GEOTHERMAL | Energy Dream Map

Geothermal

This technology takes advantage of temperatures of the underground soil or water reservoirs. It is used for three main purposes:

Direct Use: The direct use of geothermal energy goes back to ancient times when people used hot water reservoirs for many different purposes, such as cooking or bathing. Nowadays, the water from these reservoirs is pumped and used as a renewable heat source for buildings, and agricultural or industrial processes.
Heat pumps: Heat pumps are used as a replacement for air conditioning. Since at a depth of 3 m, the soil is at a constant temperature range of 10-16 ºC, it is possible to use a heat exchanger that provides constant cooling in the summer and heating in the winter, without the need to use any combustion system.
Geothermal power: Geothermal power uses hot water from underground reservoirs, which have temperatures higher than 100 ºC, as a replacement for combustion boilers in Rankine cycle power plants. In dry steam power plants (temperatures above 230 ºC), vapor from the reservoirs is pumped naturally using the pressure of the reservoir. In flash steam systems (temperatures above 182 ºC), which are the most common, water is pumped to the surface, and changes into vapor due to the pressure difference. If the temperature is under 182 ºC, a binary cycle is used, in which water is pumped and transfers heat to a different working fluid.

In 2015, Geothermal energy was the source of 0.330% of the World’s production of electricity and 0.250% of the production of heat.

Advantages:

Renewable source of energy.
Great electric and heating potential.
Used for various purposes.
Quality and cheap heating system for homeowners, with no use of fuels.
Low visual impact on natural sights when comparing with other renewable sources.

Disadvantages:

High initial investment.
Water must be pumped back to the reservoir to make the process renewable.
High cost of constantly pumping water from the underground reservoirs and back (after the cycle is complete).
Produced in remote places, requiring transportation through many kilometers, with consequent expenses and efficiency losses.
Requires the use of safety measures to block emissions of pollutant gases into the atmosphere.
Risk of earthquakes caused by drilling and pumping water back to the reservoirs.