Geothermal energy may finally be nearing its big breakthrough. Or not. In 2021, this often overlooked energy option has seen a sharp increase in demand, investment and new technologies.
As concerns about climate change grow, we seek ways to decarbonise. It goes without saying that renewable energy sources, such as wind and solar, are all the rage. In July 2020, renewables for the first time they produced more energy of fossil sources.
Geothermal energy could make clean energy accessible to all.
There's just one very small problem with solar and wind: until permanent storage solutions, they only work when the sun is shining or the wind is blowing. So, if you are completely dependent on solar to generate electricity for your home, you will stumble in the dark at night.
This is why we need other energy sources that can complement the solar and wind power supply.
If geothermal energy proves reliable, it could be a cheap, reliable source of renewable energy that could make clean energy accessible to all.
Dig, dig, dig
About 6500 kilometers (4.000 miles) below us, the center of the Earth is an incredibly hot place. Hotter than the surface of the sun. This heat moves upwards and ends up heating the earth's crust as well. In general, a few kilometers under our feet there is enough energy to power all human civilization for generations to come.
It's geothermal energy. And we've been using it for centuries, tapping into geysers and hot springs for bathing, cooking and more. Of course, to produce electricity, you have to dig (a little) more. But digging a few kilometers below the surface is enough to provide sufficient energy.
The first commercial geothermal energy plant is Italian, you knew that. And it is more than 200 years old. It was opened in 1818 in a hamlet of Pisa, Tuscany, since then renamed Larderello. Why? Because the entrepreneur Francesco Giacomo Larderel, of French origins, had the idea of using geothermal energy. Since then we have used many areas with pressurized hot water. We drill wells. We extract the heat as the hot water rises through the well… and voilà, that's sustainable electricity.
A matter of position, but ...
That's all great - the problem is that the results are quite location dependent. This is why geothermal energy works best in places like California or Iceland. There are many moving tectonic plates or volcanic activity there that creates these reservoirs.
Be careful, though. Conventional geothermal depends on natural reservoirs because it is the simplest. But Earth's energy is everywhere, even in arid deserts. The next step in geothermal energy is called the advanced geothermal system, or EGS.
What does an advanced geothermal energy system consist of?
It involves drilling into dry rock and creating artificial reservoirs by injecting pressurized water into the well, which fractures the surrounding rocks. The water passes through the hot, fractured rock and is collected and drawn through another well on the side of the fractured zone. In theory, these man-made underground ovens could be made anywhere in the world.
Although EGS implants do exist (the first experiment dates back to 1974) they weren't very successful until recently. Cost matter mainly. But thanks to better technology and increased funding, several successful EGS basins can now generate electricity at very low prices.
A joint effort is needed
Moving from conventional geothermal to EGS requires a little support from the public. This can be tricky because EGS is technically “fracking.” Liquid is “shot” into the ground to fracture a rock. And fracking carries some weight when it comes to public opinion. It is no coincidence that fracking is completely banned in some areas.
Of course, experts assure that EGS fracking is safer than "traditional" fracking, which uses gas: the fluids used for EGS geothermal energy do not risk contaminating the water in any way.
However, it remains a risky political issue. And without public support, experts worry that geothermal energy will remain a neglected energy source, limited to states that have nature reserves or no ban on fracking.
Geothermal energy: the sliding doors of recent years
If technology continues to advance and public support is gained, geothermal energy will have its tipping point: we could technically harness this energy anywhere. If we used it for direct heat, it would be enough to heat every home and commercial building in Europe for at least 8.000 years.
