Breakthrough in Geothermal: High-Temperature Monitoring Sets New Record
Scientists and industry partners, including Fervo Energy, are developing enhanced geothermal systems (EGS) to harness constant heat from deep underground for affordable, continuous energy production. This innovative approach is crucial for expanding the nation's clean energy portfolio.
EGS reservoirs can generate microseismic events, typically low-magnitude and rarely felt, which help researchers understand rock fracture formation and advance geothermal energy.
Record-Setting Monitoring at Cape Station
From late July 2025 to February, geophysicists at Lawrence Berkeley National Laboratory (Berkeley Lab) continuously monitored microseismic activity nearly 7,000 feet underground at Fervo Energy's Cape Station EGS site in Utah. Temperatures at this depth reached a staggering 338°F. This effort represents a significant breakthrough in long-term, high-temperature geothermal reservoir monitoring, setting a new record for continuous measurement at such extreme temperatures.
Nori Nakata, a Berkeley Lab staff scientist, emphasized that these high-temperature measurements are vital for geothermal energy production and will aid in expanding EGS operations effectively and safely.
Fervo Energy's Vision and EGS Technology
Fervo Energy's Cape Station, operational since 2023, is a key research site for advancing geothermal development in southwest Utah, an area with subsurface conditions representative of the geothermal-rich American West. Fervo Energy plans to deliver an initial 100 MW of continuous geothermal power from Cape Station by 2026, with a goal of reaching 500 MW.
Geothermal heat is abundant underground, but many rock formations lack the permeability for efficient fluid flow and heat transfer. EGS technology addresses this by circulating water through engineered fractures deep underground to absorb heat, which is then converted into electricity. While most monitoring sensors operate at shallower, cooler depths, new technologies are being developed to withstand the extreme heat at greater depths where geothermal conditions are optimal.
The Critical Role of Continuous Seismic Monitoring
Nakata highlighted the importance of continuous seismic recording for expanding EGS operations. This monitoring enhances understanding of rock fracture development, allowing for better control of fluid injection and circulation within the reservoir to efficiently produce steam for electricity generation.
Continuous monitoring also provides a comprehensive catalog of small seismic events, which helps scientists understand and manage induced seismicity. Increased data enables improved control of reservoir development, reducing the likelihood of larger seismic events that could be felt at the surface.
A seismometer, developed at Berkeley Lab's Geosciences Measurement Facility (GMF) and measuring just under 10 feet long, was deployed 6,995 feet underground at Cape Station on July 27, 2025. This site, located near the U.S. Department of Energy's Frontier Observatory for Research in Geothermal Energy (FORGE), offers valuable data for Fervo to manage and mitigate induced seismic activity risks. Utah has been a geothermal energy producer since 1984, and Fervo continues regular seismic monitoring.
Sireesh Dadi, Fervo Energy's Manager of Data Acquisition and Advanced Analytics, stated that developing reliable high-temperature sensors is transformative for geothermal energy, advancing tools for microseismic monitoring, pressure sensing, and strain sensing to better understand reservoir behavior in real time.
Berkeley Lab's Expertise in Geothermal Innovation
Berkeley Lab's GMF specializes in developing and deploying customized geoscience instruments designed for extended operation in harsh, remote environments. The deployed seismometer is sealed against water seepage and engineered to function without components prone to failure under intense heat.
Berkeley Lab's Energy Geosciences Division has researched geothermal energy for nearly 50 years, starting at The Geysers Field. The team has led collaborations in EGS development, monitoring, and aligned research with technological and material advancements. They have contributed expertise to field-scale demonstrations at sites like Cape Station and Utah FORGE and are involved in DOE-funded projects testing EGS in superhot conditions exceeding 700°F.
The team has also developed widely used software for simulating reservoir processes, aiding in identifying promising EGS sites and tracking performance. By integrating advanced modeling with robust sensors and artificial intelligence, scientists are gaining crucial insights into rock and fluid behavior, essential for expanding geothermal energy and enhancing reservoir management.
Paving the Way for Geothermal Expansion
Nakata concluded that a clear understanding of true reservoir conditions, including rock stress, permeability, fluid pathways, and fracture growth, is critical for EGS to become a major U.S. energy source and to prevent unwanted induced seismicity.
This research is supported by the Office of Geothermal at the U.S. Department of Energy.