As part of the fight against climate change, it’s essential to recognize the various forms of clean energy we have available, and how we can use them to benefit our planet. Turning to sources of renewable energy whenever possible will reduce the need for fossil fuels, which perpetuate the creation of greenhouse gasses and resource consumption. So far, popular sources of renewable energy include wind, solar, and hydroelectric. One renewable resource, geothermal energy, has yet to be explored to the fullest, but it holds great potential and can also be found right under our feet.
As part of the fight against climate change, it’s essential to recognize the various forms of clean energy we have available, and how we can use them to benefit our planet. Turning to sources of renewable energy whenever possible will reduce the need for fossil fuels, which perpetuate the creation of greenhouse gasses and resource consumption. So far, popular sources of renewable energy include wind, solar, and hydroelectric. One renewable resource, geothermal energy, has yet to be explored to the fullest, but it holds great potential and can also be found right under our feet.
Geothermal energy is a type of renewable resource naturally created by the Earth’s core. To further understand how this type of energy is formed, we must first examine how our planet is structured.
Have you ever seen the inside of a jawbreaker? If you break one apart, you’ll find dozens of colorful, overlapping layers inside. Our planet is quite similar to a jawbreaker, though the design is a bit more complex. We live on the surface of the Earth, which is also called the ‘crust.’ Below the crust are several layers of rock, minerals, and molten magma that make up the ‘mantle.’ All of these layers are constantly being heated by our planet’s central ‘core,’ which can reach temperatures over 90032° F. National Geographic explains here that the majority of the core’s heat is generated by friction and Earth’s gravity, combined with the decay of radioactive isotopes.
This geothermal energy radiates up the Earth's mantle and heats reservoirs of water beneath the crust. Hot steam or water can then escape through cracks in the Earth's surface, which then makes them accessible to harness. Geysers and hot springs are both examples of how water is naturally heated by the earth’s energy.
Once this type of energy is created, how do we get to it? There are several forms of technology that allow us to use geothermal energy, the majority of them using steam and water as essential tools for extracting.
Geothermal energy can be used for a variety of purposes, such as providing heat. To gather heat from geothermal energy, buildings can be heated directly using special devices: a heat exchanger and heat pump. These devices work together to convert cool water into warm water. The heat exchanger is a loop of piping placed deep underground where the temperature remains at 54°F. The exchanger connects to the heat pump to help circulate water throughout the loop. As cold water is pumped into the ground, it’s warmed up by the Earth’s temperature and sent into the heat pump. As a result, heat is generated and can be spread throughout a home or building via a vent system.
To generate electricity, geothermal energy first has to be converted from heat into steam. This can be done through several different technologies found in geothermal power plants: Dry steam, flash steam, and binary cycle. Capturing geothermal energy with these methods often requires drilling holes deeper below Earth's surface to release steam.
Dry steam geothermal technology has been around the longest with one of its earliest uses dating back to the 18th century in Tuscany, Italy.
In a dry steam power plant, steam is gathered straight from a geothermal source. It travels through a pipe and ultimately spins a set of turbines to generate electricity.
Flash steam power plants use water to harvest geothermal energy. This type of technology pumps hot water from underground to the surface. A large tank, called a flash tank, rapidly cools the water to form steam. Electricity is generated when the steam enters another chamber and spins a set of turbines.
Binary cycle power plants use technology similar to flash steam, but with a slight variation. Hot water is pulled from the ground and into a tank, heating a separate liquid that turns into steam. A heat exchanger is used to make this conversion.
Several factors make geothermal energy a reliable source of sustainable energy. The main advantage of using geothermal energy is that, compared to fossil fuels, it's a renewable resource. Earth is capable of producing heat from its core for billions of years, which means this resource cannot be depleted. Another advantage, because this type of energy comes from underground, it's available to us throughout the year regardless of season or weather conditions.
This report further notes the benefits of geothermal energy in that power plant technology can provide us with a generous amount of electricity and at low-costs. It’s estimated that the heat produced by our planet holds 50,000 times more energy than the world’s gas and oil resources. Geothermal energy also uses minimal amounts of resources. Power plants do not take up much space, and depending on the technology being used, geothermal energy can be extracted from many parts of the world.
Geothermal energy is considered to be an environmentally clean resource. Although geothermal energy plants need water to function, the majority of the wastewater created in power plants can be reused throughout the system. Once a cycle is complete, the water used to create steam and generate electricity is pumped back underground instead of being disposed of. Because of this, little to no greenhouse gasses are emitted when using geothermal energy.
The International Renewable Energy Agency provides statistics on the amount of power geothermal energy has generated over the past several years. This data shows the global installed capacity of geothermal energy has increased from nearly 10,000 MW of electricity in 2010 to 14,050 MW in 2018.
NS Energy breaks down (https://www.nsenergybusiness.com/features/top-geothermal-power-producing-countries/) several of the world’s leaders in harnessing geothermal energy use. The United States is the current leader of geothermal energy, with its installed capacity being at 3,639MW. Most of this energy is harvested from Western states, from facilities like the Geyser’s Geothermal Field in Clear Lake, California. Indonesia is next on the list with a capacity of 1,948 MW and is projected to surpass the United States by 2027.
With its wide range of accessibility around the world, and its limited use of natural resources, geothermal energy has the incredible potential to be a clean and sustainable form of energy. If it’s successfully recognized on a global scale, then even greater developments in geothermal technology can be made to improve how we power our planet.