Renewable energies: what technologies currently exist?

The nuclear accident in Fukushima is rekindling the debate on alternative energy sources. The European Union wants 20% of its energy to come from renewable sources by 2020 – up from the current 9%. On 22 March members of the Industry, Research and Energy Committee discussed a study on available technologies. A brief overview of the energy sources of the future.

Offshore wind power

Wind turbines can be built at sea, where the wind is stronger than on land. Wind farms are being developed offshore, but this technique is still at a very early stage of commercialization. In the medium term, the cost of this electricity could fall below the cost of traditional wind power, due to better yields. Currently, the cost of construction is higher.

Thermodynamic solar power plants

Mirrors concentrate sunlight into a heat transfer fluid, whose heat is then transformed into electricity by a generator. Some experts estimate that this technique could supply up to 3% of European consumption by 2020.

Bio-energy

This is the use of energy stored by biomass. For example, it is possible to recover the gas emitted by decomposing organic waste. However, its potential is lower than wind or solar power.Wave energy. The ripples of the ocean swell or waves produce energy that can be captured either by machines on the surface or by underwater pressure variation sensors. The energy produced could be of the same order of magnitude as the world’s total consumption. Nevertheless, this technology raises many environmental issues.

Geothermal energy

The difference in temperature between the Earth’s surface and the heat reserves located deep underground (the geothermal gradient) causes the release of thermal energy. However, the costs of capturing this energy are too high for it to be commercialized – unless major technological developments take place.

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