A construction element used to cover the exterior of wall framing and roof trusses.

A tax credit granted for specific types of investments.

The ratio of average energy demand (load) to maximum demand (peak load) during a specific period.

The power required to energize the magnetic field of a generator.

An arrangement of photovoltaic cells or material mounted on a rigid flat surface with the cells exposed freely to incoming sunlight.

The ratio of actual power being used in a circuit, expressed in watts or kilowatts, to the power that is apparently being drawn from a power source, expressed in volt-amperes or kilovolt-amperes.

see Peak Watt.

A device in which organic material is biochemically decomposed (digested) by anaerobic bacteria to treat the material and/or to produce biogas.

To price and sell greenpower/electricity higher than that produced from fossil or nuclear power plants, supposedly because some buyers are willing to pay a premium for greenpower.

A solar energy system designed to provide heat to individual rooms in a building.

A type of furnace in which fuel is burned and the heat is used to produce steam.

The value or purchasing power of a dollar in a specified year carried forward or backward.

The tendency of the sunlight to electricity conversion efficiency of amorphous silicon photovoltaic devices to degrade (drop) upon initial exposure to light.

A measure of the quality of a light source by expressing the color appearance correlated with a black body.

Freshly cut, unseasoned, wood.

The process by which sunlight directly enters a building through the windows and is absorbed and stored in massive floors or walls.

A source of power (electricity) that can displace power from another source so that source's power can be transmitted to more distant loads.

The net south-facing glazing area projected on a vertical plane. Also, the solid area covered at any instant by a wind turbine's blades from the perspective of the direction of the windstream (as opposed to the swept area).

A solar thermal electric central reciever power plant ("power tower") located in Barstow, California, and completed in 1981. The Solar One had a design capacity of 10,000 peak kilowatts, and was composed of a receiver located on the top of a tower surroun ...

A coating applied to the surface of the glazing of a window to reduce heat transfer through the window.