Renewable Energy Review: Geothermal

What is it? Geothermal energy is derived from the heat of the Earth itself. It can be sourced close to the Earth’s surface, eliminating the need for excessive and destructive digging. However, the heat source itself is derived from deep within the Earth’s core—around 4,000 miles down. At this part of the planet, temperatures may reach over 9,000 degrees Fahrenheit. The heat emanates from the core to the surrounding rock. Humans have utilized geothermal energy for millennia—it is the cause of hot springs, and ancient Romans harnessed its power for space heating.


How is it sourced? Geothermal power plants harness these heat sources to generate electricity. There are three types of power stations—dry steam, flash steam, and binary cycle power stations.


How is it used? Geothermal energy can be part of a commercial utility energy solution on both large and small scales. This may include everything from heating office buildings and manufacturing plants to growing greenhouse plants. It can also be used to heat water at fish farms and aid in several industrial processes, such as pasteurizing milk.


Are there any downsides? Geothermal energy, though sustainable, can cause some minor environmental issues. In the most extreme cases, geothermal power plants can cause small earthquakes. Moreover, there are very heavy costs associated with building and developing geothermal power plants, and the energy availability is highly location-specific. This type of power is only sustainable if the reservoirs are properly managed.