Renewable energy sources are becoming more and more important to our society each and every day. The reckless use of nonrenewable fossil fuels over the last few centuries has had a devastating effect on our environment and our health. Furthermore, it will take millions of years for these resources to be replaced, a time-frame so large that it is functionally meaningless for our species. One of the most reliable methods of producing renewable energy that scientists have come up with is geothermal power.
Under the surface of our planet’s crust, there is an enormous amount of thermal energy just waiting to be tapped. The core of the Earth is primarily molten iron and rock, and this melted stone and metal brings heat to every corner of the globe. This heat is leftover from the formation of the planet and the radioactive decay of elements that were present during that time as well. By finding ways to channel this energy to the surface, scientists are looking to gain access to an environmentally clean and sustainable source of enormous amounts of power.
Technically, people have been making good use of geothermal energy for thousands of years, most likely since paleolithic times. Throughout the world, there are naturally occurring hot springs, used by a variety of different cultures and ethnicities. These springs are heated by geothermal energy. In the first century, Roman conquerors used hot springs in order to fill the baths and underfloor heating. In the fourteenth century, France built the world’s first geothermal district heating system.
Today, the United States produces about 3,500 megawatts of electricity through the use of geothermal power plants, about thirty percent of the total geothermal energy produced globally. There are three different ways to approach the harnessing of this energy beneath our feet: liquid dominated plants, thermal energy plants, and enhanced geothermal plants.
Liquid dominated plants are commonly located at areas with high temperatures, those at least at least 392 degrees Fahrenheit. Often they can be found in the direct vicinity of volcanoes. As the water turns to steam, that steam is harnessed for the production of electricity. While the water is circulated back to where it came from, able to be reused.
Thermal energy plants function through the use of heat pumps, primarily used for home and water heating across the world. This method of heating is far more cost effective in most places than converting thermal energy into electrical energy. Directly channeling the thermal energy is also more energy efficient than other methods.
The enhanced geothermal plants are slightly more involved than the other two methods of geothermal energy extraction. It involves directly pumping water into wells at a high pressure in order to expand cracks and faults in the rock, allowing water to be pumped out faster. This method was adapted from techniques used by oil and natural gas companies to extract fossil fuels from the ground.