Explaining the Different Types of Geothermal Power Plants

There are at least three general types of geothermal power plants that are credited in harnessing the heat from the Earth and transforming this to useable electricity. And all these three plants operate using a different set of technology that converts the heat of the Earth into useable energy like electricity. The three conversion technologies that are used separately by the three types of geothermal plants include dry steam, flash and binary cycle. Thus the three general types of these plants include the dry steam power plants, the flash steam power plants and the binary cycle power plants. Each of these plants is described below.

What to expect from the dry steam power plant

An example of this geothermal plant can be seen in The Geysers in California. The Geysers is a collection of 22 geothermal plants that sources its heat and energy from more than 350 wells. This is located in San Francisco, California and considered as the largest in the world in terms of capacity. The Geysers and the other examples of plants that run of dry steam make use of steam in order to run the turbines and at the same time run the generator that produces the electricity. The nice thing about the use of steam is that no fossil fuels are used, thus there are no significant impacts to the environment. Also thanks to steam, the associated costs related to the transport and the storage of the fuels is removed.

How does a flash steam power plant works

This is the most common type of geothermal power plant. For this type of plant, liquids that reach temperatures of 200 degree Celsius and more and are pumped at high pressure in the surface, and the pressure is dropped that will transform the water into steam. Just like the dry steam plant, the steam that is produced is the energy that is used to power the turbine and the generator. For the excess water, this will be pumped backed into the second tank and will be flashed again in order to generate the steam needed to power the generator.

How binary cycle power plant operates

The dry steam power plant and the flash steam plant are usually used in areas where there are multiple sources of high-temperature hydrothermal water. But in areas where there is moderate-temperature and these plants will not work, the option is to adopt the binary cycle power plant. For this type of plant, even hydrothermal water that has a temperature of just below 400 degrees Fahrenheit will be used. There are two types of fluids that are used here, the hot geothermal fluid and the secondary fluid that has a much lower boiling point. These two liquids with different temperatures are made to pass the heat exchanger, and the heat of the geothermal fluid will cause the second fluid to ‘flash’ into vapor which is in turn used to power the turbine and the generators.

Of the three different types of plants that make use geothermal energy, the binary cycle is the one that is getting the bulk of attention. The reason for this is that this expands the possible future locations of geothermal plants, that even if the area is not within the ‘Ring of Fire’ and the water temperature is not that high, still geothermal energy can be generated.