The amount of fuel necessary to generate one kilowatt-hour of electricity.

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

An exterior door that protects the primary door.

A tubular material used to encase and protect one or more electrical conductors.

Any material that can be burned to make energy.

A device used to maintain a specified humidity in a conditioned space.

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 ...

A valve operated by a thermostat that can be installed in solar water heating systems to mix cold water with water from the collector loop to maintain a safe water temperature.

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

An air conditioning system that has two ducts, one is heated and the other is cooled, so that air of the correct temperature is provided by mixing varying amounts of air from each duct.

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 ...

Large, flat boxes with glass covers and dark-colored metal plates inside that absorb and transfer solar energy to a heat transfer fluid.

A type of heating system in which the heat transfer fluid circulates from the heating component to a heat exchanger that is immersed in a heat storage media, passing its heat to the storage media without physically contacting it.

A term used to describe short and long-term affects on the Earth's climate as a result of human activities such as fossil fuel combustion and vegetation clearing and burning.

Fuels formed in the ground from the remains of dead plants and animals. It takes millions of years to form fossil fuels. Oil, natural gas, and coal are fossil fuels.

A type of anaerobic digester that has a mechanical mixing system and where temperature and volume are controlled to maximize the anaerobic digestion process for biological waste treatment, methane production, and odor control.

An open-loop solar heating system in which the heat transfer fluid from the collector loop and the piping drain into a drain whenever freezing conditions occur.

Water heated for residential washing, bathing, etc.

The outer casing of a window that sits in a designated opening of a structure and holds the window panes in place.

A hydrocarbon gas, C3H8, occurring in crude oil, natural gas, and refinery cracking gas. It is used as a fuel, a solvent, and a refrigerant. Propane liquefies under pressure and is the major component of liquefied petroleum (LPG).