Geothermal energy resources in Poland - Overview of the current state of knowledge

Geothermal energy, which is one of renewable energy sources, is the internal heat of the Earth. Currently in Poland hydrogeothermal resources are utilized, for which the energy carrier is hot groundwater produced with the wells. Petrogeothermal energy resources, i.e. resources of heat accumulated in rocks for which the energy carriers are media injected through wells into the hot rock formations has not yet been utilized in Poland. However the research work tending to assess the possibility of utilization of this type of energy was carried out. The results are particularly important in the context of forecasts of geothermal energy sector development. Although technology of petrogeothermal resources utilization is in the experimental stage, is considered to be the technology of future. In Poland, low-temperature geothermal resources occurs, related mainly to sedimentary rocks - sandstones, limestones, dolomites, rarely with igneous rocks (crystalline, volcanic). Depending on the hydrogeothermal parameters these resources may be used for different purposes: first of all for heating, but also for therapeutic and recreational purposes. Research of the possibilities of using geothermal resources (both petro and hydrogeothermal) for electricity production are carried out. The article presents the actual state of knowledge about geothermal resources in Poland as well as possibility of them utilization for different purposes. In many parts of the Poland significant unused potential of geothermal waters and energy exist.