Geothermal Energy To Generate Electricity
Geothermal energy is that energy that can be obtained by man through the use of heat from the interior of the Earth. This type of energy has many applications. One of these applications is the generation of electric power.
Geothermal power plants are similar to other turbine thermoelectric power plants: the heat of an energy source (in the case of geothermal, the heat inside the Earth) is used to heat water or other working fluid. Said fluid rotates the turbine of a generator, producing electricity. Subsequently, the fluid is cooled and returned to the heat source.
Three types of geothermal power generation plants can be distinguished depending on the temperature, depth and quality of the water and steam extracted.
- Dry steam geothermal plants
- Geothermal flash steam or flash steam power plants
- Geothermal plants of binary cycle
Another form of exploitation is the energy from dry and hot rocks: This system consists of pumping water through the hot rocks of the center of the Earth, instead of taking advantage of the hot water from the Earth's interior, by vaporizing and make a turbine move. The advantage of this type of energy use is that it can be used anywhere, not only in active tectonic zones.
In all cases, the condensed vapor and the remains of geothermal fluid are returned to the deposit.
Geothermal dry steam power plants
Flash or flash geothermal steam power plants
The flash steam power plants move hot water at high pressure through wells and introduce it into low pressure tanks. Due to this pressure change, the thermodynamic effect is produced by which liquid water becomes vapor.
Because the center of the Earth is under high pressure, water at this temperature is maintained in liquid state thanks to the laws of thermodynamics. At the moment when liquid water is pumped outwards, where the pressure is atmospheric pressure, it becomes vapor.
The steam generated at the outlet is used to move the turbine that generates the electricity.
The rest of the water that has not been vaporized is returned to the reserve. The remaining liquid water and condensed steam can be injected into the tanks again, making the process potentially sustainable.
Binary cycle geothermal plants
The binary cycle geothermal power plants are the most recent development, and can operate with fluid temperatures of only 57 ° C. Moderately hot water is passed along with another fluid with a boiling point much lower than that of water. This causes the secondary fluid to vaporize and is used to move the turbines.
This is the most common type of geothermal power plant within projects currently under construction. Both the Rankine cycle and the Kalina cycle are used. The thermal efficiency of these plants is approximately 10-13%.
Last review: January 1, 2018