• 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.

  • Commodity Costs

    Those costs that are allocated on the basis of actual use of service.

  • Commodity Price Adjustment Clause

    A provision in a rate schedule for an adjustment of a customer's bill if the price of commodities or index of commodity prices varies from a specified standard.

  • Common Carrier

    A facility obligated by law to provide service to all potential users without discrimination, with services to be prorated among users in the event capacity is not sufficient to meet all requests. Interstate oil pipelines are common carriers, but interstate natural gas pipelines are not.

  • Commonly or Jointly Owned Units

    These terms may be used interchangeably to refer to a unit in which two or more entities share ownership.

  • Comparability of Service

    Equal access to all natural gas pipeline transportation services, including storage and gathering, regardless of whether the customer purchases gas from the pipeline or from a third party. FERC Order No. 636 redefined comparability to require equality of service.

  • Compound derivative

    Two examples of compound derivatives are:

  • Compressed Natural Gas

    See Gas.

  • Compression

    The action on a material which decreases its volume as the pressure to which it is subjected increases. Natural gas is usually compressed for transport.

  • Compression Ratio

    The relationship of absolute outlet pressure at a compressor to absolute inlet pressure.

  • Compressor

    A mechanical device for increasing the pressure of a gas.

  • Compressor Fuel

    Natural gas burned as fuel to operate a compressor.

  • Compressor Station

    Facility that provides energy to move natural gas within a pipeline by increasing the pressure of the gas at the discharge side of the facility compared to the intake side.

  • Condensate

    The liquid resulting when a vapor is subjected to cooling and/or pressure reduction.

  • Condensate, Natural Gas

    Hydrocarbons, existing as vapor in natural gas reservoirs, that condense to liquids as their temperature and pressure decrease when natural gas is produced. Natural gas condensates consist mostly of pentanes (C5H12) and some heavier hydrocarbons. Once condensed, natural gas liquids are usually blended with crude oil for refining. Compare LIQUIDS, NATURAL GAS.

  • Conductivity

    A measure of a material's ability to conduct/transmit an electric charge.

  • Conductor

    A substance or body, usually in the form of a wire, cable, or busbar, that allows a current of electricity to pass continuously along it.

  • Confirmed Nominations

    Pipeline verification that a change in a customer's level of transportation service will be matched by a change in supplier quantities.

  • Congestion Costs

    Costs that arise from the redispatch of a system due to transmission constraints.

  • Conjunctive Billing

    The process of billing for several natural gas demands, services, or meters as if the billing were for a single demand, service, or meter. Conjunctive billing is sometimes referred to as Combined Billing.

  • Connection

    The physical junction (e.g., transmission lines, transformers, switch gear, etc.) between two electric systems permitting the transfer of electric energy.

  • Conservation

    Demand-Side Management (DSM) strategy for reducing generation capacity requirements by implementing programs to encourage customers to reduce their load during many hours of the year. Examples include utility rebate and shared savings activities for the installation of energy efficient appliances, lighting and electrical machinery, and weatherization materials. A resource produced by increasing the efficiency of energy use, production, or distribution.

  • Constraint

    A generator's high or low output limit, line rating, or other limiting condition on the electrical system.

  • Construction Expenditures

    Cost of construction for additions to, renewals of, and replacements of plant facilities, including overhead and allowance for funds used during construction. Excludes the purchase cost of an acquired operating unit or system of utility plant, accounting transfers and adjustments to utility plant, and cost to remove plant facilities from service. Construction expenditures are capitalized in a utility's rate base.

  • Construction Work In Progress (CWIP)

    The account that includes the total of the balances of work orders for work in process of construction. This line item mayor may not be included in the utility's rate base.

  • Consumer

    The ultimate user of natural gas, as contrasted to a "customer" who may purchase natural gas for resale.

  • Consumption (Fuel)

    The amount of fuel used for gross generation, providing standby service, start-up and/or flame stabilization.

  • Contained Helium

    See HELIUM.

  • Contango Market

    A term used in futures trading meaning that prices are progressively higher in succeeding delivery months than in the nearest delivery month.

  • Contingency

    A possible event for which preparations are made. Typically the loss of generating capacity or a transmission element.

  • Contingency Reserve

    An additional amount of operating reserve sufficient to reduce area control error to zero in 10 minutes following loss of generating capacity, which would result from the most severe single contingency.

  • Continuous Miner

    A cutting head mining machine typically using bits mounted onto a rotating drum to cut coal from a coal seam and direct it toward a coal car (wheeled or track conveyance) or conveyor belt to move the coal from the face without interrupting the work of the miner operating the machine except for the occasional insertion of roof bolts above the miner for roof control.

  • Contract Adjustment

    Under Order No. 636, the ability of customers to reduce, in whole or in part, their firm purchase and/or transportation obligations under contracts with their pipeline suppliers. Firm transportation, in contrast to firm sales, cannot be reduced unless the pipeline agrees or an alternative purchaser is found at the maximum price.

  • Contract Carrier

    A facility that voluntarily provides its services to others on a private contractual basis.

  • Contract Conversion

    Under FERC Orders No. 500 and 636, the option of pipeline firm sales customers to convert their sales service entitlement to firm transportation service entitlement.

  • Contract Demand

    The amount of service a seller agrees to provide on a periodic (daily, monthly, annually) basis. Contract demand is a maximum amount.