The ratio of fuel energy input as heat per unit of net work output; a measure of a power plant thermal efficiency, generally expressed as Btu per net kilowatt-hour.

In reference to a wind energy conversion system, the area of a turbine blade surface that first comes into contact with the wind.

A heating system that uses only outside air for combustion and vents combustion gases directly to the outdoors. These systems are less likely to backdraft and to negatively affect indoor air quality.

An electricity generating facility that uses geothermal energy.

Energy produced by the conversion of biomass directly to heat or to a liquid or gas that can be converted to energy.

A measure of the average amount of a specified pollutant or material emitted for a specific type of fuel or process.

Solar collector thermal performance ratings based on collector efficiencies, usually expressed in Btu per hour for solar collectors under standard test or operating conditions for solar radiation intensity, inlet working fluid temperatures, and ambient te ...

This is a national organization dedicated to representing the interests of cooperative electric utilities and the consumers they serve. Members come from the 46 states that have an electric distribution cooperative.

Energy output from a system that equals energy input.

The ratio of the percentage change in the quantity of a good or service demanded to the percentage change in the price.

The generation of an electric current, when two conductors of different metals are joined at their ends to form a circuit, with the two junctions kept at different temperatures.

The rate of heat flow required to maintain a specific indoor temperature; usually measured in Btu per hour.

Material such as brick, rock, or stone.

The change in direction of a ray of light when it passes through one media to another with differing optical densities.

A device or media that absorbs heat for storage for later use.

The area of glass that fits in the window frame.

A valve used to mix heated water with cold in a heating system to provide a desired water temperature for end use.

Power generated by a utility unit that operates at a very low capacity factor; generally used to meet short-lived and variable high demand periods.

The process of producing electricity by transforming other forms or sources of energy into electrical energy; measured in kilowatt-hours.

In a given electrical circuit, the amount of current in amperes (i) is equal to the pressure in volts (V) divided by the resistance, in ohms (R).