There are some energy sources that are “free” here on Earth, namely wind, solar, hydroelectric and geothermal. Humans have been harnessing water and wind for millennia, and we’re getting pretty good at harnessing the power of the sun. But with geothermal, we’re not yet cleverly harnessing the heat generated deep inside the planet.
Most commercial-scale geothermal installations are found in geological hotspots such as Northern California and Iceland. On a smaller scale, many homeowners have dug shallow wells or buried loops in their backyards for heating and cooling. But to truly unlock geothermal potential around the world, and do so profitably, we’ll need new ways to dig deep and boost the Earth’s heat.
As the world teeters through an energy transition, many energy geeks talk at length about deployable baseload power. This is a lot of jargon. “Dispatchable” means that grid operators can request a plant to produce power with minimal notice and it will deliver. And “base load” means power that can always be on, regardless of the weather. Renewable energies such as solar and wind are not, per se, commodity energy. It’s a different story if they’re paired with batteries to store energy for use when the wind is calm or the sun isn’t shining. The combination of renewables and batteries is happening with increasing frequency, but batteries remain expensive and why not have more options beyond that?
To truly unlock geothermal potential around the world, and do so profitably, we’ll need new ways to drill deep and boost the Earth’s heat.
Geothermal is often touted as a carbon-free source of dispatchable baseload energy, which is why energy geeks are getting hooked on it. In a geothermal plant, a working fluid, often water, is injected into the ground, where it is heated before being pulled up again to flow through a heat exchanger or drive a turbine.
The heat source is almost unlimited. The Earth continuously generates about 44 terawatts of heat, about half of which comes from natural radioactivity. That’s about 385,000 terawatt-hours of energy released each year, far more than global energy use, which was just under 23,000 terawatt-hours in 2019. If we could tap into a fraction of the Earth’s heat, well, we’d have a lot of energy at our disposal.
The potential of geothermal coincides with the looming decline of the fossil fuel industry, causing many engineers to rethink their careers. It so happens that many of the drilling techniques being developed for the oil and gas industry dovetail perfectly with what is needed to bring geothermal mainstream.
There are a number of startups attempting to transform geothermal from a niche power source to one that could be widely used. Here are five that I’ve seen.
If there was an award for sexiest geothermal technology, Quaise Energy would likely be the winner.
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