What exactly is geothermal energy? To put it as simply as possible, geothermal energy is heat stored within the Earth’s core. Geothermal energy like all other energy sources has its advantages and disadvantages but let me first start with positives in using geothermal energy.
Geothermal energy advantages:
Geothermal energy is renewable energy source. This means that world will not eventually run out of geothermal energy like for instance oil. Geothermal energy is renewable energy source because earth’s heat is being constantly replenished by the radioactive decay of minerals at a rate of 30 TW.
Geothermal energy is clean source of energy because geothermal power plants emit minimum carbon emissions. This is because with most geothermal power plants are equipped with emission-control systems to reduce the exhaust of greenhouse gases carried by drawn fluids.
Geothermal energy belongs to energy sources that can be directly used. Just take a look at hot springs that have been used for bathing since ancient times. In modern times geothermal energy is directly used to heat homes via geothermal heat pumps.
Geothermal energy is very reliable source of energy that does not suffer from intermittency like this is the case with some other renewable energy sources, most notably solar and wind. Geothermal heat is available 24-7 and is therefore one of the most reliable renewable energy sources, a one that does not require backup energy storage solution in order to guarantee reliability.
Geothermal power plants have minimal land and freshwater requirements. Solar power plants, for instance, need large area and plenty of water for cooling. Geothermal power plants use only 3.5 square kilometers (1.4 sq mi) per gigawatt of electrical production and require in average 20 liters of freshwater per MW/h.
Geothermal energy disadvantages:
The biggest disadvantage of geothermal energy is high upfront costs, most of which refer to exploitation and drilling. Between 2010 and 2021, the average installed cost for geothermal energy worldwide ranged between 2,700 and 5,600 U.S. dollars per kilowatt, peaking at 5,509 U.S. dollars per kilowatt in 2012.
Geothermal power plants still somewhat lack worldwide appeal though this isn’t the case with geothermal heating because today there are more than 80 countries using geothermal energy for heating purposes in household, commercial and industrial sectors (2022 data). The main reason why world isn’t using more geothermal power is because geothermal power plants are currently cost-effective only in areas near tectonic plate boundaries though the recent technological advances such as EGS (enhanced geothermal systems) should significantly expand the range of viable geothermal resources in years to come.
There is still lack of qualified personnel needed to install geothermal systems. Geothermal energy use isn’t as widely spread or as popular as solar and wind, which means that there is less qualified personnel available to hire and they also cost more.
Local depletion of geothermal resources. This has been the case in several well known geothermal sites such as Geysers. In order to avoid local depletion of geothermal resources extraction of geothermal energy must be closely monitored.
In the end I also have to mention that enhanced geothermal systems can theoretically trigger earthquakes therefore severely affecting land stability if not done carefully.