| Abstract |
Lithuania contains large hydrogeothermal resources confined mainly to major Cambrian and Lower Devonian siliclastic reservoirs comprised by up to 2 km thick sedimentary pile of the Baltic sedimentary basin covering the Early Precambrian crystalline basement of the East European craton. So far, one district heating geothermal power plant is operating in city Klaipėda located at the Baltic Sea shore. Several priority targets were defined for further development of the hydrogeothermal objects that are characterized by exceptionally favorable geological conditions in west Lithuania containing the thickest sedimentary cover (maximum depths) and highest intensity heat flow anomaly. The geothermal balneology is seen as the parallel important application of the geothermal reservoirs. There is a number of resorts chained along the Baltic Sea shore in Lithuania. They are, however, heavily season-depended crowded during the summer season while abandoned during the rest of a year that cause economic-social misbalance of the area. Yet, the shore zone is characterized by largest hidro geothermal resources. Several detailed evaluation studies were carried out recently. Three prospective reservoirs were defined and assessed, i.e. Middle Cambrian, Lower Devonian and Middle Devonian sandstones that are obtained at different depths which, in turn, control the temperatures and chemical composition of a formation water; respectively, about 150 g/l and 70~80°C,70-90 g/1 and 35-40°C, 15-30 g/1 and 25-30°C. It led to some initiatives of the realization of the geothermal balneology objects along the Baltic Sea shore zone (e. g. Kretinga—Palanga area). The information on operation of Klaipėda geothermal demonstration plant (KGDP) and the growth of installed capacity of ground-source heat pump systems are also presented in this paper. As a good practice examples in Lithuania – two case studies are discussed: first, - the residential countryside house with novel geothermal heating system is presented. Heat pump system (with coaxial ground heat exchanger) is operating with solar collector. The summer heat accumulated in the coating soil around vertical borehole is utilized during the first part of winter, whereas since February the solar collector is connected up in order to source higher potential heat for geothermal heat pump. The water accumulation volumes are used for solar heat collecting. second, - the installation of geothermal heating and cooling system (with 140 kW capacity) in the building of “WURTH LIETUVA”, UAB logistics center located in Ukmergė district. |