The average amount of solar radiation that reaches the earth's upper atmosphere on a surface perpendicular to the sun's rays; equal to 1353 Watts per square meter or 492 Btu per square foot.

Turbines in which the axis of the rotor's rotation is parallel to the wind stream and the ground.

The losses that result from inherent resistance in electrical conductors and transformation inefficiencies in distribution transformers in a transmission and distribution network.

A unit of mass equal to 1,000 kilograms or 2,204.6 pounds.

An exterior door that protects the primary door.

An empirical measure of the quantity of light. It is based upon the spectral sensitivity of the photosensors in the human eye under high (daytime) light levels. Photometrically it is the luminous flux emitted with a solid angle (1 steradian) by a point so ...

A turbine that generates power from the combustion of a fuel.

The ratio of power produced by a wind energy conversion device to the power in a reference area of the free windstream.

The two times of the year when the sun crosses the equator and night and day are of equal length; usually occurs on March 21st (spring equinox) and September 23 (fall equinox).

The process of modifying a building's structure.

The measure of closeness in shape between a waveform and it's fundamental component.

Glass, plastic panels, or plastic sheets that reduce air infiltration and some heat loss when attached to either the interior or exterior of existing windows.

A class of energy producer that produces both heat and electricity from a single fuel.

The nominal voltage for which a conductor or electrical appliance is designed; the reference voltage for identification and not necessarily the precise voltage at which it operates.

A hydropower facility that stores water in a reservoir during high-inflow periods to augment water during low-inflow periods. Storage projects allow the flow releases and power production to be more flexible and dependable. Many hydropower project operati ...

The total amount of electricity produced by a power plant.

The physical material upon which a photovoltaic cell is applied.

The amount of energy an energy storage device or system can store.

A measure of the probability that a system demand will exceed capacity during a given period; often expressed as the estimated number of days over a long period, frequently 10 years or the life of the system.

Transmit high-voltage electricity from the transformer to the electric distribution system.