Renewable energy

This article is part of the Living together theme Alternative economy Degrowth Alternative societies Social Politics Communication Environment Renewable energy Naturism

Renewable energy is a phrase used to qualify energy resources that naturally replenish themselves relatively quickly as opposed to fossil fuels such as oil or gas that are finite resources. These resources include but are not limited to solar power, wind power, tidal power, hydropower, geothermal heating and biomass. Climate change concerns as well as oil prices are two of the main reasons why these renewable energy resources are more and more important.

[edit] Wind power

This consists in harnessing airflows by the means of a turbine that converts the kinetic energy into usable energy. This is one of the oldest forms of energy sources and was used as far back as 1st century AD by Heron of Alexandria to power a machine that played music. Later, more extensively for the purpose of milling flour. Modern wind turbines range from around 600KW to 5MW of rated power, although the energy is dependant on the windspeed. Off shore, shoreline and high altitude areas are of particular interest because there are substantially higher wind speeds in these areas. Wind power produces no greenhouse gases during operation. Small wind turbines can be purchased to generate energy for individual households.

[edit] Hydropower

There are many different ways to harness the power of water to produce electricity.

The conventional method is through the use of dams which harness the potential energy of vast amounts of water to spin a turbine. The biggest concern with this method is the large amounts of land that must be inundated to produce adequate amounts of energy. These installations are also very expensive and often far from where the power is needed ; they also imply greenhouse gases with methane generated from decomposing plant matter inside the inundated land. The Three Gorges Dam in China is the largest example of hydroelectric dams with a capacity of 22,500 MW.

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