• Billing Demand

    The demand charge that a customer actually pays for the reservation of capacity or facilities used, regardless of consumption. Billing demand may be based on a contract maximum, a contract minimum, or a previous peak or maximum demand and, therefore, may not necessarily coincide with the actual measured demand for the billing period. Also referred to as Ratchet, or Ratcheted Demand Charge.

  • Biomass Conversion

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

  • Bituminous Coal

    Older geologic age than subbituminous coal, with higher heating value, lower sulfur, typically higher volatile matter and ash than subbituminous coal. Used for both steam and electricity production, as well as for production of steel. Metallurgical coal is typically bituminous coal, with a free swelling index of over 4.5 and with "dial divisions per minute" (a measure of "fluidity") of over 1,500 and sometimes over 20,000. Heating value of bituminous coal typically ranges from 10,000 to 13,000 Btu/lb.

  • Black Start

    A rapid start up of an off line, idle, non-spinning electric generation source. Equivalent to the starting up of a car after it has not been used for a while.

  • Blackout

    The emergency loss of the source of electricity serving an area caused by failure of the generation, transmission, or distribution system.

  • Blanket Certificate (Authority)

    General authorization granted by the FERC under NGA section 7 (c) for the recipient to engage in a FERC jurisdictional activity, such as transportation or sales of natural gas, on behalf of a general class of potential customers, without individual case-by-case review and approval.

  • Blanket Sales Certificate

    The authorization granted to pipelines and/or their marketing affiliates, as well as other sellers, to sell natural gas for resale at market-based prices.

  • Blowdown

    Releasing of pressure by rapid venting in a tank, pipeline, or refinery unit.

  • 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 electrical combustion source is transmitted to a fluid contained within the tubes in the boiler shell. This fluid is delivered to an end-user at a desired pressure, temperature, and quality. Boilers are often classified as steam or hot water, low pressure or high pressure, capable of burning one fuel or a number of fuels.

  • Boiler Fuel

    Fuels suitable for generating steam or hot water in large industrial or electrical generating utility applications.

  • Boiler Fuel Gas

    Natural gas used as fuel for the generation of steam or hot water.

  • Book Cost

    The amount at which property or assets are recorded in a company's accounts without deducting depreciation, amortization, or various other items.

  • Book Transfer

    Transfer of title without a physical movement.

  • Bottleneck Facility

    A point on the system, such as a transmission line, through which all electricity must pass to get to its intended buyers. If there is limited capacity at this point, some priorities must be developed to decide whose power gets through. It also must be decided if the owner of the bottleneck may, or must, build additional facilities to relieve the constraint.

  • BPA

    Bonneville Power Administration. A power marketing and electric transmission agency of the United States government with headquarters in Portland, Oregon.

  • British Thermal Unit (BTU)

    The amount of heat energy necessary to raise the temperature of one pound of water one degree Fahrenheit.

  • British Thermal Unit (Btu), Dry

    A measure of the heating value of natural gas that is free of moisture, or contains less that 7 pounds per Mcf of water vapor. Condition under which natural gas is usually delivered for first sales.

  • British Thermal Unit (Btu), Saturated

    A measure of the heating value of natural gas that is fully saturated with water vapor under standard temperature, pressure and gravity conditions. This standard of measure usually has little or nothing to do with the state in which the natural gas is actually delivered for first sales.

  • Broker

    A third party that earns a profit by establishing a transaction between a willing Seller and Purchaser without ever taking ownership.

  • Brownout

    The partial reduction of electrical voltages caused by customer demand being higher than anticipated or by the failure of the generation, transmission, or distribution system. A brownout results in lights dimming and motor-driven devices slowing down.

  • Bubble Point

    The temperature and pressure at which a liquid begins to convert to a gas.

  • Bulge

    A rapid increase in futures prices.

  • Bulk Electric System

    The aggregate of electric generating plants, transmission lines, and related equipment. The term may refer to those facilities within one electric utility or within a group of utilities in which the transmission lines are interconnected.

  • Bulk Power System

    A term describing all electric generating plants, transmission lines, and equipment. See Bulk Electric System.

  • Bundled Sales Service

    The sale and/or transportation of natural gas or electricity under one rate, which does not differentiate separate rate components for the sale, transportation, storage or gathering services associated with such sale or transportation.

  • Burner Capacity (Burner Rating)

    The maximum Btu per hour that can be released by a burner while burning with a stable flame and satisfactory combustion.

  • Burner Tip

    The end of the transportation of natural gas from the wellhead, and the point of consumption.

  • Busbar

    The point at which power is available for transmission. A conductor, or group of conductors, that serve as a common connection for two or more circuits, generally in the form of insulated cable, rigid rectangular or round bars, or stranded overhead cables held under tension. The equivalent, in electric power terms, of the gas plant tailgate.

  • Busbar Cost

    The cost of producing one kWh of electricity delivered to, but not through, the transmission system.

  • Butane (C4H10)

    A hydrocarbon substance consisting of molecules composed of four atoms of carbon and ten atoms of hydrogen, used primarily for blending in high-octane gasoline, for residential and commercial heating, and in manufacture of chemicals and synthetic rubber.

  • Butylene (C4H8)

    A hydrocarbon substance consisting of molecules composed of four atoms of carbon and eight atoms of hydrogen, used primarily for blending in high-octane gasoline, for residential and commercial heating, and in manufacture of chemicals and synthetic rubber.

  • Buy/Sell

    An arrangement whereby a party sells gas at the wellhead to a party with priority space in the pipeline queue, and then repurchases the gas downstream, paying transmission costs and any prearranged differentials.

  • Buy Through

    An agreement between utility and customer to import power when the customer's service would otherwise be interrupted.

  • Buyout

    A swap is closed and settled at current price.

  • Bypass

    The action of a retail customer to obtain power or natural gas directly from a wholesale supplier or transporter, thus eliminating any utility charges applicable to distribution. This term is also sometimes applied when an end-user closes down operations, installs alternate fuel capability, or moves its operations to the service area of another natural gas supplier, thereby curtailing its purchases from its traditional supplier.

  • CAAA90

    The Clean Air Act Amendments of 1990.

  • Call Option

    The right, but not the obligation to buy the underlying assets at an agreed upon price (strike or exercise price) during the option term. It gives the holder or buyer of the option the right to buy the underlying instrument at an agreed strike price in the future when prices may be higher than the strike price. Selling a call option obligates the seller to sell the underlying instrument at an agreed strike price in the future when prices may be higher than the strike price. A call is the opposite of a put.

  • Callable Swap

    A swap in which the fixed-rate receiver has the right to terminate the swap after a certain time if rates rise. Also known as a cancelable swap.

  • Calorific Value


  • Calorimeter

    An apparatus for measuring the amount of heat released by the combustion of a compound or mixture.

  • Cap

    A call option on forward interest rates. A cap gets more expensive as the yield curve steepens and as the volatility of the underlying interest rate increases.

  • Capability

    The ability of a transmission interface between two control areas to carry real power flows, typically measured in megawatts. 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.

  • Capacitor

    A transmission element designed to inject reactive power into the transmission network. Also utilized to increase voltages, reduce loadings, and increase available kW output from generators. Capacitor ratings typically given in Megavars.

  • Capacity Brokering

    The assignment of rights to receive firm gas transportation service.

  • Capacity Charge

    One element of a two-part pricing method used in power transactions (energy charge is the other element). The Capacity Charge, sometimes called Demand Charge, is assessed on the amount of capacity being purchased or demanded. The Capacity Charge is typically expressed in $/kWmonth (kilowatt-month).

  • Capacity (Electric)

    The real power output rating of a generator or system, typically in megawatts, measured on an instantaneous basis. The amount of electric power delivered or required for which a generator, turbine, transformer, transmission circuit, station, or system is rated by the manufacturer. The maximum power that can be produced by a generating resource at specified times under specified conditions.

  • Capacity Emergency

    A condition that exists when a system's or pool's load exceeds its operating capacity and cycling reserve margin, plus firm purchases from other systems and available import from adjacent systems.

  • Capacity Factor

    Ratio of average generation to the capacity rating of an electric generating unit for a specific period (expressed in percentage).

  • Capacity (Gas)

    The maximum amount of natural gas that can be produced, transported, stored, distributed, or utilized in a given period of time under design conditions.

  • Capacity Margin

    The amount of capacity above planned peak system demand available to provide for scheduled maintenance, emergency outages, system operating requirements, and unforeseen electricity demand.

  • Capacity, Peaking

    The capacity of facilities or equipment normally used to supply incremental gas or electricity under extreme demand conditions. Peaking capacity is generally available for a limited number of days at a maximum rate.

  • Capacity, Pipeline

    The maximum throughput of natural gas over a specified period of time for which a pipeline system or portion thereof is designed or constructed, not limited by existing service conditions.

  • Capacity, Purchased

    The amount of capacity available for purchase from other power systems. Usually measured in megawatts (MW).

  • Capacity Release

    The assignment, allocation, or release of firm gas transportation rights to another party authorized under Order No. 636, done on a permanent or temporary basis, and awarded to the highest bidder.

  • Capital Efficiency

    Measures of the return on capital we have expended or invested and is commonly measured by ROCE (Return on Capital Employed) or ROIC (Return on Invested Capital).

  • Capital Velocity

    The rate at which capital is recycled to leverage the assets and skills of the enterprise more quickly without the need for a larger capital base.

  • Captive (Core) Customer

    Buyer that can purchase natural gas from only one supplier, with no access to alternate fuel sources, usually describing a residential or small commercial user, but may apply to a large industrial and electric utility user as well.

  • Captive Mine

    A coal mine that is typically contiguous to a power plant, which is owned or controlled by the operator of the power plant, and which supplies most of its coal to the power plant.

  • Carbon Black

    Almost pure amorphous carbon consisting of extremely fine particles, usually produced from gaseous or liquid hydrocarbons by controlled combustion with a restricted air supply or by thermal decomposition.

  • Carbon Dioxide (C02)

    A gaseous substance at standard conditions composed of one carbon atom and two oxygen atoms, produced when fossil fuels are burned, and is thought to be a major contributor to the "greenhouse effect." Combustion of natural gas emits only about 50% as much carbon dioxide as combustion of coal.

  • Carriage

    The transportation of a third party's natural gas by a pipeline as a separate service for a fee, as contrasted with the pipeline's transportation of its own system supply natural gas.

  • Carrying Charge

    The costs of storing a physical commodity, including storage costs, insurance, interest and/or opportunity costs.

  • Cascading Outage

    Successive system loss (uncontrolled), resulting from an on-site incident. Results in a widespread system collapse.

  • Cash-Out

    Procedure in which shippers are allowed to resolve imbalances by cash payments, in contrast to making up imbalances with gas volumes in-kind.

  • Casinghead Gas

    See GAS.

  • Ceiling Price

    The maximum lawful price that could be charged for the first sale of a specified NGP A category of natural gas, pre-1993.

  • Certificate of Public Convenience and Necessity

    Authorization to sell for resale or to transport natural gas in interstate commerce; or to construct, or acquire and operate, any facilities necessary therefore, subject to FERC jurisdiction under Section 7 of the NGA. May also refer to a similar permit issued by a state commission to a gas utility.

  • Check Meter

    See METER, GAS.

  • Circuit

    A conductor or a system of conductors through which electric current flows.

  • City Gate (City Gate Station, Town Border Station)

    Location at which natural gas ownership passes from one party to another, neither of which is the ultimate consumer; the point at which interstate and intrastate pipelines sell and deliver natural gas to local distribution companies.

  • City Gate Rate (Gate Rate)

    The rate charged a distribution utility by its suppliers. It refers to the cost of the natural gas at the point at which the distribution utility historically took title to the natural gas.

  • Class of Service

    A group of customers with similar characteristics (e.g., residential, commercial, industrial, etc.) that are identified for the purpose of setting a rate for service.

  • Clean Coal Technologies

    Processes designed to burn coal with little or low emissions, including coal with either high sulfur content or high ash content that might make it unattractive as a fuel.

  • Coal

    A black or brownish-black solid combustible substance formed by the partial decomposition of vegetable matter without access to air.

  • Coal Ash

    Impurities consisting of silica, iron, alumina, and other noncombustible matter that are contained in coal. Ash increases the weight of coal, adds to the cost of handling, and can affect its burning characteristics. Ash content is measured as a percent by weight of coal on an "as received" or a "dry" (moisture-free, usually part of a laboratory analysis) basis.

  • Coal Bed Gas, Coal Gas

    See GAS.

  • Coal Classifications

    Short hand references to various types of coal, generally making reference to the age of the coal, its relative moisture content, heating value and hardness.

  • Coal Gasification

    A controlled process of reacting coal, steam, and oxygen under pressure and elevated temperature to produce coal gas. The gas created has a low heating value, but catalytic upgrading can be employed to produce high Btu pipeline-grade gas.

  • Coal Resources

    The sum of all coal deposits, identified and undiscovered.

  • Coal Seam

    A lens or layer of coal, which is a naturally occurring, rock like, black to brown derivative of forest type vegetation, which has been compressed over time and typically subjected to heat, and which contains sufficiently low incombustible materials so that it provides a competent fuel.

  • Coal Tar Product

    A black, sticky liquid, thicker than water, produced during the process of carbonizing coal in coke ovens.

  • Cogeneration

    (1) Any of several processes which either use waste heat produced by electricity generating to satisfy thermal needs or process waste heat to electricity or produce mechanical energy. (2) The use of a single prime fuel source in a reciprocating engine or gas turbine to generate both electrical and thermal energy to optimize fuel efficiency. The dominant demand for energy may be either electrical or thermal. Usually it is thermal with excess electrical energy, if any, being transmitted into the local power supply companies' lines.

  • Cogenerator

    An entity owning a generation facility that produces electricity and another form of useful thermal energy (such as heat or steam), used for industrial, commercial, heating, or cooling purposes.

  • Coincidence Factor

    The ratio of the maximum demand of a group, class, or system as a whole to the sum of the individual maximum demands of the several components of the group, class or system. Reciprocal of the Diversity Factor.

  • Coincident Demand

    The sum of two or more demands that occur in the same time interval.

  • Coincidental Peak Load

    The sum of two or more peak loads that occur in the same time interval.

  • Coke

    A hard, dry carbon substance produced by heating coal to a very high temperature without air. Coke is used in the process of making iron and steel. (See also PETROLEUM COKE)

  • Collar

    A hedging strategy. Simultaneously buying a cap and selling a floor. Collars effectively lock in a rate for borrowing costs: The cap sets a maximum possible borrowing rate for the life of a contract, while the floor establishes a minimum rate for borrowing costs. Also referred to as a Fence or Min-Max.

  • Combination Utility

    A utility supplier of both natural gas and some other utility service (electricity, water, transit, etc.).

  • Combined Billing


  • Combined Cycle

    The combination of one or more gas turbine and steam turbines in an electric generation plant. 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).

  • Combustion Turbine (CT)

    A fuel-fired turbine engine used to drive an electric generator. Combustion turbines, because of their generally rapid firing time, are used to meet short-term peak demands placed on power systems.

  • Commercial

    A sector of customers or service defined as non-manufacturing business establishments, including hotels, motels, restaurants, wholesale businesses, retail stores, and health, social, and educational institutions. A utility may classify the commercial sector 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.

  • Commercial Operation

    An operating condition that begins when control of the loading of a generator is turned over to the system dispatcher.

  • Commercial Operation Date (COD)

    The date at which a utility facility is declared in service and after which the accumulation of AFUDC ceases.

  • Commission

    (1) In the context of futures trading, the fee charged by a futures broker for executing an order. (2) The Federal Energy Regulatory Commission (3) State Public Utility's Commission(s).

  • Commitment or Open Interest

    The number of contracts at a given point in time for which there is no offsetting sale or purchaser or actual contract delivery.

  • Committed Gas


  • Commodity Charge (or Rate)

    A charge per unit of service actually delivered to the buyer. Compare DEMAND CHARGE.