There exist numerous geothermal technologies exhibiting varying levels of maturity, that can operate on different ranges of temperature.
Two of the most notable applications of geothermal energy include district heating and electricity generation.
District heating
Consisting mainly of a central heat production facility, a heat distribution pipe network and individual heat exchangers, geothermal district heating systems operate by transferring geothermal heat to indoor spaces and hot water systems. Numerous types of geothermal technologies can be used for the ground extraction and transfer process.
For example, systems using shallow geothermal resources operate on large heat pumps. Since these systems have the ability to reach temperatures beyond 80°C, they prove useful for more than just residential heating. Additionally, hot water can also be used for heating and cooling purposes.
Electricity generation
Generating electricity from geothermal energy involves converting the heat extracted from beneath the earth’s surface into electrical power. Electricity is obtained by turbines driven by steam produced using fluids from underground reservoirs. Dry steam, flash steam and binary cycle power plants are the three main types of geothermal technologies used.
Among these, flash steam power plants that use high-temperature water from geothermal reservoirs are the most common. Dry steam power plants on the other hand, use high-pressure, high-temperature steam directly from the earth to turn turbines connected to generators. Lastly, binary cycle power plants work by using a secondary working fluid contained in a closed loop, having a lower boiling point than water.