Below is a diagram of a geothermal power station. The diagram outlines the basic design of a dry steam power plant – one of the oldest designs dating back to the early 1900s. The simplicity of this design ensures dry steam power plants are highly efficient, even in today’s environment.
The above diagram of a geothermal power station shows how the injection well pumps fluids into layers of hot rocks deep within the earth. The fluid is heated by the rocks to a point where it becomes steam. Dry steam is then extracted from deep within the earth via what is known as the production well.
The steam in the production well (as shown by the arrows in the diagram) rises up to the turbine. The steam is of very high pressure and is able to turn the turbine. This then allows the turbine to turn the generator, thus resulting in the production of geothermal power.
The injection well has many other benefits, yet the main advantage of an injection well is for the safe disposal of geothermal fluids as large amounts of fluids (in the form of steam or water) are extracted from low lying rocks in the geothermal power production process.
Another important advantage of the use of an injection well (as shown in the power station diagram) is to avoid subsidence. This is very important in areas where geothermal power stations, homes, industry or businesses co-exist together, as subsidence can cause substantial damage to many properties.
The subsidence from geothermal power plants without the presence of an injection well is caused when large amounts of fluids are extracted from low lying rocks, and not replaced. This can leave large areas deep within the ground which will, over time, subside back into position.
The use of geothermal power in California is a prime example of where the use of injection wells in a geothermal power plants design is extremely important.
This method of extracting fluids to produce geothermal power (as shown in the diagram) is still widely used across the world in geothermal energy hot spots due to the simplicity of design and overall efficiency and power output of the design.
Geothermal energy is very clean, is renewable, and allows for the elimination of fossil fuels in the power production process. The energy produced from geothermal pockets can help our environment by taking some strain off fossil fuel power stations.
Unfortunately, there are only a handful of areas across the globe that are able to benefit from the placement of highly efficient geothermal power stations.
Interested in learning more about the advantages and disadvantages of this renewable energy source? If so, we have a page dedicated to the pros and cons of geothermal energy.