Geothermal energy is the use of the heat energy generated from the earth. Geothermal energy is convenient in  that it is renewable and sustainable. This works by drilling into the ground to heated area, where water is pumped to create steam, the steam is then used to turn turbine and generate electricity.

Another way is to use the  magma. In 2009, researchers in Iceland, after accidentally drilling into a chamber of molten lava,  used the steam escaping the magma to generate electricity. The generated approximately 36 Megawatts of electricity.

Another way is to use geothermal plants which create approximately 5% of the carbon dioxide, 1% of sulfur dioxide, and less than 1% of the nitrous oxide emitted by coal-fire plant of equal size. There are certain types of geothermal plants that produce near-zero emissions.

 

Here is a video explaining how Geothermal-energy works in Iceland:

 

 

 

 

 

http://thinkprogress.org/climate/2014/02/04/3241811/iceland-geothermal-magma-energy/

http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/how-geothermal-energy-works.html#.VQ2BYY7F_Yw

http://geothermal.marin.org/pwrheat.html