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This article was originally published by our sister site, Freethink, and is a part of The Future Explored, a weekly guide to technologies that change the world. You can receive stories like this straight to your inbox every Thursday morning by subscribing here.

Geothermal energy may finally be about to make its big breakthrough. The often overlooked energy option has seen a surge in demand, investment and new technologies over the past year.

Why it matters

As concerns about climate change grow, we search for ways to decarbonize, and renewable energy sources, such as wind and solar, are all the rage. Indeed, in 2019, US energy consumption from renewable energies exceeded that of coal for the first time since 1885.

Geothermal energy could make clean energy accessible to everyone.

There’s just one tiny problem with solar and wind – they only work when the sun is up or the wind is blowing. So if you are completely dependent on solar energy to generate electricity for your home, you are going to stumble in the dark at night.

That is why we need other sources of energy which can be useful for solar and wind.

Battery storage is one proposed solution. Another solution could be geothermal energy and, if proven to work reliably, it could be a cheap, reliable source of renewable energy that can make clean energy accessible. to all.

Tap, tap, tap

4000 miles below you – the very center of the Earth – is an incredibly hot place… hotter than the surface of the sun. This heat drifts upwards so that even the earth’s crust is hot – as Vox reports, a few miles below the ground you are standing on, there is enough energy to “power all of human civilization for generations. future”.

Geothermal energy, as the name suggests, involves harnessing this power. The concept is nothing new; we’ve actually been using geothermal energy for centuries, tapping into geysers and hot springs for bathing, cooking, etc.

But to produce electricity, we have to go further.

Just digging a few miles below the surface can provide enough energy to generate electricity. In fact, the first commercial geothermal power plant opened in 1960 in California, and there are 64 in operation today. These plants are located in areas with pressurized hot water, such as a hot spring. Then wells are drilled. As the hot water rises through the well, the heat is extracted… and voila, you have sustainable electricity. The cooled water is then returned to the ground to be reheated.

That’s fine – the problem is, doing it this way is quite location dependent. It works best in places like California or Iceland, where there is a lot of moving tectonic plates or volcanic activity to create these reservoirs.

But what about the rest of us?

Deeper in the oven

Conventional geothermal energy depends on natural reservoirs because it is the simplest. But the energy of the Earth is everywhere, including in dry deserts. The higher-level form of geothermal energy (called enhanced geothermal systems or EGSs) involves drilling into dry rock and creating man-made reservoirs by injecting pressurized water into the well, which fractures the rocks that cause it. surround. The water passes through the hot fractured rock and is collected and sucked through another well on the side of the fractured zone.

In theory, these artificial underground ovens could be made anywhere in the world.

Although EGS factories do exist (the first experiment dates back to 1974), due to huge expenses and rudimentary techniques, they did not show much promise – until recently. Thanks to better technology and increased funding, several efficient EGS reservoirs can now produce electricity at prices “close to commercial prices,” according to Quartz.

But as we drill deeper into drier land, the technical hurdles get bigger.

luggage

In order to move from conventional location-dependent geothermal energy to EGS, some public support is needed. This can be tricky because technically EGS is “fracking” – throwing liquid into the ground in order to fracture a rock. And hydraulic fracturing has a certain baggage when it comes to public opinion – in fact, in some areas it is banned altogether.

But as Vox’s David Roberts points out, EGS hydraulic fracturing is safer than gas hydraulic fracturing – the fluids used here pose no risk of contaminating water.

Yet this remains a risky political question. But without public support, experts fear that geothermal energy will remain a neglected source of energy, limited to states with natural reservoirs and no fracking ban.

The result

If the technology continues to advance and public support is won, geothermal energy could be a game-changer – we could technically harness this energy anywhere. The DOE estimates that geothermal could provide about 5,157 gigawatts of electricity, or about five times the power generating capacity in the United States, enough to support us for years.

Or, if geothermal energy were used for direct heating, the DOE writes that it would be “theoretically enough to heat every American home and commercial building for at least 8,500 years.”


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