Geothermal energy refers to the heat energy in the earth’s crust. Vapor dominated geothermal system refers to the areas or unique regions characterized by the exclusive extraction of steam from geothermal reservoirs. These areas are reported worldwide and are a subject of study from a varying range of perspectives. These systems are ideal for generating electricity at the lowest possible cost and with minimal issues. However, these geothermal systems, also known as dry-steam power plants, are extremely rare. Some examples of geothermal sites around the world include the famous Geysers in the United States, the impressive Larderello in Italy, and the awe-inspiring Matsukawa in Japan.
Working Principle of Vapor-Dominated Geothermal System
The process involves gathering dry steam from wells, purifying it by eliminating abrasive particles, and then channeling it through turbines to power electric generators, following the regular course. One crucial distinction between this system and a traditional steam turbine-generator system considering fossil fuel is that the geothermal steam is supplied at a much lower temperature and pressure. The nearly saturated dry steam from the bottom of the well is used at 200° Celsius, and it may have to shut off the pressure of about 35 bar. Additionally, note that the well’s pressure drop is directly related to the superheat at the wellhead.
The steam expands in the turbine and enters the condenser, increasing the volume of cooling water. Some heat is also lost through evaporation in the cooling tower and the rest is injected into the disposal ground. However, the turbine’s steam is mixed with the cooling water from the cooling tower, creating a saturated vapor. This mixture is then pumped back into the cooling tower.
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