Geothermal energy is poised for a big breakout

“The main problem facing renewable energy is that the biggest sources, wind and solar, are variable. Whereas fossil fuel power plants that run on coal and gas are “dispatchable” — they can be turned on and off on demand — wind and solar come and go with, well, the wind and sun.

Building an electricity system around wind and solar thus means filling in the gaps, finding sources, technologies, and practices that can jump in when wind and solar fall short (say, at night). And the electricity system needs to be extremely secure and robust, because decarbonizing means electrifying everything, moving transportation and heat over to electricity, which will substantially raise total electricity demand.

The big disputes in the clean energy world thus tend to be about how far wind, solar, and batteries can get on their own — 50 percent of total power demand? 80 percent? 100?) and what sources should be used to supplement them. (See this much-cited 2018 paper in the journal Joule on the need for “firm, low-carbon resources.”)

The answer currently favored by renewable energy advocates is more energy storage, but at least for now, storage remains far too expensive and limited to do the full job. The other top possibilities for “firming” electricity supply — nuclear power or fossil power with carbon capture and sequestration — have their own issues and passionate constituencies for and against.

Geothermal power, if it can be made to reliably and economically work in hotter, drier, and deeper rock, is a perfect complement to wind and solar. It is renewable and inexhaustible. It can run as baseload power around the clock, including at night, or “load follow” to complement renewables’ fluctuations. It is available almost everywhere in the world, a reliable source of domestic energy and jobs that, because it is largely underground, is resilient to most weather (and human) disasters. It can operate without pollution or greenhouse gases. The same source that makes the electricity can also be used to fuel district heating systems that decarbonize the building sector.

It checks all the boxes.”

“Tapping into it, though, turns out to be pretty tricky.”