GLOSSARY

(A-B)  (B-C)  (C-E)  (E-G)  (G-M)   (M-O)  (O-P)   (P-S)  (S-W)

ALTERNATING CURRENT (AC) -- An electric current in which the electrons flow in alternate directions. In North American electrical grids, this reversal of flow is governed at 60 cycles per second (Hertz).

ACRE-FOOT -- Volume covering one acre to a depth of one foot. This volume measurement is used to describe a quantity of storage in a reservoir.

AMERICAN PUBLIC POWER ASSOCIATION (APPA) -- An organization that represents the interests of publicly owned utilities throughout the United States.

ANADROMOUS -- Fish that hatch in fresh water, migrate to the ocean, mature there and return to freshwater to spawn. Salmon and steelhead, for example.

ANNUAL OPERATING PLAN -- A yearly plan for operating reservoirs on the Columbia River. Such a plan is specifically required by the Columbia River Treaty and by the Pacific Northwest Coordination Agreement.

ASSURED REFILL CURVE -- A curve showing minimum elevations that must be maintained at each project to ensure refill even if the third lowest historical water year occurred; it sets limits on the production of energy.

AVERAGE MEGAWATTS (aMW) -- The energy produced by the continuous operation of one megawatt of capacity over a period of one year. (One average megawatt is equivalent to 8.76 million kilowatt-hours)

AVOIDED COST -- A guideline for comparing the value of conservation and renewable resources with other resources. Literally, the cost a utility avoids by purchasing a conservation or renewable resource versus acquiring energy elsewhere.

BASELOAD -- In a demand sense, a load that varies only slightly in level over a specified time period. In a supply sense, a plant that operates most efficiently at a relatively constant level of generation.

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.

BLACKOUT -- An emergency forced outage or other fault in the generation, transmission or distribution system that causes the disconnection of the source of electricity from all the electrical loads in a certain geographical area.

BONNEVILLE POWER ADMINISTRATION -- BPA is the sole federal power marketing agency in the Northwest and the region's major wholesaler of electricity. Created by Congress in 1937, BPA serves the states of Washington, Oregon, Idaho, Montana west of the continental divide, and small adjacent portions of California, Montana, Nevada, Utah and Wyoming. BPA markets and transmits power, coordinates operations of the Federal Columbia River Power System, and manages a large portion of the Pacific Northwest-Pacific Southwest Intertie. Although it lacks authority to build or own dams or power plants, BPA does own and operate, within its service area, the nation's largest network of long distance transmission lines. Though part of the Department of Energy, BPA is not funded by tax revenues; the agency recovers the cost of operations and maintenance mainly through its electrcity rates.
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