Renewable energy is energy generated from natural resources such as Biomass , hydropower , Geothermal , Wind , Solar which are renewable (naturally replenished) . In 2006, about 18% of global final energy consumption came from renewables and it’s can be replenished in a short period of time
Wind energy :
Energy from Moving Air
Wind is simply air in motion. It is caused by the uneven heating of the Earth's surface by the sun. Because the Earth's surface is made of very different types of land and water, it absorbs the sun's heat at different rates. Today, wind energy is mainly used to generate electricity. Wind is a renewable energy source because the wind will blow as long as the sun shines.
Geothermal energy :
The word geothermal comes from the Greek words geo (earth) and therme (heat). So, geothermal energy is heat from within the Earth. We can recover this heat as steam or hot water and use it to heat buildings or generate electricity.
Geothermal energy is a renewable energy source because the heat is continuously produced inside the Earth.
Hydropower energy :
Energy From Moving Water
Hydropower is the renewable energy source that produces the most electricity in the United States. It accounted for 6% of total U.S. electricity generation and 67% of generation from renewables in 2008.
Solar energy :
Energy from the Sun
The sun has produced energy for billions of years. Solar energy is the sun’s rays (solar radiation) that reach the Earth. This energy can be converted into other forms of energy, such as heat and electricity. In the 1830s, the British astronomer John Herschel famously used a solar thermal collector box (a device that absorbs sunlight to collect heat) to cook food during an expedition to Africa. Today, people use the sun's energy for lots of things.
Biomass energy :
Biomass is organic material made from plants and animals. Biomass contains stored energy from the sun. Plants absorb the sun's energy in a proches called photosynthesis. The chemical energy in plants gets passed on to animals and people that eat them.
Biomass is a renewable energy source because we can always grow more trees and crops, and waste will always exist.