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How much is the efficiency of geothermal plant?
28%
15%
42%
30%
15%
Quick Summary: The thermal efficiency of a geothermal power plant is typically low, ranging between 10% and 20%, with an average around 15%. This low efficiency is primarily due to the relatively low temperature of the geothermal steam or brine compared to the high-temperature combustion gases used in fossil fuel-based power plants.
The thermal efficiency of a geothermal power plant is typically low, ranging between 10% and 20%, with an average around 15%. This low efficiency is primarily due to the relatively low temperature of the geothermal steam or brine compared to the high-temperature combustion gases used in fossil fuel-based power plants.
η=QinW×100 — Definition of thermal efficiency
ηmax=1−THTL — Carnot efficiency limit
Geothermal plants convert thermal energy from the earth into mechanical energy using steam turbines. According to the Carnot cycle, efficiency is defined as η=1−ThotTcold, where Thot is the temperature of the geothermal resource. Because geothermal reservoirs typically provide temperatures between 150°C and 300°C (significantly lower than coal or nuclear plants), the theoretical and practical efficiency limits remain low.
Geothermal fluids often contain non-condensable gases (NCGs) which reduce vacuum in the condenser, further lowering efficiency.
Efficiency depends heavily on the temperature of the geothermal source (Enthalpy).
Modern binary cycle plants improve efficiency for lower temperature resources but remain in the 10-15% range.
Base load power supply (constant availability)
Extremely low greenhouse gas emissions
Small land footprint compared to solar or wind farms
Low thermal efficiency compared to Rankine cycle plants
High initial drilling and exploration costs
Potential for land subsidence and localized seismic activity
Base load electricity generation
District heating systems
Industrial process heating
Fossil fuel power plants typically operate at 35% to 45% efficiency.
The 15% value represents the standard range for high-enthalpy steam geothermal plants.
B is correct — Geothermal power plants typically operate at an efficiency of approximately 15% due to the low-temperature nature of the geothermal heat source.
Always remember that efficiency in thermal plants is strictly bound by the Second Law of Thermodynamics; the lower the source temperature (as in geothermal), the lower the possible cycle efficiency.