Stanford University-led research on enhanced geothermal systems (EGS) suggests these technologies could elevate geothermal energy’s role in global power supply, improving cost-effectiveness and reliability.
Traditionally, geothermal energy has been heavily dependent on favorable geographical conditions, such as hot, permeable rock formations and ample underground fluid reserves. This made geothermal exploration limited to volcanically active regions, including Japan, New Zealand and parts of the western United States. However, new advancements, originally developed for oilfields, hold the promise of unleashing geothermal energy potential across a broader range of locations.
“There is a lot of excitement about enhanced geothermal energy,” Roland Horne, a professor of energy science and engineering at Stanford University’s Doerr School of Sustainability, said in a news release.
Earlier this month, Horne convened more than 450 engineers, scientists and managers from 28 countries during the 50th Stanford Geothermal Workshop to discuss the latest developments in geothermal technology.
Enhanced Geothermal Systems (EGS) utilize advanced techniques like hydraulic fracturing and horizontal drilling to access deep underground heat reservoirs, making it feasible to generate geothermal energy in regions previously deemed unsuitable. These techniques, borrowed and adapted from the oil and gas industry, have been vital in reducing drilling times and costs.
“Drilling faster makes an enormous difference to the whole economics of EGS,” added Horne, who co-authored a review paper published in Nature Reviews Clean Technology with a small team he gathered together.
Based in part on model-based research led by Stanford doctoral student Mohammad Aljubran, Horne and his co-authors estimate that faster drilling rates could make EGS competitive with current average electricity prices in the United States by 2027, reaching approximately $80 per megawatt-hour.
This could be transformative, particularly for states like California, which already garner about 5% of their electricity from geothermal sources.
The review paper suggests that California’s geothermal capacity could increase tenfold by 2045, reaching 40 gigawatts. This increase could offer a stable, reliable foundation for a power grid heavily reliant on intermittent renewable resources like wind and solar.
“With EGS, we can meet the load,” Horne added.
Enhanced geothermal could thus provide the stable, baseload power essential for transitioning to a fully renewable energy grid.
However, one challenge EGS faces is mitigating the risk of induced seismicity, or earthquakes triggered by drilling activities. Strategies to manage this risk include avoiding drilling in seismically active areas, monitoring seismicity with a traffic-light protocol and employing a “drip-drip-drip” approach to prevent large-scale fluid injections.
“A drip-drip-drip instead of a fire hose approach can significantly reduce the risk and size of induced seismicity,” Horne added.
The potential impact of these EGS advancements extends globally, promising a cleaner, more reliable energy source.
“EGS could be a game changer for green energy production not just in California but across the U.S. and worldwide,” concluded Horne. “Safely harnessing Earth’s internal heat could substantially contribute to powering our future.”
Horne, also a senior fellow at Stanford’s Precourt Institute for Energy, collaborates with several EGS-focused companies, including Utah FORGE and Fervo Energy. His colleagues and co-authors of the upcoming review paper believe that ongoing research and development investments could accelerate EGS implementation, setting a new standard for renewable energy technology.