Britannica
Sources used in this answer
- geothermal power - Types of power generation
- Fracking
- Geothermal power - Con 2: Geothermal power plant construction can trigger earthquakes.
- Geothermal power
- Why Is Fracking Harmful?
- Geothermal power - Con 3: Geothermal power plants can endanger water supplies and wildlife.
- volcano - Volcanoes and geothermal energy
How do enhanced geothermal systems differ from oil and natural-gas fracking?
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geothermal energy
The Nesjavellir Geothermal Power Plant, Iceland.
Enhanced geothermal systems (EGS) and oil and natural-gas fracking share similar drilling and high-pressure injection technologies to create or open underground fracture systems in low-permeability rock. However, they differ significantly in their purpose, composition, and environmental impact.123
Key Differences
- Objective: Fracking is used to extract finite fossil fuels—specifically oil and natural gas—from deep rock formations. In contrast, EGS is a method for capturing renewable geothermal energy by circulating a heat-transfer fluid (typically water) through hot, dry rock to transport thermal energy to the surface for electricity generation.4513
- Fluid Composition: Fracking typically utilizes a mixture of water, sand, and chemical additives to prop open fissures and facilitate resource recovery. EGS primarily uses water alone to fracture the rock and transport heat, making it a cleaner process with a lower risk of contaminating groundwater with chemical additives.4536
- Environmental Considerations: Both methods carry the risk of inducing seismic activity, often referred to as "frac-quakes" in the context of oil and gas or "induced seismicity" in geothermal projects. While EGS is considered a cleaner form of energy capture, it still requires careful management to prevent groundwater contamination from dissolved minerals and to avoid water scarcity issues.256