What is geothermal energy and what is Enhanced Geothermal Systems (EGS)?

• A. Geothermal energy uses heat from the Earth's surface temperature only
• B. Geothermal energy uses heat from the Earth; EGS expands access by fracturing rock to create artificial reservoirs where natural hot water is scarce
• C. Geothermal energy relies on solar radiation to heat water
• D. Geothermal energy is always readily available in all locations

Answer: (B)

Geothermal energy taps heat stored inside the Earth. Natural hydrothermal systems use hot rocks with circulating fluids to produce steam or hot water that can drive turbines. Enhanced Geothermal Systems expand access by fracturing rock to create artificial reservoirs where natural hot water or permeability is scarce. By injecting water, circulating it through the hot rock, and bringing it back as steam or hot water, energy can be produced in places that lack natural geothermal fluids.

The other ideas don’t fit: geothermal energy comes from deep Earth heat, not surface temperature alone; it isn’t powered by solar radiation; and geothermal potential isn’t guaranteed everywhere—location, rock temperature, and permeability determine feasibility.