Renewable energy is energy that is generated from natural processes that are continuously replenished. This energy cannot be exhausted and is constantly renewed.
Here are some examples of the most common forms of renewable energy.
Most commonly, wind energy systems generate electricity using large “windmill” turbines that use the moving air to power and electric generator that supplies and electric current.
Biomass, is a renewable organic matter, and can include biological material derived from living, or recently living organisms, such as wood, waste, and alcohol fuels.
Two main types of solar energy systems are in use today: photovoltaics, and thermal systems.
Solar photovoltaics systems are also known as Solar Cells and these devices convert light energy directly into electrical energy. The most common approach is to use silicon panels, which generate an electrical current when light shines upon it. You may have seen small solar cells on calculators or some mobile phones and most road signs use this method for power.
Solar panels are different to solar cells. Solar panels do not generate electricity directly. Solar thermal systems store heat from the sun that can be used in different ways. Fro example for heating water. Greenhouses are a good example of passive solar thermal design because they collect solar energy on sunny days and use it to keep it warm at night.
Hydro means "water" - so "hydro power" is energy made from water. This can be captured in dams where water moves from high ground to low ground and the speed of the water flow powers the generators or by wave power from the ocean driving energy to the hydro plant.
Wave power is the transport of energy by wind waves, and the capture of that energy to do useful work – for example, electricity generation, water desalination, or the pumping of water (into reservoirs).