Geothermal energy is the use of the renewable energy found in the earth’s core. This energy is generated from the origination of the earth’s core, the shifting of tectonic plates, and the radioactive decay of the planet’s minerals and elements. Geothermal energy is used worldwide and is constantly changing.
Hot springs, which have been used since Paleolithic times, occur when there is a fissure through the earth connecting to the inner core. Water seeps into this area, and is warmed all the way to the surface. The oldest known spa is a stone pool on Lisan Mountain built in the Qin Dynasty in the third century BCE. In the first century CE, hot springs were used to feed into public baths as well as for under-floor heating by the Romans.
In 1892, a district heating system was created in Boise, Idaho. It was powered by geothermal energy, and the technology quickly spread across the nation. Geothermal wells began heating greenhouses, and geysers quickly began being used as well. In 1930, geothermal energy was first used to heat structures in the US. New Zealand quickly followed suit, using geothermal heating within structures.
At this point, the decades-old heat pump started being used again to draw geothermal energy. The heat pump was used commercially for the first time in the 1940s. It was used to heat the Commonwealth Building in Portland, Oregon, and was quickly followed by the first residential heat pump. In 1973, during the Oil Crisis, the technology became even more popular. New Zealand once again began using more and more geothermal energy in lieu of oil and is currently one of the largest users of geothermal energy.
Currently, over a million geothermal heat pumps are used worldwide. Each year, about 80,000 units are installed in the United States and 27,000 in Sweden.
Geothermal energy is considered environmentally friendly, however, geothermal energy does have the tendency to release greenhouse gases that are trapped beneath the earth’s surface. This release, however, is much smaller than the amounts released by the use of conventional fossil fuels, so use of geothermal energy reduces the overall impact on the environment.
Many geothermal plants have procedures to recapture their carbon emissions, and it has also been theorized that any fluids that come to the surface through geothermal harvesting can be injected back into the earth.
While the energy released from the earth does carry carbon dioxide, hydrogen sulfide, and other mixtures of gases with them, geothermal energy is still low on the scale of pollutants. Many geothermal plants are equipped with emissions-controlling systems, which can reduce emission intensity as well as exhaust from the various gases.
Geothermal energy has been harnessed throughout history. It has a low environmental impact relative to fossil fuels and has the potential to play an important part in meeting our expanding global energy needs. Now is the time to expand the technology needed to reduce the environmental side effects of geothermal energy and fully exploit this abundant and renewable energy source.