Renewable Energy : Glossary

There are 82 documents in this section.

  • Methane

    3 November 2000

    A simple hydrocarbon gas (CH4) produced during the decomposition of organic material under anaerobic conditions. It is the main constituent of natural gas and therefore and important fuel.

  • Natural gas

    3 November 2000

    A mixture of hydrocarbons in gaseous from, found in pockets beneath the earth's surface, usually in association with liquid petroleum products. It consists largely of methane (CH4) (c. 85 per cent), but contains other hydrocarbons such as ethane (CH6) and propane (C3H8), and was formed as the result of the anaerobic decay of organic matter.

  • 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.

  • Oil

    3 November 2000

  • OPEC

    3 November 2000

    Organisation of Petroleum Exporting Countries. A group of Middle Eastern, Asian, African and Latin American nations that includes the world's major petroleum producers and exporters. They came together in 1960, recognising the importance of oil as a source of future development, and with the intention of using their petroleum resources to advance their economic interests.

  • Petroleum

    3 November 2000

    A mixture of naturally occurring hydrocarbons, that may exist in a solid (e.g. bitumen), liquid (e.g. crude oil) or gaseous state (e.g. natural gas). It commonly contains variable amounts of other chemicals such as sulphur (S) and nitrogen (N). Petroleum is the end-product of the partial decay of living organisms which once inhabited the world's oceans. As they died they sank to the bottom of the oceans, where the anaerobic conditions allowed them to be preserved.

  • Fossil fuels

    22 August 2000

    Fuels such as coal, oil and gas made by decomposition of ancient animal and plant remains which give of carbon dioxide when burned.

  • Global warming

    22 August 2000

    The idea that increased greenhouse gases cause the Earth's temperature to rise globally.

  • Greenhouse effect

    22 August 2000

    The cause of global warming. Incoming solar radiation is transmitted by the atmosphere to the Earth's surface, which it warms. The energy is retransmitted as thermal radiation, but some of it is absorbed by molecules of greenhouse gases instead of being retransmitted out to space, causing the temperature of the atmosphere to rise. The name comes from the ability of greenhouse glass to transmit incoming solar radiation but retain some of the outgoing thermal radiation to warm the interior of the greenhouse. The 'natural' greenhouse effect is due to the greenhouse gases present for natural reasons, and is also observed for the neighbouring planets in the solar system. The 'enhanced' greenhouse effect is the added effect caused by the greenhouse gases present in the atmosphere due to human activities, such as burning of fossil fuels and deforestation.

  • Greenhouse gases

    22 August 2000

    Molecules in the Earth's atmosphere such a carbon dioxide (CO2), methane (CH4) and CFCs which warm the atmosphere because they absorb some of the thermal radiation emitted from the earth's surface.