Every day, the sun delivers enough energy to power the world for eight years, free of charge. The oceans of the world are buffeted by winds strong enough to match the output of several nuclear power stations. Meanwhile, the planet radiates around four times more heat into the atmosphere than humanity currently uses. Until now, the energy potential of these free and renewable power sources has largely been allowed go to waste. In Germany as well as in Europe as a whole, only around 6 per cent of the total energy used is currently generated via renewable sources. However, recent years in Germany have seen an unprecedented rise in the environmentally-friendly market sector, not least because of governmental measures designed to boost the share of renewable energy in the current energy mix to 10 per cent by 2020. The most significant of these is a set of renewable energy laws, designed to benefit wind-generated energy providers.
The capacity for electricity generation through wind energy within the EU has increased by more than 150 per cent since 2000, according to the European statistics body Eurostat. This upswing has been powered mainly by the wind turbines located in Denmark, Spain and Germany, which together account for some 80 per cent of the EU's wind energy capacity. In Germany around 4.3 per cent of electricity generated comes from wind. There are also plans to erect offshore wind turbine «parks» in order to utilise this renewable resource even further. The potential is huge: According to the environmental organisation Greenpeace, wind turbines covering just 3 per cent of Europe's ocean surface area would be capable of generating some 30 per cent of European energy needs.
Hydro-electric power accounts for the largest share of EU energy generated by renewable means, at around 18 per cent of total electricity output. In Germany the figure is 3.5 per cent, putting this source into second place in terms of renewable sources, just behind wind power. One of the greatest advantages of hydropower is also one of its drawbacks - hydro-electric plants require water to be stored in large reservoirs, and this can sometimes involve destroying large areas of settled land and open countryside.
The most varied renewable energy source is biomass. The burning of wood for energy purposes - a widespread practice in Africa - comes under this heading too, but it cannot be considered a genuinely «green» energy source. Other biomass fuels such as bio- diesel (made from rapeseed) or methane biogas (from liquid manure) are far more promising. Some 1,900 German fuel stations already offer bio-diesel, while the popularity of biogas systems is also rising. Around 2,700 such systems are in operation in Germany, more than three times the number counted in 1999.
When researchers presented the first working solar cell in 1954, many regarded the novel «sun battery» as little more than a curiosity. Since then experts have estimated that the energy emitted by the sun could produce nearly four times world's power requirements - assuming it could be harnessed properly. Today Germany is one of the world's largest markets for photovoltaics - devices which turn light into electricity. In 2005, solar energy generated more than one billion kilowatt hours of electricity, triple the amount produced in 2003. However, even this is just a fraction of total needs. The expense of solar energy has previously limited its usage, although the current boom in the sector should help to cut costs.
Practically inexhaustible and available the world over is geothermal energy which utilises the heat stored under the earth's surface. Iceland, for example, sources almost its entire energy needs from hot springs rising from the depths of the earth. In central Europe, the temperature rises around 3 degrees Celsius for every 100 metres travelled towards the Earth's core. The most significant advantage of this energy source is that it is available everywhere, irrespective of weather conditions. Germany is still in the early stages when it comes to geothermal energy and in 2005 it accounted for only 1 per cent of energy provision.
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