Geothermal Energy is a renewable energy source that has been used for thousands of years.  Geothermal energy derives from harvesting Earth’s natural internal heat.  This heat is collected beneath Earth’s crust anywhere from shallow ground to miles beneath the surface.  This is a very clean source of energy since no fuel is burned.  Geothermal energy has become a popular source of energy in Iceland, as well as other renewable energies.

In Iceland, renewable energy accounts for roughly 85% of Iceland’s energy consumption and 66% of that being geothermal energy.  Iceland has unique geology has made it very easy and cheap to acquire renewable sources of energy.  Since Iceland is located on the Mid-Atlantic Ridge, which is one of the most tectonically active locations in the world, geothermal energy is quite abundant and easy to access.  In fact, there are over 600 hot springs and over 200 volcanoes located in Iceland.  The country became very involved in renewable energy after the second world war and it has ultimately changed the country and its economy as a whole.  The primary use of geothermal energy is keeping Iceland’s buildings and homes warm.  Geothermal energy is used to heat and cool 9 out of 10 buildings/homes.  Geothermal heat pump systems located in building/homes are used to moderate temperature.  The pump only penetrates the crust about 10 feet and is able to harness the constant temperature offered by the Earth’s surface and distribute the heat into buildings.  The pump can also work in reverse and extract heat from the building and transfer it into the ground during summer months.  Heat pumps are also commonly found in greenhouses allowing Iceland to grow crops when it’s too cold.

Geothermal energy is also used to generate electricity.  In order to produce electricity with geothermal energy, a well a mile deep or more is drilled into the ground.  These wells are drilled to access heat sources, like steam and very hot water, that will provide enough heat energy to spin turbines that are connected to electricity generators.  There are three different kinds of geothermal power plants which include; dry steam, flash, and binary.  Dry steam is the oldest geothermal technology and simply uses steam acquired from fractures in the ground and uses it to spin a turbine resulting in electrical generation.  Flash plants are slightly different.  These plants harvest the very hot water from underground reservoirs and mix the high-pressure hot water with low-pressure cooler water to create steam which then spins a turbine.  The latest technology is found in binary plants.  Binary plants acquire hot water, like flash plants, and pass it by a secondary fluid with a much lower boiling point that water, causing the secondary fluid to turn to vapor which is then used to spin a turbine.  Binary plants are the most modern and are most likely to be found recently established plants and plants that are to be built in the near future.    

Geothermal energy offers numerous advantages when compared to other common sources of energy.  For example, geothermal energy can be extracted without the burning of fossil fuels.  Binary plants are nearly 100% emission free, making geothermal energy an extremely ‘clean’ energy source.  Also, when looking at other renewable energy sources geothermal energy is available all day every day of the year, unlike wind and sunlight where the amount of free energy is limited.  Lastly, geothermal energy is relatively inexpensive.  Iceland has made itself a role model for other countries to look up to when it comes to efficiency and a cleaner future.