Renewable Energy : Glossary

There are 82 documents in this section.

  • Energy conservation

    3 November 2000

    Using less energy to achieve the same amount of work or decreasing the amount of fuel used to produce the same energy output. By reducing demand and improving energy efficiency, energy resources can be conserved.

  • Energy efficiency

    3 November 2000

    The percentage of total energy input that does useful work and is not lost or converted to low temperature, usually useless, heat. With the growing concern for declining energy resources, rising energy costs and the impact of large-scale energy consumption on the environment, the term refers to, for example, the willingness of society to change its user habits so that less energy is wasted.

  • Energy

    3 November 2000

    The capacity to do work. Energy takes a variety of forms and can be converted from one form to another to meet specific needs. There is no simple universally accepted classification of energy forms, but most classifications include:

    • kinetic - the energy possessed by an object in motion
    • potential - the energy possessed by an object as a result of its position. A bag of flour on a shelf, for example, retains the energy expended to place it in that position. If the bag falls off the shelf the potential energy will become kinetic energy.
    • thermal - heat energy
    • electrical - the energy associated with an electric charge in an electric field
    • chemical - the energy released during a chemical reaction
    • nuclear - the energy released during nuclear reaction
    • radiant - energy transmitted in the form of radiation
    Energy can be converted from one form to another. The chemical energy in coal, for example, is converted into thermal energy through combustion, which in turn can be converted into electrical energy in a thermal electric power station.

  • Ethanol

    3 November 2000

    Ethyl alcohol (C2H5OH). One of the most common alcohols, traditionally produced by fermentation of the natural sugars in grain and fruit, and the base for many alcoholic beverages.

  • Gasohol

    3 November 2000

    A mixture of gasoline (petrol) and ethanol or methanol used as a fuel for gasoline-powered motors. Since ethanol and methanol can be produced from waste agricultural and wood products, the production of gasohol has been seen as a means of reducing energy loss caused when these materials are discarded, while at the same time reducing the demand for gasoline.

  • Geothermal energy

    3 November 2000

    Energy available in the molten and semimolten rocks beneath the earth's crust. The high temperatures that this creates in adjacent solid rocks in certain areas causes sub-surface water to be superheated or converted into steam, which can be used for direct space heating or converted into electricity in a conventional power plant.

  • Fuel cells

    3 November 2000

    Fuel cells are electrochemical devices that convert a fuel's energy directly to electrical energy through a chemical reaction instead of combustion. Fuel cells operate much like continuous batteries when supplied with fuel to the anode (negative electrode). Fuel cells forego the traditional extraction of energy in the form of combustion heat, conversion of heat energy to mechanical energy (as with a turbine), and finally turning mechanical energy into electricity (e.g. using a dynamo). Instead, fuel cells chemically combine the molecules of a fuel and oxidizer without burning, dispensing with the inefficiencies and pollution of traditional combustion.

  • Household fuel

    3 November 2000

    Either gaseous (natural gas), liquid (fuel oil or kerosene) or solid (coal or wood) fuel used for domestic cooking and/or heating.

  • Hydro-power

    3 November 2000

    The use of water-power to generate electricity. Electricity produced by using the kinetic energy available in flowing water. Where the gradient of a stream is steep or a natural waterfall exists, the water can be directed through a turbine to drive an electric generator.

  • Kinetic energy

    3 November 2000

    The energy an object possesses as result of its motion. Kinetic energy is often produced by the conversion of other forms of energy. For example, the thermal energy obtained by burning coal can be used to produce steam that in turn provides kinetic energy through a mechanical device such as a piston engine or turbine. Moving fluids such as wind or water possess kinetic energy that can be used to drive windmills or hydroelectric generators.