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Could next-gen geothermal provide the clean firm power we’ve been looking for?

Google just announced an investment in the energy source that hasn’t gotten a lot of airtime recently. 

Earth core structure.

The earth’s core is as hot as the surface of the sun, leading some geothermal enthusiasts to whimsically call the resource “the sun beneath our feet.” 

In its quest to power operations by clean energy all day every day by 2030, Google just announced an investment in an energy source that hasn’t gotten a lot of airtime recently: geothermal. 

One of the biggest challenges to decarbonize the power sector is finding "firm" renewable energy — that is, energy that is available where and when it’s needed, regardless of external factors. Wind and solar, while cheap and plentiful, are variable. They don’t work when the sun isn't shining or when the wind isn’t blowing. 

Energy wonks are modeling out different technologies to fill the gap, such as energy storage and green hydrogen. Less talked about is the potential of geothermal: a firm, abundant energy source that has had trouble breaking out of its niche status for decades. 

Google hopes to change that. In a partnership with clean-energy startup Fervo, Google said it is investing in developing a "next-generation geothermal power project, which will provide an ‘always-on’ carbon-free resource."

What is geothermal? 

Fun fact: The earth’s core is as hot as the surface of the sun, leading some geothermal enthusiasts to whimsically call the resource "the sun beneath our feet."

The main stumbling block for the energy source: money. It’s expensive to drill deep holes, especially when it needs to go through igneous and metamorphic rocks.

Geothermal energy taps into the heat by drilling deep wells, which can be 1 to 2 miles deep. That heat can be used in a variety of technologies to offer climate control in buildings or to drive turbines to generate electricity. 

Its capacity is impressive. ARPA-E says just 0.1 percent of "the heat content of Earth could supply humanity’s total energy needs for 2 million years." All we need to do is tap into it. Yet it only accounts for 0.4 percent of electricity generation in the U.S. 

What gives?

The main stumbling block: money. It’s expensive to drill deep holes, especially when it needs to go through igneous and metamorphic rocks. (Oil and gas are mostly from sedimentary rocks, which are softer.) The cost for a new geothermal plant costs about $2.5 million per megawatt installed, compared to around $820,000 per MW of solar

Also impacting deployment is location. There are regions where the heat is closer to the Earth’s crust, making it easier to tap into. Think Yellowstone Park, natural hot springs, or Iceland, which famously uses geothermal energy to heat the sidewalks and streets in some cities to keep the ice away. 

If we’re able to scale geothermal affordably, it could offer a source of the elusive dispatchable renewable energy — meaning it could fill in the gaps for other, intermittent renewable energy sources. 

What makes Google’s geothermal project different?

Google boosts a new approach to capture the earth’s energy through "fiber-optic sensing, and analytics techniques." Using AI technology from Fervo, the vision is to gather real-time data on temperature and performance, which would allow control of the energy flow.

While Google’s project is relatively small — just 5 MW, which would serve its data center in Nevada — the speed of deployment is notable. It is expected to be up and running next year. 

In part, this speed is made possible by advancements in drilling developed by the shale industry. Not only could this knowledge spur forward geothermal development, it also could provide new employment opportunities for those in the natural gas sector, which has been hemorrhaging jobs

If Google figures out how to harness geothermal for round-the-clock clean energy, then the company will be doing more than powering its data centers. It could crack the code for a firm renewable energy resource that every community, corporation and country will need to reach its 100 percent clean energy goals. If anyone can, my bets are on Google. It has the margins, the brainpower and the will.

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