• Abandoned Well

    An oil or gas well not in use because it was a dry hole originally, or because it has ceased to produce in paying quantities. State statutes and regulations require the plugging of abandoned wells to prevent oil, gas, or water seeping from one stratum of underlying rock to another.

  • Abandonment

    Termination of a sale or interstate transportation of natural gas. Abandonment of a service that is subject to FERC jurisdiction requires some type of advance determination by the FERC under Section 7 (b) of the NGA that the "present or future public convenience and necessity" requires termination.

  • Abandonment, Pregranted

    A provision of a FERC certificate of public convenience and necessity that authorizes abandonment on a future condition subsequent or on a date certain.

  • Absolute Pressure


  • Access

    The legal right to use an electrical or gas transmission and /or distribution system as a means of transferring electrical energy or natural gas as set forth in the contract.

  • Access Charge

    A charge levied on power supplied, 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.

  • Account No. 191

    Tracking system established by the FERC for unrecovered gas supply costs incurred by interstate pipelines, to be eliminated once pipelines sell gas at market-based rates under blanket sales certificates pursuant to Order No. 636.

  • Account No. 858

    Tracking system established by the FERC used by interstate pipelines for costs incurred transporting sales gas on upstream pipelines.

  • Ace

    See Area Control Error.

  • Acid Rain

    Also called acid precipitation or acid deposition, acid rain is precipitation containing harmful amounts of nitric and sulfuric acids formed primarily by nitrogen oxides and sulfur oxides released into the atmosphere when fossil fuels are burned. It can be wet precipitation (rain, snow, or fog) or dry precipitation (absorbed gaseous and particulate matter, aerosol particles or dust). Acid rain has a pH below 5.6. Normal rain has a pH of about 5.6, which is slightly acidic. The term pH is a measure of acidity or alkalinity and ranges from 0 to 14. A pH measurement of 7 is regarded as neutral. Measurements below 7 indicate increased acidity, while those above indicate increased alkalinity.

  • Acquired Capacity Agreement

    Under capacity release, an agreement between a gas pipeline and an acquiring shipper which establishes the terms and conditions for the acquiring shipper using firm capacity rights from a releasing shipper.

  • Acquiring Shipper

    In the context of capacity release, a shipper who acquires firm capacity rights from a releasing shipper (also known as "replacement shipper").

  • Acre-Feet

    The amount of water it takes to cover one acre to a depth of one foot. This measure is used to describe the quantity of storage in a hydrosystem reservoir. An average household of four will use approximately one acre foot of water per year.

  • Actual Interchange

    Metered electric power that flows from one control area to another.

  • Actual Peak Reduction

    The actual reduction in annual system peak load (measured in kilowatts) achieved through consumer's participation in a utility DSM (See Demand Side Management) program. It reflects the changes in the demand for electricity resulting from a utility DSM program that is in effect at the same time the utility experiences its annual system peak load, as opposed to the installed peak load reduction capability (i.e. potential peak reduction).

  • Actual Unit Starts

    Number of times the unit was synchronized.

  • Actuals

    In the context of futures trading, actual cash commodities in contrast to futures commodities. In the context of ratemaking, actual costs and throughput data relating to a given time frame.

  • Ad Valorem Tax

    Tax imposed at a percent of a value. Local property taxes are often ad valorem taxes.

  • Adequacy

    A bulk electric power system's ability to supply the aggregate electrical demand and energy requirements of customers at all times.

  • Adequate Regulating Margin

    The minimum on-line capacity that can be increased or decreased to allow the system to respond to all reasonable demand changes in order to be in compliance with the NERC Control Performance Criteria. See Spinning Reserves.

  • Adjacent System or Adjacent Control Area

    Any system or control area either directly interconnected with or electrically close to (so as to be significantly affected by the existence of) another system or control area.

  • Adjustment Clause on Provision (Rate Adjustment, Fuel Adjustment, Purchased Gas Adjustment, Tax Adjustment, Commodity Adjustment)

    A provision in a utility tariff that provides for changes in rates or total charges with changes in specified items of cost, such as No.2 or 6 fuel price, purchased gas, tax, etc.

  • Administrative-and-General Overhead (A&G) Costs


  • Age

    The number of years the unit(s) has been in commercial service.

  • Agency Service

    An arrangement which allows a gas buyer to give an agent authority to act on the buyer's behalf to arrange or administer pipeline transportation and/or sales services.

  • Aggregative Schedule

    A coordination requirement which calls for identification of the purchasing-selling entities that "aggregate" an interchange schedule.

  • Aggregator

    A company that consolidates a number of individual users and/or supplies into a group.

  • Air Conditioning Cycling Program

    A demand-side management program in which the utility remotely controls customers' cooling equipment and periodically interrupts power to the equipment during times of high power system demands.

  • Alliance

    An agreement among businesses, organizations, or group to work cooperatively toward a common purpose.

  • Allowance for Funds

    Used During Construction (AFUDC) A non-cash accounting convention of regulatory utilities that represents the estimated composite interest costs of debt and a return on equity funds used to finance construction. The allowance is capitalized in the property accounts and included in income.

  • Alternate Firm Receipt/Delivery Point

    Firm receipt or delivery point, not including primary points designated in a gas contract, at which a firm shipper may schedule gas receipt or delivery with a priority above that of interruptible service.

  • Alternate Fuel Capability

    The ability of any user such as an industrial facility to use more than one fuel, whether or not the facilities for such use have actually been installed.

  • Alternating Current (AC)

    A periodic current, the average value of which over a period is zero. Unless distinctly specified otherwise, the term refers to a current that reverses its direction at regularly recurring intervals of time and that has alternately positive and negative values. Almost all electric utilities generate AC electricity because it can easily be transformed to higher or lower voltages.

  • Alternating Current Distribution

    The supply of electrical energy from one or more major receiving stations to the point of ultimate utilization. The energy is generally supplied at a voltage that can be directly utilized by large rotating machinery and step-down transformers are utilized to reduce the voltage for most commercial or residential utilization.

  • Alternative Delivery Procedure (ADP)

    A futures contract provision in which buyers and sellers make and take delivery under terms and conditions which differ from those imposed in the futures contract.

  • Alternative Fuel Capacity

    The on-site availability of apparatus to burn more than one fuel.

  • American National Standards Institute (ANSI)

    The coordinating organization for U.S. federated national standards system. The ANSI federation consists of 1400 company, organization, government agency, institutional and international members.

  • Ampere (Amp)

    The unit of measurement of electrical current produced in a circuit by 1 volt acting through a resistance of 1 ohm. The measure of the rate of flow of electrons past a given point in an electric conductor such as a power line.

  • AMR

    Automated Meter Reading.

  • Ancillary Services

    Interconnected Operations Services identified by the Federal Energy Regulatory Commission (Order No. 888 issued April 24, 1996) as necessary to effect a transfer of electricity between purchasing and selling entities and which a transmission provider must include in an open access transmission tariff.

  • Annual Effects

    The total effects in energy use (measured in kilowatt-hours) and peak load (measured in kilowatts) caused by all participants in the DSM programs that are in effect during a given period.

  • Anthracite Coal

    A form of coal often referred to as "hard coal," which is generally used in the production of steel, characterized by low volatile matter, low sulfur, low ash, low Hargrove index (indicating a hard coal) and high heating value. Sometimes blended with bituminous coal in sized coal cargoes to increase heating value. Heating value is often at or above 13,500 Btu/lb.

  • APA

    Alaska Power Administration. A power marketing and electric transmission agency of the United States government with headquarters in Juneau, Alaska.

  • Application Service Provider (ASP)

    A company that provides businesses with access to application programs via the Internet. The application resides on the ASP's site and the user organization pays a license fee or some other usage charge.

  • Arbitrage

    Trading the same security, currency, or commodity in two or more markets in order to profit from differences in prices.

  • Arbitrageur

    An arbitrageur takes advantage of momentary disparities in prices between markets. Arbitrageurs make markets more efficient by bringing the prices in line with each other.

  • Area Control Error (ACE)

    The instantaneous difference between actual and scheduled power flow between two entities.

  • As-Billed

    The methodology in natural gas pipeline rate design in which all charges that the pipeline paid for transportation, transition costs, etc., pass through to its customers in the same form, demand or commodity, by which those costs were charged to the pipeline,

  • Asked

    The average price asked by those persons recently willing to sell a commodity or over -the-counter stock. Bid is the purchase price and asked is the selling or offer price.

  • Asset

    An economic resource, tangible or intangible, which is expected to provide benefits to a business.

  • Asynchronous

    Not in sync - usually applied to rotating equipment which generates power at a different frequency than the power grid. Synchronization with the grid is obtained through solid state inverters.

  • At-Risk Condition

    A condition placed upon certificates of Public Convenience and Necessity issued by the FERC which places the responsibility for under-recovery of costs regarding pipeline expansion or new construction on the pipeline sponsor and/or new customers, rather than on the pipeline's other customers.

  • At the Market

    In futures trading, the placement of an order immediately at the best price available on the trading floor.

  • At-the-Money Option

    Describes the price relationship of an option's strike price and the current market price of the underlying instrument. A call or a put option is said to be "at-the-money" when the option's strike price equals the current market price of the underlying instrument.

  • Atmospheric Pressure


  • Attempted Unit Starts

    Number of attempts to synchronize the unit after being shut down. Repeated failures to start for the same cause, without attempting corrective action, are considered a single attempt.

  • Auger Mining

    A coal mining process used to recover coal that is otherwise difficult or impossible to access, due to high cover or where pre-existing (Civil War, etc.) mine works make the coal too hazardous to recover. An auger is similar in appearance to a large wood drill, and several augers can be attached one to the other to a length of up to 250 feet, although 200 feet of depth is generally considered the practical maximum depth of drilling. This is inexpensive mining, but is not favored by many landowners, who want the maximum amount of coal taken from their reserve.

  • Automatic Generation Control (AGC)

    Equipment which automatically adjusts an electric power control area's generation from a central location.

  • Automatic Operating Systems

    Special protection systems (or remedial action schemes) or other operating systems installed on the electric systems that require no intervention on the part of system operators for their operation.

  • Availability

    Unit of measure for the actual time a transmission line or generating unit is capable of providing service, if called upon.

  • 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.

  • Available Hours

    Sum of all Service Hours, Reserve Shutdown Hours, Pumping Hours, Synchronous Condensing Hours; or Period Hours less Planned Outage Hours, Forced Outage Hours, and Maintenance Outage Hours.

  • Available Resource

    Sum of all capacity to which an entity has a legal right including Existing Generating Capacity, New Units Scheduled for Service, the NET of Equivalent Firm Capacity Purchases and Sales less Existing Capacity Unavailable Due to Planned Outages

  • Available Transfer Capability (ATe)

    Unit of measure for the transfer capability remaining in the physical transmission network for further commercial activity, over and above committed uses.

  • Average Annual Megawatt or Average Megawatt (aMW)

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

  • Average Cost Pricing

    A pricing mechanism based on dividing the total cost of providing electricity incurred in a period by the number MWh (wholesale) and kWh (retail) sold in the same period.

  • Average Demand

    The measure of the total of energy loads placed by customers on a system divided by the time period over which the demands are incurred.

  • Average Revenue per Kilowatt-hour

    Calculated by dividing the total monthly revenue in any given period by the corresponding total kWh sales.

  • Average Revenue per Unit of Gas Sales (By Class of Service)

    Revenue from the sale of natural gas to a class of service, exclusive of penalties and forfeited discounts, divided by the corresponding number of units sold. Units may be therms, Btu, or cubic feet.

  • Average Temperature

    The calculated average of the twenty-four hourly dry bulb atmospheric temperatures in degrees Fahrenheit recorded for each day. See MEAN TEMPERATURE.

  • Avoided Cost

    The cost to produce or otherwise procure electric power that an electric utility does not incur because it purchases this increment of power from a qualifying facility (QF). It may include a capacity payment and/or an energy payment component.