EGS Frequently Asked Questions
What is EGS technology?
Enhanced Geothermal Systems (EGS) expands the potential of geothermal energy by orders of magnitude. The traditional geothermal approach relies on finding naturally occurring pockets of steam and hot water. The EGS process, by comparison, replicates these conditions by fracturing hot rock, circulating water through the system, and using the resulting steam to produce electricity in a conventional turbine. The water is then re-injected back into the rock, where the cycle begins again in a closed loop.
EGS technologies go by many names including: Engineered Geothermal Systems (EGS), Hot Dry Rock (HDR), Hot Fractured Rock (HFR), Deep Earth Geothermal, and Deep Geothermal.
To see how an EGS system works, check out our SketchUp models.
Why EGS?
EGS is a utility-scale, base-load, and renewable energy source that could produce electricity cheaper than coal. Since EGS builds the geothermal reservoir by design, EGS projects can be made large enough to produce as much power as a typical natural gas or coal power plant (500 – 1,000 MW). Everywhere on earth, the deeper you go, the hotter it gets, meaning EGS can be developed in many areas across the world. EGS is a base-load resource, meaning it can run 24 hours a day regardless of weather. A recent report by MIT on EGS estimated 2% of the heat below the continental United States could provide 2,500 times the country’s total annual energy use.
Where can we do EGS?
EGS can theoretically be developed anywhere there is sufficiently hot rock (above 150 degrees centigrade). Because drilling deep is costly today, EGS is currently most economical in shallow, high temperature zones. All 50 US states have EGS resources at varying depths. As drilling technology improves, it will become more economical to develop deeper resources, unlocking the ubiquitous heat of the earth.