Green Industry : Glossary

There are 76 documents in this section.

  • Tidal/wave power

    6 November 2000

    Power that can be generated in coastal locations from the twice-daily ebb and flow of the tides. As the tide rises, water is allowed to flow through gates in the dam to fill the basin behind it. At high tide the gates are closed and as the tide falls the water in the basin is retained behind the dam. Once a sufficient head of water is built up, the water behind the dam is released and the potential energy it possesses is converted into kinetic energy which drives generators to produce electricity.

  • Turbine

    6 November 2000

    Rotary engine that converts the energy of a moving stream of water, steam, or gas into mechanical energy. The basic element in a turbine is a wheel or rotor with paddles, propellers, blades, or buckets arranged on its circumference in such a fashion that the moving fluid exerts a tangential force that turns the wheel and imparts energy to it. This mechanical energy is then transferred through a drive shaft to operate a machine, compressor, electric generator, or propeller. Turbines are classified as hydraulic, or water, turbines, steam turbines, or gas turbines. Today turbine-powered generators produce most of the world's electrical energy. Windmills that generate electricity are known as wind turbines.

  • Waste-to-energy incinerator

    6 November 2000

    An incinerator that uses waste products as fuel, to provide energy for space or water heating. Various types or refuse are used, from simple paper products to plastic and scrap car tyres. In many cases they are used as fuel supplements, since on their own they have an energy content that may be only 30 to 50 per cent that of solid fuels.

  • Wind energy

    6 November 2000

    Energy from moving air which is converted to electricity, by using wind to turn electricity generators. Wind energy has a number of advantages over conventional forms of energy. It is pollution-free and renewable.

  • Wind farm

    6 November 2000

    A cluster of wind turbines (up to several hundred) for generating electrical energy, erected in areas where there is a nearly steady prevalent wind; such areas generally occur near mountain passes.

  • Energy budget

    3 November 2000

    An accounting of the flow of energy through a system. Originally applied by ecologists to ecosystems, the approach is also useful in industry to check the energy efficiency of industrial processes.

  • 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.

  • 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.

  • Non-renewable resource

    3 November 2000

    A natural resource that cannot be replaced after it has been consumed. It applies particularly to fossil fuels, which can only be used once, but it also describes other mineral resources that are present in only fixed quantities in the earth's crust, although metals can be reused through recycling. Central to the concept is human time frame. Oil and natural gas are being formed beneath the earth's surface at present and new mineral ores are also being created. However, replacement may take millions of years, and society can consume them much more rapidly that they can be replaced. Thus in human terms they are effectively non-renewable.