/or distribution systems). May or may not have completed an apprenticeship program. To avoid sexist references, use line worker.
Live - Energized. A shock hazard exists.
Live parts - Electric conductors, buses, terminals, or components that are not insulated or exposed and a shock hazard exists.
Load - The amount of power drawn from an electric system at a specific time, or the total power drawn from the system. Peak load is the amount of power drawn at the time of highest demand. Also, anything that uses electrical energy.
Load control - (see load management, interruptible rate)
Load curve - A graph used to show how the use of electricity rises and falls during a given period of time.
Load diversity - The variation in electric usage among customers in a given area over a given time. Since not all users consume their maximum amount at the same time, there is diversity.
Load factor - The ratio of average demand/load to peak demand/load. A high load factor is better than a low load factor because it means the electrical system is being used closer to its full capacity at all times.
Load forecasting - Predicting a system’s load and kilowatt-hour sales growth.
Load leveling - Any practices which increase baseload generation. Peak load pricing and time-of-day charges are two techniques that electric utilities use to reduce peak load and to maximize efficiency in the generation of electricity.
Load management - A program by which an electric system seeks to control its customers’ use of electricity (or “loads”) so as to reduce the system’s total demand at a time of maximum (peak) usage. Load management can involve such techniques as voltage reduction, shutting off air conditioners and water heaters for short periods of time by remote control, controlling the time-of-day usage, rotating blackouts, rate structures, etc.
Load shedding - Curtailment of electrical service to pre-selected customers or areas, when available power is insufficient to meet the total system demand.
Loop transmission system - System in which alternate transmission lines can deliver power to an area in the event that lines fail.
Long hedge - (trading terminology) Involves a commitment to purchase a commodity in the future at a fixed price.
Long-term debt - Debts which include outstanding mortgage bonds, debentures, advances from associated companies, and notes that are due one year or more from the date of issuance. Securities that are due within one year of the date of the balance sheets are usually reported under “current and accrued liabilities.”
Loss control - Program for preventing or limiting financial and personnel loss from accidents.
Losses - Power (kilowatts) and energy (kilowatt-hours) lost during the operation of an electric system. Losses occur principally when energy is transformed into wasted heat in conductors and other apparatus.
Low head hydro - (see head)
Lug - A terminal device for terminating a conductor.
Luminaire - A complete lighting unit consisting of lamp or lamps, together designed to distribute light.
Lumen - The amount of light passing through an area per second. The lumen is defined in terms of the light falling on a unit area at a unit distance from a light source of luminous intensity of one candela.
MM & S - Market and supplies.
MAAC - Mid-Atlantic Area Council.
MAPP - Mid-Continent Area Power Pool.
Margin - The difference between a cooperative’s income and its expenses; returned to members in the form of capital credits as the cooperative’s financial status allows.
Margin stabilization - Refers to the adjustment of revenue to smooth margin levels over a period of time. Similar cost stabilization objectives can be accomplished with capital credits.
Marginal cost - The change in total costs associated with a unit change in quantity supplied. (i.e. demand or energy)
Marginal cost pricing - A method of determining the selling price of a commodity when the fixed costs are paid by units already sold so that the next units can be sold for less.
Maximum demand - The greatest of all demands on the load that has occurred within a specified period of time.
Maximum drawdown - A term used in connection with hydroelectric plant sites. Meaning the lowest reservoir level that would occur during the most critical dry period. (See head)
Mcf - One thousand cubic feet.
Megawatt (MW) - One million watts (1,000 kW).
Megawatt-hour (MWh) - One million watt-hours (1,000 kWh).
Member - In an electric cooperative, the customers are referred to as “members” because they share in the benefits and responsibilities of joint ownership.
Meter - A device that measures the amount of electricity used. Often used as a short form for a specific type of meter, for example: a kilowatt hour meter, a voltmeter, etc.
Mid-Continent Area Power Pool (MAPP) - An organization of power suppliers in the Upper Midwest that plans for power availability by coordinating power exchanges between members. MAPP’s members include investor-owned companies, municipal systems, electric cooperatives and the federal government’s Missouri Basin hydroelectric system.
Mid-West Electric Consumers Association - A lobbying and planning organization of more than 340 consumer-owned electric utilities and federal power organizations in the nine-state Missouri River drainage basin, formed to obtain dependable low-cost electric power. Use short form, Mid-West, on second reference; do not use acronym MECA.
Mil - A unit of length equal to 1/1000 of an inch, used in measuring the diameter of wire.
Mill - One tenth of a cent; a common utility industry monetary measure.
Milliampere (mA) - Equal to 1/1000 of an ampere.
MinnElecTrans – MinnElecTrans is a short-hand term used to describe the process under which utilities that own and/or operate electric transmission facilities in Minnesota hold public meetings, prepare and receive information, review and develop facility alternatives and otherwise meet their transmission planning requirements under Minnesota law.
Minnesota Association of Cooperatives (MAC) - A non-profit Minnesota association for cooperatives. Basic goals of MAC are to promote the common interests of cooperatives in legislation, government policy, public understanding and cooperative education, encourage and support farmer marketing, supply and service cooperatives, and encourage and support consumer housing, insurance and credit cooperatives.
Minnesota Public Interest Research Group (MPIRG) - State chapter of the Nader-founded Public Interest Research Group. A consumer/environmental group whose members are mostly young people (financed largely by student fees). It has challenged utilities in the areas of nuclear safety, advertising, rates and pollution control.
Minnesota Rural Electric Association (MREA) - A nonprofit, dues-supported association of electric distribution cooperatives and G&Ts. Formed to provide services (educational, loss control, legislative, etc.) which they would otherwise be unable to provide for themselves as individual entities. Overseen by a board of 12 directors elected by and from the membership, and a general manager hired by the board.
MISO – Midwest Independent Transmission System Operator
Modulation - Alteration in waveform frequency or amplitude due to superimposition of another wave or signal.
Motor - A device that transforms electric energy into mechanical energy, especially one that produces motion by means of a coil of wire around armature turning between poles of a magnet.
Motor Control Center - An assembly of one or more enclosed sections having a common power bus and principally containing motor control units.
Municipal (muni) - Electric system owned by a city or other government entity to provide service for the people living within its boundaries. Also referred to as a municipal public utility.
Mutual inductance - Interactive inductance between inductive circuit elements.
NNameplate rating - The rated capacity of a generator or other piece of equipment, under conditions specified by the manufacturer and usually indicated on a nameplate attached to the unit.
National Ambient Air Quality Standards - Levels of pollutants that can be present in the atmosphere without endangering public health and welfare; established by the Environmental Protection Agency.
National Association of Regulatory Utility Commissioners (NARUC) - Membership includes state and federal regulatory commissioners that have jurisdiction over utilities, motor carriers, and common carriers.
National Electrical Code (NEC) - The purpose of the Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.
National Electrical Manufacturers Association (NEMA) - The national trade association for manufacturers of equipment and apparatus used for the generation, transmission, distribution and utilization of electric power, such as electrical machinery, motors, transportation, communication and lighting equipment. NEMA also sets standards for the industry.
National Rural Electric Cooperative Association (NRECA) - A national service organization representing approximately 1,000 rural electric cooperatives in the United States, headquartered in Arlington, Va.
National Rural Telecommunications Cooperative (NRTC) - An organization formed to provide satellite TV programming to rural electric members.
National Rural Utilities Cooperative Finance Corporation (CFC) - A private cooperative corporation owned by rural electric cooperatives and used for supplemental financing by electric cooperatives.
National Telephone Cooperative Association (NTCA) - The Washington, D.C.-based service organization that represents about 450 telephone cooperatives and other independent telephone companies in the United States.
National Utility Training and Safety Education Association (NUTSEA) – An organization whose primary activities are job training, safety education and safety-program administration for electric cooperatives and related organizations.
Natural gas - A fossil fuel used for electric generation and space heating.
Natural monopoly - A situation where one firm can produce a given level of output at a lower total cost than possible through competition.
Negative power - Power that is returning to a power source from a load.
Negawatt - Energy not produced by means of energy and capacity conservation. Recently the term has been improperly used to describe a situation were a large industrial plant(s) contracts with its power supplier to shut down operations and to sell the power elsewhere.
NERC - See North American Electric Reliability Council.
Net capability (capacity) - The maximum load-carrying ability of the equipment, exclusive of station use, under specified conditions for a given time interval, independent of the characteristics of the load. (Capability is determined by design characteristics, physical conditions, adequacy of prime mover, energy supply, and operating limitations such as cooling and circulating water supply and temperature, headwater and tailwater elevations, and electrical use.) Used synonymously with capacity.
Net generation - Gross generation minus plant use from all electric utility owned plants. The energy required for pumping at a pumped-storage plant is regarded as plant use and must be deducted from the gross generation.
Net metering - Measuring, through more than one meter or metering element, the energy supplied by the utility and a customer’s distributed generation facility.
Net metering, “Pure” - Measuring through one meter the net difference between energy supplied by the utility and a customer’s distributed generation facility.
Net summer capability - The steady hourly output, which generating equipment is expected to supply to system load exclusive of auxiliary power, as demonstrated by tests at the time of summer peak demand.
Net winter capability - The steady hourly output, which generating equipment is expected to supply to system load exclusive of auxiliary power, as demonstrated by tests at the time of winter peak demand.
Neutral conductor - A grounded conductor that permits the use of line to neutral loads (120 and 277 volt loads), and will serve as a current-carrying conductor to carry any unbalanced currents and provide a low impedance path for the flow of fault current to facilitate the operation of the over-current protective devices.
Neutral-to-earth voltage - Voltage that exists between the system neutral (grounded conductor) and earth. Also called stray voltage.
New generation cooperative (NGC) - A term that has been applied to the dozens of value-added, selected-membership cooperatives that have recently formed in the nation’s agricultural sector. They offer members the linking of producer capital contributions and product delivery rights.
Nipple - Conduit pipe less than two feet in length, may be either straight or angled.
Nitrogen oxides - Compounds of nitrogen and oxygen formed when fossil fuels burn.
Nitrous oxide - A gaseous emulsion which comes from sources such as automobile emissions and other fossil burning sources, as well as natural sources (such as electrical storms).
Noise - High-frequency interference. May be caused by radio or TV signals, light dimmers, microwaves, lightning, computer power supplies, improper grounding, loose hardware or equipment. It may also be caused by sources other than those listed.
Non-coincident demand - (see demand)
Non-firm - A sale of power to a consumer that can be stopped any time, for any reason, with no further commitment of service.
Non-linear load - A load where the wave shape of the steady-state current does not follow the wave shape of the applied voltage.
Non-power services - Includes such services as gas, home security and telecommunications.
Non-profit - Business not entered into for the purpose of making money.
Non-traditional pricing - Creative and flexible mechanisms for energy services designed to retain load, attract new users, and better reflect costs.
Norris-Rayburn Act - Legislation introduced in 1936 by Senator George Norris and Representative Sam Rayburn that continued the Rural Electrification Administration for 10 years as an independent lending agency.
North American Electric Reliability Corporation (NERC) - Formed by the electric utility industry in 1968 to promote the reliability and adequacy of bulk power supply in the electric utility systems of North America. NERC consists of nine Regional Reliability Councils encompassing virtually all of the power systems in the United States and Canada.
Northeast Power Coordinating Council (NPCC) - One of nine regional electric power planning and pooling organizations that are members of the North American Electric Reliability Council.
Nuclear energy - Energy released in the form of heat during the fission process, which takes place in a nuclear reactor containing a core of nuclear fuel, primarily uranium. When released in sufficient and controlled quantity, this heat energy may be used to produce steam to drive a turbine-generator thereby producing electricity.
Nuclear fission - The splitting of an atomic nucleus, resulting in the release of large amounts of energy; the basic process a nuclear reactor uses to provide heat for the generation of electricity.
Nuclear fuel - Materials containing fissionable substances of such composition and enrichment that, when placed in a nuclear reactor, sustain a chain reaction.
Nuclear fuel assemblies - Fabricated forms of fissionable material and other materials used in reactors to facilitate the fission process.
Nuclear fuel costs - Nuclear fuel costs generally are given on a fuel cycle basis. A fuel cycle consists of all the steps associated with the procurement, use, and disposal of the fuel during its lifetime, a period of about five to six years. Costs may also include interest charges.
Nuclear fusion - The combination of two light nuclei to form a heavier nucleus with the release of some binding energy.
Nuclear generating station - An electric generating station where the generator is driven by a steam turbine. This steam is generated in a reactor by the heat produced from nuclear fission.
Nuclear power - Electric energy generated using heat produced by an atomic reaction. (See nuclear fission, nuclear fusion)
Nuclear radiation - Invisible particles or waves given off by radioactive materials such as uranium.
Nuclear reactor - An apparatus in which the nuclear fission process is initiated, maintained, and controlled. A commercial reactor has four essential parts: (1) a core which houses the nuclear fuel assemblies, (2) a control system which regulates the rate of fission and thereby the rate of heat generation, (3) a water cooling system that carries heat from the fuel assemblies, and (4) additional cooling systems and protection barriers.
Nuclear Regulatory Commission (NRC) - The federal agency responsible for the licensing and safety of nuclear power plants. The NRC is the successor to the Atomic Energy Commission.
OOCR - Oil-circuit recloser.
OHD - Overhead
Occupational Safety and Health Administration (OSHA) - Department of Labor agency that sets standards for safe work places and enforces them through periodic inspections.
Off-peak - Period of relatively low demand on the company’s electric system.
Off-peak power - Power supplied during designated periods of relatively low system demands. (See demand)
Off-peak rates - Special lower rates for electricity used at the times of low system demand.
Office of Management and Budget (OMB) - A federal office, that is part of the administration, in charge of all federal revenues and expenditures.
Offset rate - Rate adjustment that allows a system to pass along certain changes to consumers.
Ohm - A unit measuring electrical resistance.
Ohm’s Law - The strength of an unvarying electrical circuit is directly proportional to the resistance of the circuit. In other words, voltage is equal to current multiplied by resistance. Use the following formula: E=IxR, where E is voltage in volts, I is current in amps, and R is resistance in ohms.
Oil-circuit recloser - A cutout in which all or part of the fuse support and its fuse link or disconnecting blade is mounted in oil with complete immersion of the contacts and the fusible portion of the conducting element (fuse link) so that arc interruption by severing of the fuse link or by opening of the contact will occur under oil.
On line - Generally used to indicate when a generating plant is scheduled to be in operation. When an operational plant is not on line, it is said to be “down.”
On-peak - Energy supplied during periods of relatively high system demands as specified by the supplier.
Open transmission access - the ability of a utility to purchase power from another utility or independent power producer and move it over transmission lines that belong to a utility not involved with the purchase, made possible through the Energy Policy Act of 1992.
Operating expenses - The costs to a utility of generating electricity. In addition to costs of running a plant, includes maintenance expenses, taxes and depreciation.
Operating income - The amount of income remaining after operating expenses are deducted from operating revenues.
Operating revenues - Money received from selling a utility’s goods and services.
Oscilloscope - An instrument that uses a cathode-ray tube to display waveform images of periodic changes in voltage or current.
Outage - Interruption of service to an electric consumer.
Over-current - Any current in excess of the rated current of the equipment or the ampacity of a conductor.
Overhead - Pertaining to conductors and other power delivery equipment that is located on poles, towers, and other above ground structures.
Overload protection - A device that opens as a result of excessive current, but not short circuit or ground-fault current. A current that is not more than six times the rated current for alternating current motors.
Ozone layer - The part of the upper atmosphere that contains concentrations of a form of oxygen that screens out ultraviolet radiation.
PPace Act - Law extending the life of the Federal Rural Electrification Administration (now Rural Utilities Service) indefinitely beyond the target expiration date of 1946; also set RUS interest rates at 2 percent and lengthened loan terms to 35 years.
Pad-mounted equipment - Enclosed equipment, the exterior of which is at ground potential, positioned on a surface-mounted pad.
Pancaking of rates - 1) When a utility places a new wholesale or retail rate increase into effect on top of an older rate increase that has not yet received final approval by the proper government agency. 2) Refers to the accumulation of transmission payments to multiple transmission owners as electricity crosses from one transmission line to another.
Parallel circuit - An electrical circuit that has positive and negative terminals connected to two distinct points, with voltage applied equally throughout
Parallel path flow - The capacity of power lines distant from an individual transaction, using an interconnected system, to carry a part of the power being transferred between two utilities.
Partial-requirement customer - An electric system that purchases only part of its electric power from a single utility. Additional power requirements are met by self-generation, or by purchasing power from a separate supplier.
Passive solar energy - Solar radiation collected without the use of complicated and highly technical equipment. Design and orientation are the main concepts of passive solar energy collection.
Patronage capital - Capital furnished by the patrons in connection with payments for electric service.
Peak demand - The maximum amount of electricity used by a utility customer at any time during the year. The peak is used to measure the amount of electric transmission, distribution, and generating capacity required to meet that maximum demand.
Peak load plant - A power plant which is normally only operated to provide power during maximum peak load periods.
Peak shaving - Cutting down electrical consumption during peak demand periods.
Peaking unit - Part of an electric generating plant used only at high-use periods to provide sufficient electric capacity for the system to meet its peak demand.
Peak-load pricing - A peak-shaving power plant may be operated a few hours a year to help meet a utility’s maximum (peak) demand. By running a peaking plant, a wholesale customer can reduce its power costs, not only at the time of the actual peak but also in succeeding months.
Peak-to-peak value - The amount of voltage or current represented by the distance between the positive peak and the negative peak on a sine wave.
Percentage method - Retirement of capital credits to members by paying a portion of all capital credits in a memberıs account, and ignoring the time the money has been in the account.
Performance regulation - Regulation based on measurements of key indicators. Standards are put in place and the regulatory system rewards or punishes the company based on how well the company met the standards. Currently, IOU rates of return are based on measurement of how much investment is made.
Perm - Unit of measurement for the rate at which water moves through a membrane. Used to measure vapor barriers in home construction and remodeling.
Phase current - The current that flows through the coils or resistors in a three-phase system.
Phase voltage - The voltage that is applied across the resistors or induced in the coils of a three-phase system.
Photoelectric cell - A cell whose electrical properties are modified by illumination by light waves.
Photovoltaics - Technology that produces electric power directly from sunlight. A common application is in solar-powered pocket calculators, but various equipment remote from electric distribution lines also uses the technology.
Plenum - A compartment to which one or more air ducts are connected and that forms part of an air distribution system.
Plug-in, plug in - Use with hyphen to mean a receptacle that supplies electricity to appliances. Used without the hyphen, it means the act of connecting an appliance to a receptacle.
Plutonium (Pu) - A heavy man-made radioactive metal. Its most important isotope is fissionable plutonium-239, which can be used for reactor fuel.
Pondage - Usable water storage at a hydroelectric site.
Polarity - Distinguishing one conductor or terminal from another. Identifying the positive conductor from the negative conductor or terminal.
Pollution control - Steps taken by rural electric cooperatives to ease any harmful environmental effects resulting from the production of electricity.
Polychlorinated biphenyls (PCBs) - A chemical that was used in insulating oil, commonly found in oil filled electrical equipment. No longer in common use. PCB is acceptable on all references.
Postage stamp rate - The combining of high cost and low cost power so that all members pay the same rate.
Potential - Work needed to bring a unit of positive charge from distance to given point.
Potential difference - The difference in electric force between any two points in a circuit, with current flowing from high to low level.
Power - The energy for doing work. The time rate of generating, transferring or using electric energy, usually expressed in watts.
Power cost adjustment (PCA) - The charge or credit on a consumer’s bill, which reflects the actual cost of wholesale power - above or below the base cost stated in the approved rate schedule. (See fuel clause adjustment)
Power factor - The ratio of real/true power (kilowatts) to apparent power (kilovolt-amperes) for any given load and time.
Power grid - A network of generation, transmission, and distribution systems that are interconnected.
Power line - A conductor carrying electricity from the generator to the supplier or the ultimate consumer. Two words.
Power marketer/broker - As a relatively new player in the electricity marketplace, power marketers and brokers are not utilities, but they work to match power buyers with power sellers and may own generation facilities from which they sell power to multiple buyers.
Power Marketing Administrations (PMAs) - The umbrella term for four federally owned PMAs that sell power produced at federal hydropower projects, giving first priority to consumer-owned systems such as co-ops or municipals and making that power available at the cost of production.
Power Marketing Agency (PMA) - A federal organization involved in delivering electricity from federal resources to purchasing utilities, such as the Western Area Power Administration (WAPA).
Power pool (electric) - Two or more electric systems which are interconnected and operated on a coordinated basis to achieve economies in supplying their combined loads. (See Mid-Continent Area Power Pool).
Power supplier (or electric energy supplier) - A company which supplies the actual energy either by generating it or by arranging for its delivery to the consumer.
Power theft - Stealing energy, usually by tampering with a meter to lower electric bills; a dangerous and illegal act.
Powerhouse - An electrical generating station.
Preference Principle - Legislative requirement giving non-profit consumer-owned electric systems first purchase rights to federal hydroelectric power generated on the nation's rivers and streams. Short-term is preferred; preference, acceptable on second reference.
Price Anderson Act - Federal legislation establishing a liability insurance program for nuclear power plant operations.
Price signal - Electric rates are considered price signals to consumers because they dictate how the consumer will use electricity and determine the type of investments in appliances and equipment they will make. A price signal is simply offering a cost discount to consume electricity during a desired period or a cost addition to discourage usage during another period.
Primary - The part of a devise or equipment connected to the power supply circuit.
Prime mover - An engine, turbine, water wheel, or similar machine that drives an electric generator; or, for reporting purposes, a device that converts energy to electricity directly (e.g. photovoltaic solar and fuel cell(s)).
Privatization - Turning over government or public assets, such as power marketing agencies, to private interests to be operated for profit.
Project SHARE - A program of the National Rural Electric Cooperative Association International Foundation, this project is designed to provide money, equipment and technical assistance to villages and communities in Third World countries that can not be helped under more formal arrangements. One aspect of the program sends them surplus equipment from U.S. cooperatives.
Public Authority Service to Public Authorities - Public authority service includes electricity supplied and services rendered to municipalities or divisions or agencies of State or Federal governments, under special contracts or agreements or service classifications applicable only to public authorities.
Public Power District - A political subdivision with territorial boundaries frequently covering more than one county for the purpose of generating, transmitting and distributing electric energy.
Public Utilities Commission (PUC) - A Minnesota legislative and quasi-judicial independent regulatory commission responsible for the administration of the Public Utilities Act. The PUC consists of five members who serve six-year terms. Appointments are made by the governor with the advice and consent of the Senate. No more than three of the five commissioners can belong to the same political party, and at least one member must be from outside the seven-county Metro area. There are no specific professional qualifications. The PUC is established in Chapter 216A of Minnesota Statutes.
Public Utilities Holding Company Act (PUHCA) - Federal legislation dating from the Great Depression designed to control corporate activities of investor-owned utilities.
Public Utility Regulatory Policy Act (PURPA) - One of five parts of the National Energy Act passed by Congress on October 15, 1978. It is concerned with voluntary rate standards, cogeneration, small hydro loans, interconnections and wheeling, and other regulatory policies. Pumped storage - A storage arrangement whereby water, which is pumped into a storage reservoir during off-peak periods, is used to generate additional electric power during peak-load periods.
Purchased power adjustment - A clause in a rate schedule that provides for adjustments to the bill when energy from another electric system is acquired and it varies from a specified unit base amount.
Pure pumped-storage - A plant that produces power only from water that has previously been pumped to an upper reservoir.
Put - (trading terminology) An options contract that gives the holder the right, but not the obligation, to sell futures at a specific period of time.
QQuad (quadrillion) - One quadrillion (1015) British Thermal Units (Btus). Equal to the energy contained in 8 billion gallons of gasoline, a year’s supply for 10 million cars.
Quorum - Number of members who must be present to conduct cooperative business legally.
RR-value - A measure of the ability of a substance or combination of substances (as building material or insulation) to retard the flow of heat, with higher numbers indicating better insulating properties.
Raceway - Any channel designed expressly and used solely for holding conductors.
Rad - A measure of the amount of radiation absorbed by the human body.
Radial feeder - A feeder supplying electric energy to a substation or feeder point that receives energy by no other means. Note: The normal flow of energy is such a feeder is in one direction only.
Radial line - The sole source of electric transmission feeding an area. In the event of transmission failure, the area has no alternate transmission system from which to receive electricity.
Radiant energy - Energy traveling outward from a source with a wave motion, such as the energy of electromagnetic waves.
Radiation - Energy emitted as electromagnetic waves or as nuclear particles; a natural component of the environment and an inevitable by-product of nuclear power. (See nuclear radiation)
Radiator - A device that transfers heat to the air in a room.
Radio control - A method by which the controlled load (water heater, air conditioner, irrigation pump, etc.) can be switched off or on via commands picked up by a radio receiver located at or near the load point. Switching signals are broadcast from one or more transmitters controlled by the utility.
Ratchet clause - A rate schedule clause which provides that maximum past or future demands shall be used in determining the billing demand for the entire year.
Rate - (see individual rate types, i.e. demand rate, interruptible rate, lifeline rate, seasonal rate, time-of-day rate, time-of-use rate, off-peak rate and on-peak rate)
Rate base - A utility’s rate base is the total value of its various
properties: power plants, transmission lines, buildings, fuel, stocks (if an IOU), etc. The utility is allowed, through its rates, to collect a percentage of profit or margin on the value of its rate base. This percentage of profit or margin (called rate of return) varies, but generally averages 5 to 13 percent, with the higher returns allowed for investor-owned companies.
Rate class - A group of customers identified as a class - for example, residential users - which are subject to a rate different from those of other groups.
Rate of return - The percentage of profit a utility may earn from its electric rates; generally, it applies only to investor-owned utilities regulated by a state agency.
Rate schedule - The category of electric rates used to charge customers for electric service. The two categories of electric rates are known as demand rates and metered rates.
Rate structure - The design and organization of billing charges by customer class to distribute the revenue requirements among customer classes and rating periods.
Ratemaking authority - A utility commission’s legal authority to fix, modify, approve, or disapprove rates, as determined by the powers given the commission by a state or federal legislature.
Reactive power - The portion of “Apparent Power” that does not work. Measured in kilovars, it must be supplied to most types of magnetic equipment, such as motors.
Reactor - A complex machine that heats water to boiling, producing steam to turn a turbine that generates electricity. The heat for boiling the water is produced by the fission, or splitting, of uranium atoms. (See nuclear fission)
Real power - The energy or work-producing part of “Apparent Power.” It is the rate of supply of energy, measured in kilowatts. The product of real power and length of time is energy, expressed in kilowatt-hours.
Rebate - A partial return of payment for equipment or appliances to consumers who meet specific requirements, such as installing energy saving devices like the ground source heat pump.
Reciprocity - Requiring the transmission user to supply the transmission provider with comparable transmission access and transmission services.
Reclamation - Restoring mined land to productive use; includes replacement of topsoil, restoration of surface topography, waste disposal, and fertilization and re-vegetation.
RECNET - A National Rural Electric Cooperative Association satellite television network that offers training and information programs for directors and employees of rural electric systems.
Rectifier - A devise used to change AC to DC.
Regional meeting - A gathering of rural-electrical leaders from states within one of 10 regions of the National Rural Electric Cooperative Association.
Regional Reliability Organization (RRO) - An organization that is charged with ensuring compliance with North American Electric Reliability Council standards and criteria. This organization is responsible for the safety and reliability of a region’s bulk electric system.
Regional Transmission Organization (RTO) - A regional organization that oversees transmission in a defined area and ensures access to the transmission grid. There are several models of an RTO, including an Independent System Operator (ISO), which is a non-profit organization that controls, but doesn’t own the power lines in its region. Another form of an RTO is an Independent Transmission Company (ITC), a for-profit company that owns transmission assets through, for example, divestiture or long term leasing.
Regulation - A government’s legal right to govern businesses.
Regulatory commission - A state or federal agency responsible for the activities of an industry or segment of an industry. In regard to the electric utility industry, most states have regulatory commissions that must approve service area, construction permits, financing, and rates. A majority of electric cooperatives are not regulated by their respective state commissions.
Regulatory compact - An agreement that has evolved over time between utilities and regulatory bodies, giving special privileges to utilities in return for meeting certain obligations.
Relative price of electricity - The price of electricity relative to the price of all other goods. For example, if the nominal price of electricity rose by 10 percent and all other prices rose by 20 percent, a drop in the relative price of electricity has occurred.
Reliability - A utility’s ability to deliver uninterrupted electricity to its consumers.
Rem - Abbreviation for roentgen equivalent man, a measure of radiation received by an individual. A dose of 100 rem will cause severe illness; 500 rem more is considered fatal.
Remote supplier - A utility, independent power producer, power marketer or broker that is not directly connected to the local distribution grid.
Reserve margin (operating) - The amount of unused available capability of an electric power system at peakload for a utility system as a percentage of total capability.
Reserves - The power reserve capacity above firm system load required to provide for: (1) regulations within the hour to cover minute-to-minute variations in demand, (2) load forecasting error, (3) loss of equipment and (4) area protections. It is the reserve capacity capability needed to ensure a specified standard of service.
Residential conservation service program (RCS) - The Department of Energy developed the RCS program in 1981 to encourage home energy conservation through the application of measures such as insulation and window caulking and the use of solar and wind energy systems.
Resistance - The opposition to the flow of electrical current from the material through which the current passes, expressed as ohms. All materials have electrical resistance. The two most important characteristics of resistance are: (1) heat is generated when electricity flows through a resistant material and (2) the voltage is decreased when electricity flows through a resistant material.
Restructuring - Changes in the electric utility industry as a result of deregulation trends. Also refers to the reorganization of an electric utility. Sometimes used interchangeably with the term deregulation.
Retail - Sales covering electrical energy supplied for residential, commercial and industrial end-use purposes. Other small classes, such as agriculture and street lighting, also are included in this category.
Retail competition - The ability for customers to choose the companies from which they buy all necessary electric power services. A customer may buy energy, efficiency, billing and meter reading services all from separate companies.
Retail customer - A consumer who uses electricity.
Retail wheeling - The ability of a retail customer to choose its power supplier, therefore requiring the use of another utility's transmission and distribution system to transmit the power. Also known as retail competition.
Retrofit - Installation or replacement of equipment at a plant after the plant has been built.
Revenue - The total amount of money received by a firm from sales of its products and/or services, gains from the sales or exchange of assets, interest and dividends earned on investments, and other increases in the owner’s equity, except those arising from capital adjustments.
Revenue protection - The process of eliminating losses that occur as a result of meter tampering, fraud, and theft of electric energy.
Revenue requirement - The revenue level necessary to achieve a specified rate of return.
Revolving Fund - A U.S. Treasury fund that lends money to rural electric and telephone systems. It is called a revolving fund because the money borrowers pay back on their loans is used to make new loans. Short form for Rural Electric and Telephone Revolving Fund. Acceptable on all references.
Right of way - Use of property covered by an agreement that allows utilities to construct and operate their facilities there. Sometimes acquired through the right of eminent domain. Plural is rights of way. Hyphenate when used as an adjective (i.e. right-of-way crew). (See easement, eminent domain)
Ripple control - The remote control of switching devices which uses power lines as signal carriers. A coded audio frequency “ripple” is superimposed onto the power lines at one or more injection point(s). This signal is detected by receivers situated at the loads to be controlled. Generally used for load management purposes.
Rural Electric Cooperatives (RECs) - Individual, consumer-owned, non-profit, electric cooperatives are located largely in the rural areas of the country. Rural people joined together to borrow money through the Rural Electrification Act of 1936 to build their own electrical systems and bring central-station electrical service to their farms and homes.
Rural Electric Political Action Committee (REPAC) - A voluntary political action group that supports candidates for state offices.
Rural Electric Statewide Managers Association (RESMA) - An organization of the managers of statewide rural electric associations around the country.
Rural Electric Supply Cooperative (RESCO) - RESCO buys in volume, warehouses, and distributes electrical supply items.
Rural Electric Youth Tour - An annual educational trip to Washington, D.C., organized by the National Rural Electric Cooperative Association and statewide associations for high school students selected by local rural electric systems. Short form is Youth Tour, acceptable on all references.
Rural electrification - A term used to describe the introduction of electricity to rural areas, unserved by power companies until then.
Rural Electrification Administration (REA) - 1935-1994 (see Rural Utilities Service)
Rural Telephone Bank - An arm of the Rural Utilities Service that provides supplemental financing for rural telephone systems.
Rural Telephone Cooperative (RTC) - One of the individual, consumer-owned businesses first organized in the 1890s to bring telephone service to rural farms and homes. As with other cooperative businesses, any profit, or margin, is returned to the consumers according to the amount of business conducted with the cooperative.
Rural Telephone Finance Cooperative (RTFC) - Lends money to rural telephone and telecommunication systems.
Rural TV - Package of satellite television programming offered to rural people through the National Rural Telecommunications Cooperative.
Rural Utilities Service (RUS) - The federal agency that deals generally with electric membership corporations (rural electric cooperatives). Among other functions, the RUS approves and guarantees loans to electric cooperatives for generation, transmission, and distribution facilities. Formerly known as Rural Electrification Administration (REA) 1935-1994.
SSag - The distance between the actual location of a conductor (at its lowest point in a given span) and an imaginary line drawn between the conductors two adjacent supports. See also voltage sags.
Satellite dish - A large, bowl-shaped antenna used to receive broadcasts transmitted from orbiting satellites.
Scheduled outage - The shutdown of a generating unit, transmission line, or other facility, for inspection or maintenance, in accordance with an advance schedule.
Scrubbers - Used to clean pollutants from stack gases at power plants that burn fossil fuel.
Seasonal consumer - Any consumer who uses electricity for a fractional part of the year.
Seasonal Energy Efficient Ratio (SEER) - A standard method of rating air conditioners based on three tests. All three tests are run at 80 degrees (F) inside and 82 degrees (F) outside. The first test is run with humid indoor conditions, the second with dry indoor conditions, and the third with dry conditions cycling the air conditioner on for 6 minutes and off for 24 minutes. The published SEER may not represent the actual seasonal energy efficiency of an air conditioner in your climate because it is calculated using an average U.S. climate.
Seasonal Performance Factor (SPF) - The ratio of seasonal kilowatt-hour used by heat pumps vs. the seasonal kilowatt-hour used by resistance electric heat for the same space under the same conditions.
Seasonal rates - Rate schedules that are structured and billed on a seasonal basis.
Self-generation - The capability of providing your own electricity through some means other than a utility, such as a wind generator, diesel or gas generator or heat recovery from an industrial manufacturing process.
Sensible cooling load - The heat gain of a home due to conduction, solar radiation, infiltration, appliances, people and pets. Burning a light bulb, for example, adds only sensible load to the house. The sensible load raises the dry-bulb temperature.
Service - The conductors and equipment used to deliver energy from the distribution transformer or secondary lines to the end users (customers).
Service area - Territory in which a utility system is required or has the right to supply or make electric service available to consumers.
Service charge - An amount on a consumer’s electric bill designed to recover some of the fixed costs of providing electric service; generally a flat rate charged whether or not any electricity is consumed.
Short circuit - Establishment of an accidental or unintended electrical conducting path that bypasses the planned route from the electrical power source to the intended load (end user).
Short hedge - One of the most common commercial applications of futures which relates to protection from exposure to falling cash market prices.
Short-term debt - Notes, drafts or other similar evidences of indebtedness payable on demand or which, by their terms, are payable within one year from the date of issuance.
Short ton - A unit of weight equal to 2,000 pounds.
Single-phase kvA - Volts x amperes, 1000
Singe-phase power - An electric circuit that consists of one alternating current, typically used for all household power.
Single-phase service - Energy supply usually consisting of two wires or conductors energized at 120V (240V line-to-line) and one grounded neutral conductor. Can be either overhead or underground.
Single-phase system - Current flows from the phase conductor through the electrical load to the neutral conductor and returns to the source.
Single pole - Transmission lines are constructed either of aluminum or copper wires. These wires are carried on either a steel tower or wood pole structures. One of these wood transmission poles is referred to as a single pole structure.
Small-power producer - Generates electricity from facilities much smaller than those of base-load power plants; uses biomass, solid waste, geothermal energy or renewable resources as its primary energy source.
Solar power - Energy from the sun's radiation converted into heat or electricity. (See active solar energy, passive solar energy)
Sound Rating (SR) - A tone corrected A-weighted sound power level expressed in bels. The Sound Rating is based on tests performed at Standing Rating Conditions (cooling).
Spike - An increase in voltage lasting less than 1/60th of a second. Usually caused by switching of heavy loads.
Spinning reserve - Generating units connected to the bus and ready to take load.
Spot purchases - A single shipment of fuel or volumes of fuel, purchased for delivery within one year. Spot purchases are often made by a user to fulfill a certain portion of energy requirements, to meet unanticipated energy needs, or to take advantage of low-fuel prices.
Stability - The property of a system or element by virtue of which its output will ultimately attain a steady state. The amount of power that can be transferred from one machine to another following a disturbance. The stability of a power system is its ability to develop restoring forces equal to or greater than the disturbing forces so as to maintain a state of equilibrium.
Stack scrubber - An air pollution control device that usually uses a liquid spray to remove pollutants, such as sulfur dioxide or particulates, from a gas stream. Method used is either absorption or chemical reaction. Scrubbers are also used to reduce the temperature of the emissions.
Stakeholder - A stakeholder is any individual or party with a vested interest in the outcome of a debate. Generally, a stakeholder will somehow be impacted by this outcome.
Standby facility - A facility that supports a utility system and is generally running under no-load. It is available to replace or supplement a facility normally in service.
Standby service - Support service that is available, as needed, to supplement a consumer, a utility system, or to another utility if a schedule or an agreement authorizes the transaction. The service is not regularly used.
Static electricity - Electric discharge resulting from an accumulation of electric charge on an insulated body.
Steam generating station - A conventional generating station where the generator is driven by steam. The steam is generated by the heat produced from the burning fossil fuels.
Step rate - A charge for electricity that depends on the total amount of kilowatt-hours used; the more a consumer uses, the cheaper the cost of each kilowatt-hour.
Stranded benefits - Public interest programs and goals that could be compromised or abandoned by a restructured electric industry. These potential “stranded benefits” might include environmental protection, fuel diversity, energy efficiency, low-income rate payer assistance, and other types of socially beneficial programs.
Stranded costs - Costs incurred or investments made by an electric utility to ensure reliable electric service for the future, that with deregulation may not be recoverable in a competitive marketplace.
Stranded investment - Transmission and/or generation investments not being used and not generating revenue because of open transmission access, but are still being paid for by the original investor.
Stray voltage - Neutral to earth voltage, which is voltage that exists between the system neutral (grounded conductor) and the earth.
Strip mining - Producing coal from underground by digging pits with giant shovels called draglines.
Sub-bituminous coal - Coal with medium capability of producing heat. (See anthracite, bituminous coal, lignite)
Submetering - The practice of metering energy beyond the customer’s utility meter, generally for distribution to building tenants.
Subsidiary - A business controlled by another company, called the parent company, but with its own business identity, including charter, officers and board of directors.
Substation - An electrical facility containing equipment for controlling the flow of electricity from supplier to user. Usually a fenced area containing transformers, voltage regulators, switching, devices, and metering equipment.
Substation Control and Data Acquisition - A system that monitors activity at an electric system’s substation and transmits the information to a central computer.
Sulfates - A class of secondary pollutants that includes acid sulfates and neutral metallic sulfates.
Sulfur - An element that appears in many fossil fuels. In combustion of the fuel, the sulfur combines with oxygen to form sulfur dioxide.
Sulfur dioxide - One of several forms of sulfur in the air, sulfur dioxide is an air pollutant generated principally from combustion of fuels that contain sulfur (i.e. coal and other fossil fuels).
Summer peak - The greatest load on an electric system during a specified demand interval in the summer season, usually between June 1 and September 30.
Superconducting supercollider - A proposed energy producing system in which protons guided at extremely high speeds by superconducting magnets collide inside an underground loop.
Superconductivity - The ability to carry electric current without loss to resistance.
Superconductors - Materials that permit an unimpeded flow of electricity.
Supervisory Control and Data Acquisition (SCADA) - A remote system to collect information from a substation or generating plant along with some remote control.
Supply options - Deals with measures affecting the source and cost of power and energy requirements. Most supply measures are coordinated by the G&T. For example, the G&T may produce its own power, purchase firm power from an IOU, acquire power from a government hydroelectric facility, and make purchases from an industrial cogenerator. Of course, making purchases at the most opportune time and taking advantage of discounts can result in savings to the member consumers.
Surge - Overvoltages lasting longer than 1/60th of a second. Can be caused by the automatic switching on or off of motor driven devices, a lightning strike on or near a power line, or even something as simple as the discharge of static electricity build up on a copier from the shuffling of paper.
Surge suppressor - A device used to reduce damage caused by transient voltage surges (spikes).
Surplus sales - The sale of energy generated that is beyond the needs of the producing system. Volume of these sales is dependent on the need of other interconnected utilities and the competitive pricing in power marketing.
Synthetic fuel (Synfuel) - A source of energy created by changing the molecular structure of a hard-to-use fuel to a more usable state. Fuel produced artificially from hydrocarbons, peat or carbohydrates, such as coal converted to synthetic oil or gas.
Synthetic gas (Syngas) - The name given to a gas mixture that contains varying amounts of carbon monoxide and hydrogen generated by the gasification of a carbon containing fuel to a gaseous product with a heating value.
System demand - The total amount of energy required to supply all consumers.
System peak - Used to indicate the maximum load on a system during any particular period. For example, if the maximum demand on the system is 600,000 kilowatts for a particular month, there is said to be system peak of 600,000 kilowatts.
Systemwide power agreement - A common agreement between a power supply system and all its members whereby the power supply system agrees to provide wholesale power to its members, and the members agree to purchase this power under terms and conditions set out in the agreement.
TTake-and-pay - A power sales contract that stipulates payment will be made only for power actually delivered.
Take-or-pay - A power sales contract that stipulates payment must be made whether or not the power contracted for is received. Such an arrangement is required, for example, in ratchet contracts and for projects that are financed by the issuance of electric revenue bonds (bonds that will be repaid from electric revenues only).
Takeover - The acquisition of a cooperative or company, accomplished by buying the owners’ equity.
Tap - An electric circuit with limited capacity extending from a distribution line; usually supplies a small number of customers.
Tariff - An explanation of a utility’s rates, as filed with the commission that regulates that utility (e.g. the Minnesota Public Utilities Commission).
Tennessee Valley Authority (TVA) - Generation and transmission company supplying power to 160 electric utilities in a seven-state region including Tennessee.
Territorial integrity - Legally supported right of an electric power supplier not to have its territory or consumers taken over by another power supplier.
Therm - A unit of heat equal to 100,000 Btus.
Thermal conductivity values –
U Factor: the rate of heat flow through one square foot of completed structural sections, such as wall, glass, ceiling, etc. in one hour with a temperature difference of one degree between the inside and outside surfaces. To convert to watts/sq. ft.: W=U Factor times temp. divided by 3.413.
K Factor: the rate of heat flow in Btuh through one square foot of building material, one-inch thick, in one hour with temperature difference of one degree between the two surfaces.
C Factor: the definition is the same as the K Factor except that C Factors are used for materials other than those that are one-inch thick, such as one-half inch sheet rock or eight-inch concrete block.
R Factor: the rate at which insulation, building material, or a building structure resists the passage of heat in any direction. The U, K, and C Factors should be kept as low as possible, and the R Factor as high as possible.
Thermal generation - Producing electric power by utilizing the energy in heat to generate electricity.
Third-party suppliers - The generic term for non-utility entities seeking to sell power.
Three-phase kvA - Volts x amperes x 1.73/1000
Three-phase power - An electric circuit that consists of three separate currents delivered at one-third cycle intervals by means of a three-wire or four-wire circuit; typically utilized by commercial and industrial loads.
Three-phase service - Generally has four wires from the power pole to the meter - three “hot” wires and a neutral wire. Even if a three-phase power line is available to a consumer, it does not necessarily mean that the consumer has three-phase service. Single-phase service is often supplied from three-phase lines.
Three-phase system - A combination of circuits that differ in phase by one-third of a cycle (120 electrical degrees).
Time-of-day rates - Rates that differentiate charges for energy used during more expensive peak (usually daytime) periods and less expensive off-peak (usually nighttime) periods. The system would require installation of meters, which separately register usage during high-peak and low-peak periods. The goal is to reduce peak load, thus curbing the need to build additional power plants.
Time-of-use metering - A metering system that measures a customer’s power usage at various intervals during each 24-hour period. A utility can determine which of its customers are using the most power at the time of the system’s maximum demand and are thereby making the heaviest contributions to the system’s peak.
Time-of-use rates - A generic term used to describe any rate whose applicability depends on the time of use. Rates such as off-peak, interruptible, or time-of-day, are all time-of-use rates.
Times interest earned ratio (TIER) - The ratio of margins to long-term interest expense. (A cooperative with interest costs of $100,000 and margins of $150,000 has a TIER of 2.5.) This ratio is of vital interest to lenders, since it is an indication of the ability of the cooperative to meet its financial obligations.
Tipple - A facility that crushes coal and loads it onto trucks or rail cars.
Touchstone Energy -The brand identity of a nationwide alliance of local, consumer-owned utilities providing high standards of service to the customer, big and small, and the communities they serve.
Transformer - A device used to raise or lower voltage. Transformers are used to increase voltage at the generating plant for transmission to the substation. The substation transformers reduce voltage to distribution level: a distribution transformer reduces the voltage to a utilization level; another transformer may be required to further reduce the voltage for a doorbell.
Transmission - The process of transporting electric energy over long distances to other principal parts of an electric system or to other utility systems for subsequent voltage reduction and distribution.
Transmission grid - An interconnected system of wires and other equipment used to move large amounts of electricity from the generation source to a distribution system.
Transmission line - Poles, towers, structures and conductors used to transmit power from one terminal or station to another.
Transmission system - That system formed by the operation and possible interconnection of multiple transmission lines.
Turbine - In the generation of electricity, steam is directed under high pressure onto the blades of the turbine. The pressure makes the turbine, and the attached generator, spin to generate electricity.
UUL - Registered trademark of the Underwriters' Laboratory.
URD - Underground Residential Distribution
Unbundling - The separation of generation, transmission, and distribution services. Conceivably an end-user could buy generation from one place, transmission from another and distribution from still another.
Undue discrimination - Discrimination results when a cooperative provides service at rates that are not proportional to costs. Undue discrimination cannot be justified, does not promote economic efficiency, and communicates improper price signals.
Uniform system of accounts - Prescribed financial rules and regulations established by the Federal Energy Regulatory Commission (FERC) for utilities subject to its jurisdiction under the authority granted by the Federal Power Act.
Universal service - The belief that electric service must be available in a nondiscriminatory manner to all those who request it.
Uranium - A soft, radioactive metal and the heaviest of natural elements, it is a fuel of nuclear energy. A pound of enriched uranium contains nearly 3 million times the energy contained in a pound of coal.
Used and useful - Requirement that before the fixed assets of a plant may be included in a utility’s rate base, the plant in question must be in operation (used) and be needed to provide service to the public (useful).
Utility - A company that provides electricity, water, gas, phone or Internet for residential and commercial use. May or may not be a cooperative entity.
Utility plant - The fixed assets of a utility.
VVertical integration - Having control and input during the full cycle of a good or service, from production through delivery. Vertically integrated utilities generate, transmit and deliver electric power and services.
Volt (V) - A unit of electric force that measures the pressure of electricity. For example, 1 volt will cause 1 ampere of electricity to flow through 1 ohm of resistance. In the United States, the two standard residential voltages are 120 volts and 240 volts.
Volt-ampere (VA) - The apparent power consumed by a device. This is the product of the measured current and the measured voltage delivered to an appliance.
Voltage - The “pressure” that causes electrons to flow. Voltage is a measure of the potential for current flow and may exist between objects without a flow of current.
Voltage reduction - Any intentional reduction of system voltage by 3 percent or greater for reasons of maintaining the continuity of service of the bulk electric power supply system.
Voltage sag - Under-voltage conditions of 1/60th of a second to 1/10th of a second duration. Caused by improper grounding, undersized wiring or sudden start-ups of large electrical loads. Also called voltage dips.
WWatt (W) - The standard unit of electric power in the United States. Electrical power measured in watts is equal to the voltage (V) times the current (I). W=V x I.
Watt-hour (WH) - A unit of electrical energy equal to one watt of power acting for one hour.
Watt-hour Meter - Instrument used to measure and record watt-hour consumption.
Wet-bulb temperature - When a wet wick is placed over a standard thermometer and air is blown across the surface, the water evaporates and cools the thermometer below the dry-bulb temperature. This cooler temperature, the wet-bulb temperature, depends upon how much moisture there is in the air.
Wheeling - The use of a utility's transmission lines by other power producers.
Wheeling charge - An amount charged to an electric system by another for the transmission of energy to and from another system.
Wholesale customer - A power purchaser that buys for resale to retail customers.
Wholesale power customer - A power purchaser that buys bulk power for resale to retail customers.
Wholesale wheeling - The use of a utility’s transmission and distribution system to move power to another utility or wholesale customer.
Willie Wirehand - A cartoon figure created in 1950 by free-lance artist Drew McLay and adopted as NRECA’s mascot in 1951.
Winter peak - The greatest load on an electric system during a specified demand interval in the winter season, usually between December 1 of a calendar year and March 31 of the next calendar year.
Working capital - The amount of cash or other liquid assets that a company must have on hand to meet the current cost of operations until it is reimbursed by its customers.
XYZYouth Leadership Council (YLC) - Composed of one member from each state that participates in the annual Rural Electric Youth Tour.
Glossary of Terms courtesy of the Minnesota Rural Electric Association.
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