Renewable energy sources can be found in sunlight (solar), in the air (wind power), deep underground, in our rivers and in our oceans. These are part of the structure of the planet which means that they are continuously being renewed naturally and cannot be depleted.
There are five types of alternative energy which is being generated and harnessed naturally (good examples are the sun and waves) which are usually the most sustainable forms of energy.
Sunlight is a renewable source of energy and its most direct use is achieved by capturing the energy of the sun. A wide range of solar energy technologies are being incorporated to convert the sun’s light and energy into heat, hot water, electricity and illumination as well as cooling systems for industries and businesses. Photovoltaic systems use solar cells to convert sunlight into energy.
Since May 2009 eighty countries have agreed to use wind power commercial. South Africa’s first commercial wind farm was established in Darling close to Cape Town in 2008. Wind flow is captured by wind turbines and converted into electricity. On a much smaller scale, windmills are used to pump water on farms. Commercial-grade wind-powered generating systems can meet the renewable energy needs of numerous organisations.
Geothermal power – power from the Earth
Geothermal energy is derived from the Earth’s heat which can be sourced close to the surface or from heated rock and reserves of hot water beneath the Earth’s surface. Geothermal energy can form part of a commercial utility energy solution on a large scale or can form a portion of a sustainable practice on a local level.
Hydropower has been in use throughout the ages by using waterwheels. The kinetic energy of flowing rivers is captured and converted into hydroelectricity. Probably the most familiar type of hydroelectric power is generated by a system where dams are constructed to store water in reservoirs which, when released, flows through turbines to produce electricity.
Thermal Ocean Energy and Tidal and Wave Power
The ocean produces two kinds of energy – these are thermal ocean energy which is energy from the sun’s heat and mechanical energy from the motion of tides and waves.
Because of a shortage of non-renewable resources, we must consider using alternative sources of energy such as wind and solar power, geothermal power, hydroelectricity, thermal ocean energy and tidal and wave power.