Geothermal

Iceland is one of the most dynamic volcanic regions in the world. Which explains why Iceland is a leader in geothermal energy and resources. Currently  30 percent of  Iceland electricity is generated through geothermal , according to Iceland’s National Energy Authority. When transportation, heating and production of electricity are considered as a whole, geothermal provides half of all the primary energy used in Iceland.

Iceland is optimal for geothermal power due to it’s large “underground reservoirs of water that are continually renewed by levels of annual precipitation that range as high as 177 inches (450 centimeters) over Iceland’s glaciers, and shallow plumes of magma that heat the deepest reaches of these reservoirs to temperatures in excess of 750 degrees Fahrenheit”,  according to scientificamerican.org.

Geothermal springs for power plants. The most common way of capturing the energy from geothermal sources is to tap into naturally occurring “hydrothermal convection” systems, where cooler water seeps into Earth’s crust, is heated up, and then rises to the surface. Once this heated water is forced to the surface, it is a relatively simple matter to capture that steam and use it to drive electric generators. Geothermal power plants drill their own holes into the rock to more effectively capture the steam.

Three basic designs for geothermal power plants,

• known as dry steam, the steam goes directly through the turbine, then into a condenser where the steam is condensed into water.
•  Flash depressurized water into steam which can then be used to drive the turbine.
•  binary cycle system, the hot water is passed through a heat exchanger, where it heats a second liquid—such as isobutane—in a closed loop.

http://www.scientificamerican.com/article/iceland-geothermal-power/

http://www.ucsusa.org/clean_energy/our-energy-choices/renewable-energy/how-geothermal-energy-works.html#bf-toc-1

http://www.nea.is/geothermal/