Big Oil majors have been scrambling to make the most ambitious climate commitments in the industry, planning a pivot to clean energy, talking about net-zero emission bills, solar, and wind. However, there is another clean energy source that has remained out of the spotlight–one that may eventually rise to prominence: geothermal.
Geothermal energy is, simply put, the heat from the Earth’s mantle brought to the surface to use for heating and, more importantly, electricity generation. Iceland is the usual example of successfully harnessing geothermal energy. Iceland, however, is not the only place where geothermal can be tapped. In fact, it’s everywhere. You just need to know exactly where and how to drill for it.
Yes, the keyword here is drilling and extraction: the same thing oil and gas companies do. It should come as no wonder then, that a number of oil and gas industry veterans have decided to go down the clean energy road with geothermal projects. And according to them, geothermal is the future of the energy industry, along with solar and wind.
How does this geothermal energy extraction work? The Earth’s core and the mantle are superhot, which is why the deeper you drill for oil and gas, the hotter the rock. Drill deep enough, and you would reach formations where the temperature is 200 degrees Celsius (392 F) and above. This is where geothermal’s potential begins. The planet produces heat constantly, which means it is a much more reliable source of energy than solar and wind with their intermittency problems. And this heat is clean, unlike oil and gas. It sounds almost too good to be true.
There are two principal ways of extracting heat from the ground. One is via enhanced geothermal systems (EGS), and the other is closed-loop extraction or advanced geothermal systems (AGS).
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EGS is in a way similar to gravity-assisted oil extraction in the oil sands, involving drilling first vertically and then horizontally, and fracking the formation to release the heat, which heats the water injected into the well and then brings it to the surface.
AES, or closed-loop systems, are essentially radiators drilled into the ground, as the executive director of the Geothermal Entrepreneurship Organization at UT at Austin, Jamie Beard, explains here. You drill deep enough to tap some high heat, flush a special fluid inside, it heats up, travels up, and powers the turbines of a power plant. This is the biggest promise of geothermal: clean electricity generation.
Clearly, extracting heat is quite similar to extracting oil and gas, which is why industry experts are the most likely proponents of this alternative energy. Two of them, vets from Weatherford and Shell, have even designed a hybrid geothermal extraction system that combines fracking and closed-loop drilling to extract geothermal energy. In that system, Lance Cook and Lev Ring, co-founders of startup Sage Geosystems, do away with the need to drill superdeep vertical wells. Thanks to fracking, you could drill a shallower well and…