That portion of an electricity supply system used to deliver electricity from points on the transmission system to consumers.

A solar heating system that uses a liquid as the heat transfer fluid.

A measure of the unavailable or unusable energy in a system; energy that cannot be converted to another form.

A method of financial and economic analysis used to determine present and future values of investments or expenses.

The air that is supplied to the combustion chamber of a furnace.

Wind turbines that operate at a constant rotor revolutions per minute (RPM) and are optimized for energy capture at a given rotor diameter at a particular speed in the wind power curve.

The region between an n-layer and a p-layer in a single material, photovoltaic cell.

A type of window glazing films used to block the infrared (heat) portion of the solar spectrum but admit a higher portion of visible light.

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

Freshly cut, unseasoned, wood.

A type of anaerobic digester that has a horizontal tank in which a constant volume of material is added and forces material in the tank to move through the tank and be digested.

A plot of a wind energy conversion device's power output versus wind speed.

see Solar Spectrum above.

The mean distance a free electron or hole moves before recombining with another hole or electron.

The percentage of a building's seasonal energy requirements that can be met by a solar energy device(s) or system(s).

The interior area of a building, calculated in square feet or meters.

A water and energy conserving device that limits the amount of water that a faucet or showerhead can deliver.

A renewable energy system that includes two different types of renewable energy technologies that produce the same type of energy; for e.g., a wind turbine and a solar photovoltaic array combined to meet a power demand.

A solid that contains pores; normally, it refers to interconnected pores that can transmit the flow of fluids. (The term refers to the aquifer geology when discussing sites for CAES.)

Usually refers to ethanol to 160 to 200 proof.