Google turns to geothermal energy to power its carbon-free moonshot

Google's green goals are extremely ambitious. The search giant aims to operate its entire business on carbon-free energy, 24 hours a day, 7 days a week, by 2030. At Google I/O 2021, the moonshot has received a welcome boost with the announcement it will turn to "next-generation" geothermal energy to power data centers and infrastructure throughout Nevada. 

"We are the first corporate to sign an agreement to develop next-generation geothermal," Kate Brandt, Google's sustainability officer, told CNET in a call prior to I/O.

The agreement is with Fervo Energy, a clean energy startup aiming to "unlock" the potential of geothermal resources. Starting next year, Fervo will work with Google to begin to add geothermal energy to Nevada's grid. It would complement existing renewable energy sources in the area, pushing Google towards its 24/7 goals.

Geothermal power plants use heat from the Earth as an energy source. Deep below the planet's surface, radioactive material is decaying and magma is heating up water, which provides an almost limitless supply of energy, if you can get to it. 

"It is a phenomenally great source of energy," says Graham Heinson, a geophysicist at the University of Adelaide. "And there is huge amounts of trapped heat in the Earth that could power enormous parts of the world."

Humans have been harnessing geothermal energy for millennia, wherever the heat travels up to the surface, like in a hot spring. The water at the surface is warm (or scalding!) because it was heated by the Earth during the Old Stone Age, more than 12,000 years ago.

In modern times, the heat can be harnessed by drilling wells into the ground and extracting hot water present there. This hot water (and steam) get pumped to the surface where they power a turbine and generate clean electricity. In Iceland, for instance, this "traditional" geothermal power is responsible for around two-thirds of the country's primary energy use.

And geothermal has one significant advantage over other renewable energy sources. It's always available.

"Wind and solar have been mainstays of our strategy, but geothermal is a great source of energy because it's on demand," noted Brandt. 

The wind doesn't always blow, the sun doesn't always shine, and that can be a problem, especially for a company like Google, which needs data centers operating on reliable energy at all hours of the day. Brandt notes Google needs to find ways to power its operations when those sources aren't enough. Fortunately, you can count on the subterranean Earth to always be warm, provided you're digging in the right place.

Geothermal isn't without its own problems, though. Finding reservoirs of water deep underground can be difficult, isn't economically feasible in some locations and the initial cost and risk of building plants can be high. This has stalled progress on geothermal. 

"Historically, there hasn't been a demand for geothermal power due to its high risk-weighted cost," said Graeme Beardsmore, an Earth scientist at the University of Melbourne, Australia. But with the rapid imperative to decarbonize, Beardsmore notes, geothermal is seeing a rapid increase in interest. 

"The risk-reward equation is changing because the value of low-emissions power is increasing," he said.

A new twist on geothermal energy

Fervo, which received funding from the Bill Gates-backed Breakthrough Energy fund in 2018, has been trying to overcome some of the challenges of older geothermal tech. The startup's idea is to build an Enhanced Geothermal System, almost as if they're creating their own reservoir to draw from deep in the Earth -- except, not quite. 

The EGS pipes water down into the Earth and harvests the heated fluid after it passes through the rock, well below the surface. That helps mitigate the task of finding reservoirs closer to the surface.

With Google on board, it's a two-heads-are-better-than-one approach. Google's expertise in computing and data will help improve Fervo's geothermal energy production and facilitate rapid responses to electricity demand. "We're combining our novel AI with some drilling techniques and fiber-optic sensing," Brandt said.

The goal on the consumer side is a simple one: all Google products run on carbon-free energy.

"Every email you send through Gmail, every question that you ask Google search, every YouTube video you watch, would be supplied with clean energy every hour of every day," said Brandt. 

Achieving that goal will be challenging, she concedes, noting many places still operate with "dirty energy," using fossil fuels to power the grid. That's certainly true where I am based, in Sydney, Australia, where coal dominates the energy mix. Unless there are changes in policy or procurement in my region, the products I use to access Google's services won't be running on clean energy. "That's why this is going to be hard," Brandt said.

It's not the first time Google has invested in EGS, with dollars flowing to develop different technologies back in 2008. But the strategy is a big stamp of approval for the technology moving forward. The United States already generates the most energy from geothermal power plants in the world, but it still only accounts for less than half a percent of electricity generated in the country. Beardsmore says it's unlikely Google's involvement will be "transformational" but may help spur growth in the sector.

"It's always an exciting development when another EGS project begins, because EGS is really the only way that geothermal will be able to grow exponentially as an industry," he said.