Geothermal power harnesses deep Earth heat as electricity by injecting underground hot water or steam, forcing it to drive turbines, and producing electricity. Cool water is thereafter pumped underground to maintain the system.
How does the heat reach the surface?
The initial formation of the planet, radioactive decay, and residual core heat produce heat under the Earth’s surface. Under geothermal “hot spots,” heat warms groundwater to high temperatures—usually above 150°C—to form steam or hot water reservoirs. Typically, reservoirs are found near tectonic zones or volcanoes.
What Happens Within a Geothermal Power Plant?
1. Production Well
Drills penetrate deeply into reservoirs of hot water or steam, which have a tendency to rise under pressure.
2. Steam powers a turbine
- Dry steam plants provide natural steam directly to turbines via piping.
- Flash steam power plants are fed high-pressure hot water; when pressure is lost, water flashes into steam to drive turbines.
- Moderate-temperature water is employed in binary cycle power plants to vaporize low-boiling-point secondary fluid for heating, generating vapor to drive turbines.
3. Generator Converts Motion to Electricity
The turbine’s spin powers an electric generator, converting energy into power.
4. Cooling & Reinjection
After passing through the turbine, steam or vapor is condensed in a condenser and reinjected underground through injection wells, with the reservoir pressure maintained constant.
What are the main plant types?
There are three broad categories of geothermal power plants:
- Dry Steam Plants: These employ steam directly from the earth to drive a turbine and produce electricity. It is the most rudimentary and oldest form.
- Flash Steam Plants: These are the most common nowadays. They produce hot water underground, which is converted to steam when the pressure is released. This steam is employed to power the turbine.
- Binary Cycle Plants: These use hot water to heat another liquid having a lower boiling point. That second liquid evaporates and spins the turbine. These plants work well with lower temperature water.
Why This System Is Sustainable?
The closed-loop system, in which used water is recycled back into the reservoir, keeps the water flowing and lessens depletion. This enables geothermal power plants to operate around the clock, providing baseload power.
Posted by Abu Talha
With a background in science at the A-level, Abu Talha has studied subjects including physics, chemistry, mathematics, and biology. Along with his more than 1.5 years of experience in digital marketing, he is passionate about writing about electric vehicles, sustainable energy, and how emerging technologies are influencing the future.
