How does geothermal energy generate electricity, and what are its main limitations?

• A. Uses heat from the Earth to produce steam that drives a turbine; limitations include resource location, sustainable reservoir management, upfront costs, and surface instability.
• B. Uses wind to heat water.
• C. Is entirely unlimited with no costs.
• D. Produces energy without any environmental impact.

Answer: (A)

Geothermal electricity relies on heat from inside the Earth to heat a working fluid into steam, which then drives a turbine connected to a generator to produce power. The key limitations come from where this resource exists and how it must be managed: you can only tap it where there is accessible hot rock and groundwater, which limits-site availability; sustaining the resource requires careful reservoir management, including reinjecting fluids to maintain pressure and prevent depletion; the upfront costs of drilling wells and building the plant can be substantial; and there can be surface effects such as land subsidence or induced seismicity from fluid extraction and injection.

Other options misstate the energy source, suggesting heat from wind, unlimited or zero-cost energy, or no environmental impact, which do not align with how geothermal systems actually operate and their real-world tradeoffs.