Enhanced Geothermal

Conventional geothermal requires a rare geological gift: hot rock, natural permeability, and water, all in the same place. Enhanced geothermal systems (EGS) ask a different question: what if you could create the reservoir yourself? The Earth is hot everywhere if you drill deep enough. You just need to make the rock permeable.

EGS targets hot dry rock at 3-10 km depth where temperatures exceed 150-200 degrees C but no natural water circulation exists. The process drills two or more wells, then hydraulically fractures the rock between them to create an artificial network of flow paths. Water pumped down the injection well flows through the fractured hot rock, heats up, and returns through the production well as steam or hot water to drive a turbine.

Understand the resource expansion. Conventional geothermal is limited to volcanic regions (Iceland, western US, East Africa). EGS could theoretically work anywhere with sufficient depth, expanding the accessible geothermal resource by orders of magnitude. The US DOE estimates EGS potential at 100+ GW, comparable to total US nuclear capacity.

What is the main obstacle preventing EGS from scaling today?

The engineering challenges. Creating and maintaining fracture networks at 5+ km depth is difficult and expensive. Induced seismicity (small earthquakes from fracturing) has caused project cancellations. Drilling costs increase exponentially with depth. Current EGS projects (like Fervo Energy's Utah site) are demonstrating the technology, but costs remain far above conventional geothermal.

EGS is geothermal's version of what shale technology did for oil and gas: engineering around geological limitations to unlock a vastly larger resource.

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