SMOLT -- A juvenile salmon or steelhead migrating to the ocean and undergoing physiological changes to adapt its body from a freshwater to a saltwater environment.

SPAWNING -- The releasing and fertilizing of eggs by fish.

SPILL -- Water passed over a spillway without going through turbines to produce electricity. Spill can be forced, when there is no storage capability and flows exceed turbine capacity, or planned, for example, when water is spilled to enhance juvenile fish passage.

SPILLWAY -- Overflow structure of a dam.


STORAGE RESERVOIRS -- Reservoirs that have space for retaining water from springtime snowmelts. Retained water is released as necessary for multiple uses -- power production, fish passage, irrigation, and navigation.

STRANDED COSTS -- The cost of generating facilities or other obligations that may not be competitive in today's market. For example, let's say a utility built a power plant specifically to serve a large factory. With deregulation, if the people running that factory decide to buy cheaper power somewhere else, the utility's power plant would become a stranded cost. In other words, the higher cost of that power plant will have to be collected from somebody else.

STREAMFLOW -- The rate at which water passes a given point in a stream, usually expressed in cubic feet per second (cfs).

SURPLUS ENERGY -- Energy generated that is beyond the immediate needs of the producing system. This energy may be sold on an interruptible basis or as firm power.

THERMAL POWER PLANT -- A facility that uses heat to power an electric generator. The heat may be supplied by burning coal, oil, natural gas, biomass or other fuel, by nuclear fission, or by solar or geothermal sources.

TRANSMISSION GRID -- An interconnected system of electric transmission lines and associated equipment for the transfer of electric energy in bulk between points of supply and points of demand.

TRANSMISSION SYSTEM -- The system of power lines used to transport electricity over long distances. In the Pacific Northwest, BPA operates a majority of the high-voltage power lines that carry electricity between points of supply and points of demand. The main BPA lines crossing the Cascades carry power at 500,000 volts. The transmission lines that move power from BPA's delivery point to PUD substations carry power at 115,000 volts.

TURBINE -- Machinery that converts kinetic energy of a moving fluid, such as falling water, to mechanical or electrical power.

VOLT -- The unit of measurement of electromotive force. It is equivalent to the force required to produce a current of one ampere through a resistance of one ohm.

WASHINGTON PUD ASSOCIATION -- An organization that represents the interests of the Public Utility Districts in the state.

WATER BUDGET -- A part of the Northwest Power Planning Council's Fish and Wildlife Program calling for a volume of water to be reserved and released during the spring, if needed, to assist in the downstream migration of juvenile salmon and steelhead.

WATT -- An electric unit of power or a rate of doing work (see kilowatt and megawatt).


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