Although our planet was formed billions of years ago, the Earth’s center is still very hot. Thankfully, radioactive decay will continue to heat the planet another few billion years through geothermal energy. Here’s what you need to know about this reliable, renewable resource that uses this heat to make clean electricity.


What is Geothermal Power?

  • While the Earth is hot underground, a geothermal reservoir must contain a special set of geologic characteristics: fluid, heat, and permeability. When developers explore for the perfect place to build their next geothermal power plant they are testing geologic structures for these three crucial geologic traits.
  • One of geothermal power’s biggest advantages is that it’s always The continuous flow of heat from the Earth ensures an inexhaustible and essentially limitless supply of energy. No need to worry about the sun shining or the wind blowing for your emission-free electricity.
  • The use of geothermal heat dates back thousands of years to Ancient Greeks and Romans, who tapped hot springs to heat their buildings, spas and bath houses.


How Does It Work?

  • In dry steam plants, steam is withdrawn directly from a subsurface, and used to run the turbines that power a generator.
  • In flash plants, high-pressure and high-temperature geothermal fluids separate into steam, which is delivered to a turbine that powers a generator and the resulting liquid is injected back into the reservoir. This is the most common type of generation
  • In binary plants, the water or steam from the geothermal reservoir never comes in contact with the turbine and generator units. Geothermal fluilds pass through a heat exchanger, where the heat generated causes a secondary fluid to vaporize, driving turbines and generators.


Why Build Geothermal?

  • The Only Baseload Renewable. Since the Earth’s heat is constant, geothermal is the only renewable power sources than can man can completely control. Plant operators can run plants in a baseload or flexible mode depending on how the plant is engineered.
  • Decades of Clean Power. Some fields in California have generated power for over 50 years. There are fields in Italy that have generated power for over a century.
  • High Capacity Factor. According to the Energy Information Administration, geothermal energy has one of the highest capacity factor of any renewable around between 70-75%. Some plants can operate up to 95% of the time coming offline for brief periods of maintenance.
  • Small Footprint. Geothermal has among the smallest surface land footprint per kilowatt of any power generation technology. Geothermal plants are often the size of only a few small buildings or can be designed to blend into a landscape so a passerby wouldn’t even know it’s there.
  • Repurposing the Old. As low oil prices become the new norm, many oil and gas workers are finding themselves without jobs. The good news, geothermal power uses many of the same skill sets as the oil and gas industry, but for clean energy instead.