The practice of evaluation of recommended areas for geothermal concessions in Hungary and its relation with the register systems

Abstract

This study briefly describes the recently used Hungarian registration system for geothermal energy and the currently used assessment system for proposed areas for geothermal concessions. With the help of a practical example, a presentation is given of the methodology needed to develop the compliance with an international geothermal evaluation system. For the prioritisation of prospective areas of geothermal research — alongside geological and hydrogeological circumstances — the exploitation feasibility and the socioeconomic viability of geothermal energy also need to be considered. Consequently, this becomes more complicated than a simple estimation of reserves based on geoscience. At present, geothermal assets and stock records have no officially accepted international standard; in fact, the “Australian/Canadian standard for research findings, and the reporting of the assets of geothermal stocks” is usually employed in place of an international standard. Even though the development of a Hungarian system similar to the “Australian/Canadian standard” could be aimed at, it would still not be possible to bring about the harmonization between the systems merely by carrying out a direct transfer of existing data. In the Hungarian practice, the terms of calculation and classification of geothermal assets are mixed together. To put it more precisely, it turned out that the current Hungarian classification system is not compatible with any international classification system. A volumetric method is usually used for the prognosis of a geothermal reserve, but the idea of exploitability is not included in the calculation. This study applies the ratio of thermal energy exploitable from hot water and the total heat content of volume in order to calculate exploitable reserves. Geothermal reserves can be established only where a geothermal protective area around the well has been designated and geothermal power generation has started. The inventory calculation data here is based on the data referring to the reserves of an accepted research final report. (This is due to the fact that no identified geothermal protective area is available.) Given that the size of the territory of the protected area is controlled by the desired production quantity, the level of geological knowledge may increase or decrease the calculated value of an area.