Answers to frequently asked questions (FAQ) regarding exploration and exploitation of geothermal energy

What is geothermal energy ?

The term geothermal is of Greek origin. Geo, meaning earth, and therme means heating, so it is geothermal energy, which comes from the natural heat of the earth. The temperature of the earth varies, and geothermal energy is usable in a wide temperature range, from room temperature to over 150 ° C. For commercial use, it is necessary that the geothermal reservoir is able to provide hydrothermal resources (hot water and steam). Geothermal reservoirs are generally divided into low-temperature (<150 ° C) and high-temperature (> 150 ° C). Generally speaking, high-temperature reservoirs are suitable for, the commercial production of electricity. Geothermal reservoirs can be found in "geothermal systems," which are regionally distributed according to the geological structure, where there is enough heat near the Earth's surface, to make the steam or thermal water on surface of the Earth. Example geothermal systems are deposits of thermal water in Semberija and the Sava and the wider area of ​​the Pannonian Basin.

What are the benefits of using geothermal energy ?

Several attributes makes geothermal energy a good source of energy.

- First, it is clean energy. Energy in this way can be produced without burning fossil fuels such as coal, gas or oil. Geothermal fields produce only about one sixth of carbon dioxide, which is produced by relatively clean gas power plants, and very little or no emissions of nitrogen oxide and sulfur. Binary power plants, which operate with the closed cycle, essentially have no emissions.
- Geothermal energy is available 24 hours a day, 365 days a year. Geothermal power plants have an average availability of 90% or more, compared with 75% for coal power plants.
-Geothermal energy is a domestic and reduces our dependence on foreign oil.

why is geothermal energy considered a renewable resource ?

Because its source is almost unlimited amount of heat which is generated in the Earth's core. Even in areas where geothermal energy depends on the reservoirs of hot water, exploited amount of water can be re-injected into the underground, making it a sustainable source of energy.

Where geothermal energy is found ?

Hydrothermal resources - reservoirs of steam or hot water - are available primarily in the north of the Republic of Srpska and Bosnia and Herzegovina (the circumference of the Pannonian Basin). However, the energy of the Earth can be used in all parts of the territory of the Republic of Srpska and Bosnia and Herzegovina, with a geothermal heat pumps and direct use. Other significant and worldwide present geothermal resources - heat dry rock and magma, for example - are waiting for the future development of technology.

What is the environmental impact of the geothermal energy ?

Geothermal technology offer many advantages for the environment compared to conventional energy:

- Emissions are low. Only the excess vapor is emitted from geothermal "flash" power plants. No emissions are released into the air or fluid discharged by the binary geothermal power plants, which are projected to become the dominant technology in the near future.
- Salts and dissolved minerals contained in geothermal fluids, usually re-injected with excess water back into the reservoir at a depth far below the aquifers of fresh water. This recycling of geothermal water is filling the geothermal reservoir. City of Santa Rosa, California, pipe treated wastewater is conveyed from the city to power plant "Geysers (sr. Geysers)" which is used for re-injection of fluids. This system will extend the life of the reservoir due to the recycled treated wastewater.
- Some geothermal power plants do not produce any solid materials, or deposits, which require disposal in approved locations. Some of these particles are now allocated for sale (zinc, silicon, sulfur, for example), which further increases the value of resources and improvement of the environment.

What is the visual impact of the geothermal energy ?

Systems of remote heating and geothermal heat pumps are easy to integrate into the community with the fact that almost no visual impact. Geothermal power plants use a relatively small area, and do not require storage, transport, and fuel combustion. There is not any kind of emissions or only vapor is visible. These qualities reduce the overall visual impact of the power plants in the beauty of the region.

Is it possible to drain the geothermal reserves ?

Long-term sustainability of geothermal energy are shown in the field Lardarello in Italy since 1913.g, the Vairakei field in New Zealand since 1958.g and in field Geysers in California since 1960.
Drop of preasure and production occurred in some power plants, and operators have begun the re-injection of water in order to maintain reservoir pressure. Pipes of treated wastewater from the city of Santa Rosa, California, are taken to the "Geysers" (sr. Geysers) power plant, to be used as a retroactive injected liquid, resulting in prolonging the service life while the wastewater is recycled.

How much it costs to develop the geothermal power plant ?

The cost of geothermal power plants have long been weighted towards the costs, not the fuel to display them. Drilling of geothermal wells and construction of pipelines come first, then the analysis of resources based on information from drilling. The following is a project of the actual plant. Construction of the plant is usually completed at the same time with the final elaboration of the geothermal field. The starting price for the geothermal field and power plant is about $ 2,500 per kW installed in the US, probably $ 3,000 to $ 5,000 / kW for small (<1 MW) power plant. Operation and maintenance costs are in the range of $ 0.01 to $ 0.03 per kWh. Most geothermal power plants can operate at more than 90% availability (ie. More than 90% of the time), but the work on the 97% or 98% can increase maintenance costs. The higher price of electricity-justify starting up 98% of the time, because the resulting higher maintenance costs will be reclaimed.

What are the characteristics of good terrain for the geothermal power plants ?

Thermal water with low mineralization and low gas content, the shallow aquifer for the production and re-injection of water, the location on private land to simplify the license, proximity to existing transmission lines, as well as the availability of fresh water for cooling vapors. Geothermal fluid temperature should be at least 150 ° C, although some power plants operate at temperatures of fluids and less than 100 ° C.

How much water is needed for geothermal power plant ?

The required flow rate depends on the temperature of the geothermal fluid, characteristics of the environment (for renewability), also the pumping energy required for the supply and management of thermal water. Excluding pumping of thermal water, geothermal power plant with closed-loop, of the binary cycle it will take 28 to 38 liters per second (l / s) in order to produce 1 MW, from 150 ° C fluid with air temperature of 15.5 ° C. If the fluid temperature only 100 ° C, it will take 82 to 95 l / s, in order to produce same amount of energy. If evaporative cooling system is used, it will take 3 to 5 l / s of renewable (clean), cooling water for the production of 1 MW.

Is the geothermal energy usable only in places where thermal water is present ?

No. Geothermal energy can be taken, almost on all terrains, through the use of heat exchangers or. heat pumps.

Who gives the permission for geothermal energy exploration ?

To explore geothermal energy or underground thermal water and thermo-mineral water it is required to fill application for a concession to the competent Ministry of Industry, Mining and Energy of the Republic of Serbian (for the territory of the Republic of Srpska).

What is required for concession on thermal water exploitation ?

With the application for a concession it is necessary to submit the following documentation:
- Project detailed hydrogeological investigations of thermal water,
- Pre-study of economic feasibility of exploitation of thermal water,
- Three copies of the graphic representation of the proposed boundaries of the concession fields in the topographic scale of 1: 25,000.

Who can make technical documentation in order to get the concession on exploration and exploitation of thermal water and thermomineral water ?

Companies and institutions which meet the requirements of the Act on geological research (Fig. Gazette of the Republic of Srpska No. 51/04 and No. 75/10) and the Ordinance on technical and technological conditions for the activity of geological exploration (Fig. Gazette of the Republic of Srpska No. 21 / 11). One of these is "IPIN" Ltd. Institute for Applied Geology and waterengineering from Bijeljina.

Who can explore thermomineral water ?

Companies and institutions which meet the requirements of the Act on geological research (Fig. Gazette of the Republic of Srpska No. 51/04 and No. 75/10) and the Ordinance on technical and technological conditions for the activity of geological exploration (Fig. Gazette of the Republic of Srpska No. 21 / 11). One of these is "IPIN" Ltd. Institute for Applied Geology and waterengineering from Bijeljina.

What is the cost of one geothermal drillhole ?

In the current regional framework Balkans, geothermal borehole depth of 2000 m will cost up to € 2,000,000. However, it should be noted that the price difference can be significant, which depends of the geological structure of the field, the occurrence of elevated pore pressure and gas, the level of analysis, measurement and recording during the execution of drilling, anticipated delays, dimensions and type of borehole casing and other.
To obtain a bid for geothermal wells, it is necessary to have a project for geothermal well and clearly defined Bill of Quantity with the technical description of work to do, which is made by companies and institutions which meet the requirements of the Act on geological research (Fig. Gazette of the Republic of Srpska No. 51/04 and No. 75/10 ), as well as the Ordinance on the technical and technological conditions for the activity of geological exploration (Fig. Gazette of the Republic of Srpska No. 21/11). One of these is "IPIN" Ltd. Institute for Applied Geology and waterengineering from Bijeljina

Is it possible, and how to use the heat from the ground with heat pumps ?

The use of heat pumps is explained in detail on the website: Answers to frequently asked questions FAQ regarding geothermal system using the heat pump.