Zusammenfassung der Ressource
Energy Sources
- Fossil Fuels
- All energy ultimately comes from either the sun or the Earth
- Fuel is any material that is burned or altered in order to obtain energy
- Food is clearly a fuel
- Wood, dung and animal fat were early fuels, burned by our prehistoric ancestors to create heat and possibly light
- Fossil fuels are those formed over geological time from the partly decayed remains of plants or animals.
- They include coal, oil and natural gas.
- They can be used or combusted only once and are therefore finite
- They become exhausted because they can only be replaced over considerable periods of geological time
- They are classified as non-renewable sources of energy
- During combustion, fossil fuels produce carbon dioxide, which has an impact on climate because it contributes to the greenhouse effect
- Exploiting fossil fuels by quarrying, mining and pumping has other environmental
impacts, such as deforestation and the disruption of water tables and groundwater
supplies
- Nuclear energy falls into the category of non-renewable
energy since supplies of the raw material, uranium, are finite
- Renewable Sources
- By contrast, renewable sources of energy are those
capable of natural regeneration on a human timescale
- They provide almost continuous flows of energy
- These sources include inland water, wind, the tides, ocean
waves, geothermal heat and the sun's rays
- Sustainable sources of energy include wood, which can be
regrown, and the pumped storage water of a hydroelectric
power plant, which can be used time and time again
- Some would also put nuclear energy in this category, because the
nuclear power industry is able to reprocess some spent fuel so that it can
be reused.
- Primary Energy Sources
- A distinction is made between primary and secondary energy
- Primary energy is the energy
found in natural resources
- Examples include coal, crude oil, sunlight, wind, rivers, vegetation and uranium
- Secondary energy is primary energy that has been converted into a more convenient form, usually electricity