Alternative energy sources
Geothermal power plants offer one of the most promising ways of generating the alternative sources of energy. Current demand for geothermal energy, as for one of the forms of renewable energy, is primarily caused by the depleting of the fossil fuel reserves.
Geothermal power plant is a kind of power plants generating electricity using geothermal energy obtained from the earth's natural heat.
The advantages of the geothermal power plant are the following:
- An option to use it as a source of geothermal water or a mixture of water and steam (depending on their temperature) for hot water supplying and heating, as well as for eclectic power generation, or, simultaneously, for both;
- Safety for the environment;
- The cost-effectiveness;
- It is practically inexhaustible;
- Complete independence in operating on the environment, time of day or season;
- The efficiency exceeds 90%;
Geothermal energy sources:
- Deposits geothermal dry steam;
- Sources of the wet steam (mixture of hot water and vapor);
- The dry hot rocks heated by magma;
- Magma, which is molten rocks, heated up to 1300 ° C;
Schemes of power generating using hydrothermal resources:
- Direct-dry steam is used;
- The steam, coming directly from the well into a turbine of a generator, is used in direct-type geothermal power plants to generate power;
- Indirect-vapor is used;
- Hot ground water is used in indirect-type geothermal power plants to generate power. The hot ground water of 183°C is pumped at high pressure and then sprayed into a capacity with lower pressure which causes the intense evaporation followed by steam entering generator turbines.
- Mixed (binary) cycle;
- Additional liquid (or gas), with a boiling point lower than that of water, is used in mixed-type geothermal power plants to generate power. They are passed through a heat-exchange unit where geothermal water vaporizes the second liquid, and the vapors produced activate the turbines.