What is Geothermal Energy?
Geothermal energy is heat derived within the sub-surface of the earth. Water and/or steam carry the geothermal energy to the Earth’s surface. Depending on its characteristics, geothermal energy can be used for heating and cooling purposes or be harnessed to generate clean electricity. However, for electricity, generation high or medium temperature resources are needed, which are usually located close to tectonically active regions.
There are different geothermal technologies with distinct levels of maturity. Technologies for direct uses like district heating, geothermal heat pumps, greenhouses, and for other applications are widely used. The technology for electricity generation from hydrothermal reservoirs with naturally high permeability is also mature and reliable. However, medium temperature fields are more and more used for electricity generation or for combined heat and power thanks to the development of binary cycle technology, in which geothermal fluid is used via heat exchangers to heat a process fluid in a closed loop.
GEOTHERMAL ENERGY IN THE WORLD
Geothermal energy is a key renewable source. It covers a significant share of electricity demand in countries like Iceland, El Salvador, New Zealand, Kenya, and Philippines and more than 90% of heating demand in Iceland.
The geothermal installed capacity was 14,9 GWh globally at yearend 2018, and the top five countries for generating electricity from geothermal energy are the USA, Philippines, Indonesia, Turkey and New Zealand. Non-electricity use has exceeded 70.000 MWt. And the top 5 countries in the world for direct use are the USA, China, Sweden, Belarus and Norway. The world’s first and oldest geothermal power plant is located in Tuscany, Italy. The region is also home to 34 geothermal power plants with a net installed capacity of 761 MW and generating 6 TWh (terawatts) annually. Also, nearly 40 percent of the electricity use in the region is met by geothermal energy.
WHY IS IT IMPORTANT?
Its key advantages are that it is independent of weather conditions and offers a very high capacity factor, which allows geothermal power plants to not only supply base load power, but also auxiliary services for short and long-term flexibility in certain situations.
Geothermal energy represents a clean, cheap and environment-friendly resource. It does not cause carbon emission or air pollution. In Iceland, for example, 95% of buildings are heated by geothermal energy and it ranks among the cleanest cities in the world. Moreover, geothermal energy is available 365 days of the year, unlike other sources of renewable energy.
GEOTHERMAL ENERGY IN TURKEY
Turkey is rich in terms of geothermal energy, as it is located on an active tectonic belt. There are approximately 1.000 natural geothermal springs of varying temperatures across the country.
Turkey has a very high potential for geothermal energy. 78% of the potential areas are located in West Anatolia, 9% in Central Anatolia, 7% in Marmara, 5% in East Anatolia and 1% in other regions. 90% of our geothermal springs have low to moderate temperature, which can be used for direct applications (i.e. heating, spa tourism or various industrial uses). The remaining 10% are suitable for indirect uses (i.e. electricity generation).
Geothermal springs have very broad uses. Today, electricity from geothermal energy is used in Turkey for heating (greenhouses and homes), spa and health tourism, industrial mineral harvesting, fisheries, dehydration, etc. Electricity was first generated from geothermal energy
in 1975, with the erection of Kızıldere Power Plant by General Directorate of MTA, which has 0,5 MWe power.
COMMON MISCONCEPTIONS ABOUT GEOTHERMAL ENERGY
MISCONCEPTION-1: “HABITATS ARE DESTROYED IN AREAS WHERE GEOTHERMAL ENERGY IS PRODUCED.”
Geothermal energy is a completely natural resource. Derived from heating of underground waters, geothermal energy has been in use since archaic times. In ancient Rome, geothermal springs were used as spas and baths and it still remains in use today, preserving our world and our habitats.
MISCONCEPTION-2: “GEOTHERMAL ENERGY TRIGGERS EARTHQUAKES.”
The relationship between geothermal energy and earthquakes has been investigated extensively in numerous national and international studies. The studies have shown that Turkey is located on an earthquake belt and the movement of fault lines has been going on for the past 13 million years. But geothermal energy generation has no effect on the movement of fault lines.
MISCONCEPTION-3: “GEOTHERMAL ENERGY IS NOT A RENEWABLE ENERGY SOURCE, AND IT CANNOT PROVIDE ENERGY INDEFINITELY.”
Geothermal energy is derived from magma in layers close to the surface, and from water, steam and hot rocks, and it will be available for as long as earth exists. It is a sustainable, reliable, environment-friendly and indigenous source of energy, which can be harvested 24/7 regardless of weather conditions.
MISCONCEPTION-4 “ELECTRICITY PRODUCTION FROM GEOTHERMAL ENERGY POLLUTES THE ENVIRONMENT.”
Environmental pollution from geothermal power generation is precluded, as long as the regulatory requirements have been met.
MISCONCEPTION-5 “GEOTHERMAL POWER PLANTS HARM FARMING AND TREES.”
Geothermal power generation is not harmful to wild life, if performed in line with the regulatory requirements. Contrary to claims otherwise, geothermal energy helps enhance agricultural activities. Geothermal energy used for greenhouse farming facilitates harvesting of crops throughout the year.