Renewable energy

Renewable Energy is energy derived from resources that are regenerative or for all practical purposes cannot be depleted. For this reason, renewable energy sources are fundamentally different from fossil fuels, and do not produce as many greenhouse gases and other pollutants as fossil fuel combustion.

Mankind's traditional uses of wind, water, and solar energy are widespread in developed and developing countries; but the mass production of electricity using renewable energy sources has become more commonplace recently, reflecting the major threats of climate change, exhaustion of fossil fuels, escalating electricity price levels, and the environmental, social and political risks of fossil fuels. Consequently, many countries promote renewable energies through tax incentives and subsidies.

Historically, low fossil fuel prices, especially for natural gas, have made growth difficult for renewable fuels.

Renewable energy accounts for about 10% of the world's primary energy supply, but the technical potential is large enough to cover even the projected energy consumption in 2100 many times over. Renewable technologies such as geothermal and hydropower are often economically competitive with nonrenewable energy sources. Other technologies such as solar power are more expensive, although future costs may decline to a fraction of current levels.

There are five main sources of renewable energy used most often:

- hydropower (water),

- solar,

- wind,

- geothermal,

- biomass.

While currently renewable energy sources only supply a modest fraction of current energy use (approx. 14% of primary energy use, mostly from traditional biomass), there is much potential within this area that could be exploited in the future. As the table below illustrates, the technical potential of renewable energy sources is more than 18 times current global primary energy use and furthermore several times higher than the projected energy use in 2100. Needless to say, renewable energy and energy efficiency technologies are pivotal to creating an environmentally friendly future for the world.

[Sources: Wikipedia, Energy Information Administration, Annual Energy Review, August 2006.]