Startup Fervo Energy just made hot-rock history. The company says it is the first to demonstrate that an enhanced geothermal system can reliably produce electricity. Fervo’s full-scale commercial pilot, Project Red in northern Nevada, passed its production test phase, a 30-day well test standard for geothermal energy resources. The company reported that its system achieved a flow rate of 63 litres per second at high temperatures, conditions that would generate 3,5 megawatts of electricity production, enough energy to power roughly 2500 homes. According to the company, these results set a record for flow and power output for an enhanced geothermal system. Unlike conventional geothermal resources, enhanced geothermal technologies create new fissures to coax energy out of hot rocks. “The takeaway is next-generation geothermal is here today,” said Gabe Malek, Fervo’s chief of staff. “It’s ready to deploy, it’s ready to scale. It’s now a question of how fast we can do it, and at what magnitude.”
The milestone marks an inflection point for geothermal as a clean energy resource. It proves the technical feasibility of an enhanced geothermal system, The next step in unlocking enhanced geothermal’s full potential is to drive down the cost of the technology through more deployments. One key to that effort will be more offtakers signing power purchase agreements (PPAs), a model that has been crucial for scaling solar and wind energy.
The promise of enhanced geothermal
Enhanced geothermal systems have long been a clean energy dream. Traditional geothermal taps into naturally occurring fissures underground, heating water that runs a turbine. Enhanced geothermal systems are designed to create fissures in underground rock, allowing geothermal wells in more locations.
This means its energy potential is much greater than conventional geothermal. According to the National Renewable Energy Lab, the resource potential of enhanced geothermal is more than 230 gigawatts in the United States alone when drilling to 4000 metres or less − the depth oil and gas drills can access with existing equipment.
What’s more, geothermal is not weather-dependent. That means it has the potential to provide clean, firm energy that can complement wind, solar and batteries to fully decarbonise electricity. The ability to operate fully from clean energy, sometimes known as 24/7 carbon free energy (CFE), is increasingly a goal of the public and private sectors. In fact, Google’s own quest to reach 24/7 CFE inspired the tech giant to partner with Fervo in Project Red. Recognising its massive decarbonisation and economic promise, the Department of Energy issued an enhanced geothermal Earthshot initiative last year, with funds dedicated to driving down the cost of enhanced geothermal technologies by 90% by 2035.
The geothermal learning curve
Key to unlocking the potential of enhanced geothermal, and crucial for Fervo’s milestone, are hydraulic fracturing (fracking) technologies developed by the oil and gas industry to extract natural gas. Fervo uses the same technology to drill lateral wells, and then drill horizontally in geothermal reservoirs to access more heat resources.
Fervo’s breakthrough is a design that drills multiple horizontal wells from a single location. The trick is that every horizontal well is more or less the same, meaning Fervo can take that one technique and copy and paste over and over again, standardising the process and opening up more hot rock resources for each set of lateral wells. This approach can make geothermal simple and repeatable. Instead of each new project requiring a unique, individual design, each new deployment can become more efficient. This will help drive down the cost of deployments.
“One thing that’s plagued geothermal traditionally is that each project is bespoke to a certain degree,” Malek said. “Since we’re able to drill pairs of horizontal wells, the process can become repeatable. And we know that with those economies of scale, costs go down.”
Time to ink your geothermal PPA
Organisations with 24/7 carbon free energy and decarbonisation commitments have an opportunity to be early adopters of these technologies. Some have already taken the plunge with Fervo. They include Google and East Bay Community Energy, a community choice aggregator in California. According to Fervo, demand for its technology has been high. The company says its PPA card is full through 2028, and that was before the successful test phase. Fervo’s milestone makes its proposition even rosier. Offtakers interested in geothermal can help scale the resource without the same technological risk prior to this proof point. “It allows us to reach offtakers that are more risk averse “ Malek said. “Certainly, there are improvements that we will continue to make, but they are no longer taking a gamble on the core underlying technology.”
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