By Irina Slav
Here’s fun fact: the world’s deepest manmade hole goes 15 kilometers into the ground. They stopped drilling at the 15th kilometer because it got too hot at the bottom of the hole. Welcome to geothermal energy, the reason most religions depict Hell as a place deep underground and the reason why we may succeed in building a clean energy future for the planet without turning it into a disco ball of solar panels.
Geothermal energy is, simply put, heat; heat that is generated from the decay of radioactive elements in the planet’s mantle. The amount of energy this heat translates into is stunning. According to the Union of Concerned Scientists, just 33,000 feet below the Earth’s surface there is 50,000 times more energy than the energy all the oil and gas in the world can produce. This energy can be harnessed and used for heating and power generation.
Of course, from a driller’s perspective, 33,000 feet, which is equal to 10 kilometers, is not exactly a small distance to drill. Yet it is not impossible as those engineers in the ‘80s demonstrated with their 15-km hole. We just need to develop the drilling technology.
The problem with geothermal energy—or rather the obstacle to turning it into a mainstream source of energy—is that not all heat from the Earth’s mantle is equally accessible everywhere in the world. In some places, such as Iceland and New Zealand, the heat is closer to the surface, so it is easier—and more importantly cheaper—to tap and use.
In other places, however, the heat is trapped deep underground. This is not really a bad thing: the so-called hot spots of geothermal energy are in places with high tectonic activity, meaning more frequent earthquakes, and in place where the Earth’s crust is thinner.
Yet the great thing about geothermal energy is that it is everywhere, not just in the hot spots. True, the hot spots have the highest temperatures, with some natural geysers reaching 200 degrees Celsius and more. But geothermal energy can also be used at lower temperatures for direct heating purposes. This is what people in Iceland do. Most of the heating needs of the tiny Northern nation are satisfied by its geothermal resources. Others are following the example, too. Just this week a geothermal heating system was switched on in China, promising to cover the heating needs of as many as 35,000 people in the Xi’an Jiaotong University’s innovation hub. In doing so, geothermal energy will also eliminate the release of 68,000 tons of carbon dioxide annually.
The Chinese geothermal system draws the heat from a depth of just two or three kilometers into the ground, with temperatures reaching between 70 and 120 degrees Celsius. The great thing about modern technology, however, is that we can harness the power of heat from even shallower depths.
This is what a unit of French utility Engie is doing near Paris. It is drilling a 2.3-kilometer hole to tap underground water that sports temperatures of above 70 degrees Celsius. This water will be captured into a pipeline system and used to heat households in the area before being returned to the underground reservoir. The amount of CO2 eliminated was some 25,000 tons annually.
The geothermal trend is certainly catching on. Finland is another country that is considering utilizing the Earth’s natural heat for heating and possibly power generation. It has yet to find out if it has geothermal resources that can be exploited economically but it is working on it.
Germany is tapping into its geothermal potential, too, which is unsurprising given the country’s ambitious carbon neutrality goals. It already has a geothermal heating and power plant in Bavaria and there are plans to boost this capacity considerably before 2040, when Bavaria wants to be completely carbon neutral.
Turkey is yet another case in point. The country has geothermal capacity of over 1.3 GW and plans to raise this to 7 GW by 2025 as energy demand grows and Turkey does not want to stay in the fossil fuel rut, especially since a lot of the oil and gas it uses are imported.
Examples abound. The world seems to be waking up to the potential of geothermal energy and the fact that it does not necessarily need to be prohibitively expensive. The United States is no exception, either.
Earlier this month, the University of Texas announced a geothermal energy initiative dubbed the Geothermal Entrepreneurship Organization that will aim to turn Texas into a national hub for all things geothermal.
This is only fitting. The country’s oil heartland has the relevant expertise, after all. As the leaders of the initiative, Bob Metcalfe and Jamie Beard from the UT’s Cockrell School Innovation Center put it, “Drilling complex, very hot and very deep wells is what the oil and gas industry does best. Existing technologies paired with new innovations aimed at driving down drilling costs can be leveraged to enable drilling for geothermal energy anywhere in the world. Geothermal baseload is doable within a decade.”
Baseload is the magic word. Baseload is the reliable, constant flow of power that a grid needs to be able to do its job. Solar and wind lack it without a solid energy storage facility. Yet geothermal energy flows constantly. It’s all a matter of capturing it and utilizing it for heating and power generation.
It is not without its problems, chief among them the concern of increased seismic activity caused by drilling, which is making investors wary of giving their money to such projects. Another problem are the high upfront costs, but these will naturally fall over time, again thanks to advancements in technology that has made drilling for oil and gas so much cheaper than before.
There is a future for geothermal energy, and it could be a bright one if we decide to pay it the attention it deserves.