Geothermal is the name given to the heat accumulated at different depths underground. It is formed by the combination of the words “geo” and “thermal”. The word geo means earth, and thermal means heat. Water, steam and gases containing many different elements and minerals form the geothermal stream. It is a renewable, sustainable, safe and environmentally friendly green energy source. It is primary energy since it does not undergo any energy transformation. Since there is no combustion process, carbon emission is close to zero.
Geothermal energy can be described as one of the oldest sources used. When we look at the historical process, we see that people have been using geothermal energy for thousands of years in cooking, heating and hot springs. Evidence that it was used in the production of products such as pottery, glass, textiles and creams in 10000 BC has also taken its place in the researches conducted in the Mediterranean Region.
Geothermal energy, which has been in our lives for a very long time, started to be used for electricity production in the early 1900s, and in order to meet the increasing power demand, it was first tested in Larderello in 1904 by Prince Piero Ginori Conti, and it was seen that the energy required for 4 light bulbs was successfully provided in the first successful trial.
In the new world order and with new technological developments, the use of geothermal energy has become less costly and more efficient. It is thought that the geothermal resources that the world has are theoretically sufficient to meet the energy consumption of humanity. It is also doubtless that it can become an indispensable source for energy production by providing more efficiency with government incentives and new techniques to be found.
So, can geothermal energy be considered a type of renewable energy? Of course, geothermal energy is a renewable energy source. Because the heat coming from deep underground is constantly renewed and the risk of depletion is very low. Geothermal energy originates from natural radioactive processes inside the earth and the heat produced by magma. Since these processes will continue for billions of years, geothermal energy is considered a sustainable source.
On the other hand, this type of energy is renewed by natural processes. The continuous production of heat in the Earth’s core supports the geothermal energy source. It is used in the long term. If the resources are managed sustainably (e.g. correct use of reservoirs), geothermal energy can be used for a long time.
Geothermal energy is a preferred energy source because it is clean and safe. Turkey is among the countries with geothermal energy potential. Our country ranks 1st among European countries in terms of geothermal potential and 4th in the world in terms of installed capacity. Today, the top five countries that produce electricity with geothermal energy are as follows;
- USA; It is the largest geothermal energy producer in the world. “The Geysers” field in California is an important example.
- Indonesia; It has great potential thanks to its volcanic structure and is rapidly increasing its capacity.
- Philippines; It has been one of the leading countries in geothermal energy production for many years.
- Turkey; It has made major investments in geothermal energy in recent years. It ranks 4th or 5th in the world rankings and intensive production is carried out especially in Aydın, Denizli and Manisa regions. Turkey is one of the leading countries in the world in terms of geothermal energy potential. As of 2024, Turkey’s installed geothermal electricity production capacity has exceeded 2 GW. In addition, there is widespread use in areas such as thermal tourism and heating.
- Geothermal energy is considered a strategic resource for local development and energy independence. In addition, there are a total of 32 geothermal power plants operating in Turkey. The provinces where the plants are installed and the number of plants are as follows: Aydın (20), Denizli (5), Manisa (5), Çanakkale (2). In addition; Work continues to establish 4 geothermal power plants in Aydın, 2 in Manisa and 1 in Denizli.
- Kenya is the country that uses geothermal energy most effectively in Africa.
There are no risks such as fire, explosion or poisoning in the use of geothermal resources. It is also ecologically safe as it does not harm the environment. The efficiency achieved with geothermal energy is over 95%. Production facilities are at the lowest level compared to the production areas of other energy sources.
When looking at Geothermal Energy Worldwide; Geothermal energy is an important renewable resource. It covers a significant portion of electricity demand in countries such as Iceland, El Salvador, New Zealand, Italy, Kenya and the Philippines, and more than 90% of heating demand in Iceland.
The top 5 countries in the world in direct use applications are the USA, China, Sweden, Belarus and Norway. The world’s first and oldest geothermal power plant is located in the Tuscany region of Italy. The 34 geothermal power plants in this region have a net installed capacity of 761 MW and produce approximately 6 TWh (terawatts) of electricity per year. In addition, nearly 40 percent of the region’s electricity is provided by geothermal energy.
- Installed Capacity:
As of 2023, the installed capacity of geothermal energy worldwide is approximately 16 GW. This capacity used in electricity production constitutes a portion of the total renewable energy resources. However, its use is limited according to its potential.
- Areas of Use:
Geothermal energy use has become increasingly preferred among renewable energy sources. The areas of use of geothermal energy can be listed as follows;
- Electricity generation.
- Applications such as central heating, central cooling, greenhouse heating.
- Drying processes requiring heat.
- Production of chemical substances and minerals.
- Thermal tourism spas.
- Aquaculture.
- Production of drinking water containing minerals.
- How is Electricity Produced from Geothermal Energy?
There are several different types of power plants for electricity production with geothermal energy sources. Although there are design differences in the power plants, they use similar methods during production. Power plants can be of 3 different types. These are;
Dry steam power plants: Dry steam coming from the source is used directly to turn the turbines.
Flash steam power plants: Geothermal fluid coming from the source with high pressure is converted into steam and the turbine is rotated.
Double cycle power plants: Hot geothermal fluid is used to heat and vaporize a second fluid. The evaporated second fluid is directed to the turbines.
The Future and Results of Geothermal Energy;
The economic use of geothermal resources close to the earth’s surface is limited, but this situation may change with developing technologies. Geothermal energy plays an important role in combating climate change due to its low carbon emissions.
- Renewable Energy Need: The increasing energy demand in the world and the environmental effects of fossil fuels are increasing the interest in renewable energy sources such as geothermal. Being a sustainable source may allow geothermal to have a larger share in energy production in the future.
- Technological Developments: New technologies allow geothermal energy to be extracted and used more efficiently. In particular, techniques that allow the opening of deep geothermal wells can increase the energy potential.
- Energy Diversification: Geothermal energy allows countries to diversify their energy portfolio. This can increase energy independence and reduce economic and political risks.
- Urban Use: Geothermal energy can be used more and more not only for electricity generation, but also in heating and cooling systems, agriculture (greenhouse heating) and industrial processes. 5. Carbon Neutrality: Global targets to reduce carbon emissions are encouraging investments in geothermal energy. In particular, funding from the European Union and other countries in this area will support future growth.
As a result, geothermal energy will play an important role in the future, both environmentally and economically. However, careful management and regulatory measures are required for sustainable use.
Sources;
https://www.enerjiatlasi.com/en-buyuk/jeotermal
https://yenader.org/tr_tr/jeotermal-enerji-nedir/
https://www.jeotermaldernegi.org.tr/sayfalar-Dunya-da-Jeotermal
https://geothermie.brussels/en/the-principles-of-geothermics/what-is-geothermics
https://www.sciencedirect.com/science/article/abs/pii/S0377027324002531
https://en.wikipedia.org/wiki/Geothermal_energy
https://www.mta.gov.tr/en/arastirmalar/jeotermal-enerji-arastirmalari