Beneath our feet lies a powerful and constant source of energy: the Earth's heat. Berkeley Lab scientists explain the difference between conventional geothermal systems, which tap into naturally occurring underground hot spots, and enhanced geothermal systems (EGS), which create engineered pathways to access heat in more locations. With the potential to deliver abundant and resilient power almost anywhere, EGS could transform the way we think about energy.
(Credit: Jenny Nuss/Lauren Biron/Berkeley Lab)
What's the difference between conventional geothermal energy and enhanced geothermal energy?
Imagine a future where nearly a quarter of the world's electricity comes from a reliable source that's been hiding right beneath our feet – the Earth's heat.
Conventional geothermal systems already tap into this natural resource, which escapes from the Earth's subsurface. You'll often find them near features like volcanoes, geysers or hot springs – places where the Earth's heat is obvious.
In these systems, fluid is pumped underground, where it heats up. When it returns to the surface as steam,we can use it to power turbines and generate electricity. Because the heat is already flowing out, it's relatively easy to harness.
Enhanced geothermal systems – or EGS for short – work differently. The concept has been around since the 1970s and originated in the U.S.
In this enhanced version, fluid is still pumped underground to heat up, but it's targeted at "tight rock" – a type of rock that doesn't have natural cracks or pores for water to flow through. Instead, artificial reservoirs are created by injecting water into the rock and breaking it up, giving the water a path to circulate and pick up heat. From there, it works just like conventional geothermal.
What's exciting about EGS is its potential to provide abundant energy almost anywhere, using just a small amount of land.
Researchers at Berkeley Lab are working to make this technology safer, more reliable, and efficient.
To learn more about enhanced geothermal energy research, visit lbl.gov.
