What is geothermal energy? Geothermal energy is heat that comes from beneath the crust, and it is in our best interest to turn this heat into energy. There are currently 3 ways we do this and the first, most common option is surprisingly simple. As water trapped in the crust gets heated, it rises. Eventually, it reaches the surface and gets released from the ground. Due to the pressure differences between the surface and the deep crust, the water turns to hot vapour, causing hot springs. They are an amazing tourist destination and you can find them all around the world! (Think Yellowstone, and Iceland to start!).
So how do we take advantage of this? We use a method called Dry Steam Geothermal. This is when vapour from the ground is routed by a long series of pipes to a turbine which subsequently turns a generator making electricity! This is the most common but sometimes conditions aren’t right for this method.
Another method we use is called Flash Steam geothermal. This is when hot fluid is pumped into a tank at the surface where it then cools and condenses to water vapour, turning a turbine then a generator.
The last method we use is similar to flash steam geothermal but slightly different. It is called Binary Cycle Geothermal and it takes advantage of another liquid’s low boiling point. The hot fluid from underground is pumped into a tank where it heats up a heat-exchange liquid with a lower boiling point. This is then condensed into vapour, turning a turbine and making electricity. This genius way of making electricity is currently used in 26 countries. According to a Geothermal Energy Association (GEA) report, only 6.9% of the global potential has been used which is so exciting! There is so much more potential!
Photographer: Viktor Kiryanov, Geothermal Power Plant at Night
Most geothermal plants are in fact on plate boundaries, especially constructive and destructive ones. A large proportion of these plants can be seen on the coast of Chile, where the Nazca plate is subducting under the South American plate, East Africa, where the continent is breaking apart and many other places including Iceland and New Zealand due to the constructive and destructive plate margins.
So where did geothermal energy come from? Well, the historical record suggests that Paleo-Indians used hot springs for cooking and warmth over 10,000 years ago. Also, in Iceland, it is a common practice to cook bread this way. But when was geothermal energy actually recognised for its economic potential? Its first industrial use was near Pisa, Italy in the late 1700s. Steam from both natural and artificial holes in the ground was used to extract boric acid from the Larderello fields.
In the late 1800s, residents in Boise, Idaho received geothermal heat for their homes. In 1904, Piero Ginori Conti first made electricity from geothermal heat. He was a businessman, who was head of the boric acid extraction project mentioned earlier. The firm he was working for was founded by his wife’s great-grandfather in Larderello. On July 4th, he powered 5 dynamo driven bulbs using geothermal power. At this point, this was his main focus rather than boric acid. He then increased this power production to 20kW in 1905. Eventually, he made this system work so well, in 1916, he was able to distribute 2750kW of electricity to a massive area including Volterra and Pomerance. However, this project was stopped until 1921 due to the war and social unrest. Ultimately, Benito Mussolini gained power and put a stop to that. Piero Ginori Conti and his family were big supporters of him. However, Italy was not the only place where geothermal energy was being used. In Iceland, there has been recorded use of geothermal sources to cook and bathe in 1907. After World War 2, Orkustofnun (Iceland’s National Energy Authority) began researching using geothermal energy as the country’s primary energy source. At present, Iceland has a 99.96% renewable energy supply and this is used in a variety of ways, including heating homes, making electricity and even making aluminium. Iceland uses a lot of energy despite its smaller size. Many countries are looking to Iceland for help as industry thought leaders.
This is only the beginning of the evolution of geothermal. Stay tuned for more.
For more Geothermal Facts and Stat blog posts, click here.
Arjun Bahra is a teenager and an aspiring seismologist/geophysicist with a keen interest in math, science and geography. Arjun enjoys the way that these subjects link together in the field of seismology and the field of geothermal energy. His Instagram account is @everything_earthquakes and can be contacted by email: [email protected]