Geothermal is a source of heat energy contained in hot water, water vapor, and rocks along with associated minerals and other gases that are genetically inseparable in a geothermal system. While geothermal energy is energy derived from heat contained in the bowels of the earth and generally associated with the presence of volcanoes.
Technically, the water sourced from it from the rain will seep into the rocks below the ground to reach the reservoir rock. This water is then heated by magma which becomes the main heat source so it turns into hot water or steam (thermal fluid) with a temperature range of 240-310’C. The thermal fluid can be used to generate electrical energy by drilling (drilling) and flowing thermal fluid to drive the turbine and rotate the generator to produce electrical energy. Thermal fluids are then injected back into the reservoir through reinjection wells to maintain fluid and heat balance so that the geothermal system is sustainable. Therefore the need for clean water for households will not be disturbed by geothermal activities considering that the geothermal fluid used for electricity generation does not originate from surface water but originates from a geothermal reservoir with a depth of 1,500.d. 2500 meters.
Geothermal activities must also pay attention to environmental protection considering that the sustainability of geothermal energy is very dependent on the surrounding environment including animals and plants. Geothermal is a very environmentally friendly energy, where CO2 produced from PLTP is only 1.5% of PLTU and 2.7% of PLTG
The general characteristics of geothermal energy include:
(1) Clean, environmentally friendly and sustainable sources of energy.
(2) Can not be exported, it can only be used for consumption in (indigenous) countries.
(3) Free from the risk of increasing (fluctuating) fossil fuels.
(4) It does not depend on the weather, suppliers, and the availability of transportation and loading and unloading facilities in the fuel supply.
(5) Does not require extensive land.
Environmentally friendly is one of the characteristics of geothermal energy which must be underlined. Geothermal energy is environmentally friendly, not only in terms of production but also in aspects of use, so that its impact plays a positive role in every resource. When carrying out the development and manufacturing process, geothermal power is completely free of emissions. There is no carbon used for production, then the entire procedure has also been free of sulfur which has generally been removed from other processes carried out. The use of geothermal energy will not cause pollution to the environment. Therefore the effects of global warming caused by emissions from oil ingredients will decrease. In its use as a geothermal power plant, it will not require fuel oil that can cause air pollution.
As stipulated in Republic of Indonesia Law Number 21 of 2017 concerning geothermal energy, it is environmentally friendly energy whose potential is large and its utilization is not optimal, so it needs to be planned and integrated in an effort to reduce dependence on fossil energy.