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Access
The contracted right to use some or all of a transmission or distribution system to transfer electricity or gas. Access can apply to either an energy producer or an energy consumer.

Access Charge
A fee charged for the right to send or receive power over another party’s transmission or distribution system.

Acid Rain
Also called acid precipitation. Rainfall having an abnormally low pH, between 2 and 5, due to atmospheric water vapor combining with higher than normal amounts of nitrogen and sulfur oxides (from both man-made and natural sources) to form sulfuric or nitric acid.

Acre-foot
A British measure of water volume. The amount of water it takes to cover an area of 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 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).

Adjustment Clauses (Rate Adjustment, Fuel Adjustment, Tax Adjustment, Commodity Adjustment)
A provision in a utility tariff which provides for periodic changes in rates or total charges to a customer due to increases or decreases in certain costs (such as fuel, purchased gas, tax, etc.) over or under those included in the base rates.

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

Air Conditioning
Cooling and dehumidifying the air in an enclosed space by use of a refrigeration unit powered by electricity or natural gas.

Air Conditioning Equipment
Either a central system, window or wall units that cool the air in a structure by a refrigeration unit powered by electricity or natural gas. This definition excludes fans, blowers, or evaporative cooling systems (swamp coolers) that are not connected to a refrigeration unit.

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.

Air Quality Standard
The prescribed level of a pollutant in the outside air that cannot be exceeded during a specified time in a specified geographical area. Established by both federal and state governments to protect the people and the environment.

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

Alliance to Save Energy
A nonprofit coalition of business, government, environmental and consumer leaders who promote energy efficiency worldwide.

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.

Alternating Current (AC)
An electric current that reverses its direction of flow at regularly recurring intervals. Almost all electric utilities generate AC electricity because it can easily be transformed to higher or lower voltages.

Ambient Air
Any portion of the atmosphere not confined by four walls and a roof; outside air.

American National Standards Institute (ANSI)
The coordinating organization for U.S. federated national standards system. The ANSI Federation consists of approximately 1,000 businesses, professional societies and trade associations, government agencies, institutes and consumer and labor interests.

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.

APPA
American Public Power Association. The trade association of publicly-held power entities.

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.

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

Assistance for Heating in Winter
Assistance from the Low-Income Home Energy Assistance Program (LIHEAP). The purpose of LIHEAP is to assist eligible households to meet the costs of home energy, i.e., a source of heating or cooling residential buildings.

Assistance for Weatherization of Residence
Households receive services free, or at a reduced cost, from the federal, state, or local government. Services may include insulation, repair broken windows or doors, weather-stripping or caulking around windows/doors, furnace
tune-up and other home energy-saving devices.

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.

Atmospheric Pressure
See PRESSURE, ATMOSPHERIC.

Atom
The smallest particle of an element that cannot be divided or broken up by chemical means. It consists of a central core called a nucleus, which contains protons and neutrons. Electrons revolve in orbits in the region surrounding the nucleus.

Atomic energy
See nuclear energy.

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.

Automated Distribution
The automated distribution systems provide monitoring, control, and information on distribution equipment which includes switches, capacitors, protection devices, voltage regulation devices, and devices on the customer site. Customer site devices might include generation, demand-side management equipment, capacitors, high-speed switching devices, and any other power quality and/or reliability devices that are connected to the distribution system.

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.

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 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.