Geothermal project in Sala

Town of Sala, the county town at Nitra region, is situated on both sides of Vah river. From geological point of view, Sala lies at the east edge of Galanta basin, in the prospective area for geothermal energy utilization. Project documentation for land permit and subsequently building permit was made in 2009. Drilling works started in the end of the same year and the preparation of construction works as well. The project was put into operation in the beginning of 2011. Investor and operator of the geothermal project is company MeT Sala.

Geothermal energy form new well GTŠ-1 with depth of 1 800 m is being used for heat production in existing boiler plant CK31. Geothermal water is being pumped by electric submersible pump with variable speed controller. Flow rate is 15 l/s and temperature 70°C. Water is being delivered via pre-insulated pipe to a separator, where the free gases are being released, and subsequently to a heat exchanger station situated in the area of the boiler plant.

After the utilization of thermal energy in heat exchangers, geothermal water flows through plastic pipe into the recipient, Vah river. Length of supply pipeline is approx 200 m and of discharge pipeline 800 m. Boiler plant CK31 is central heat source of district heating system which supplies surrounding apartment and public buildings in the surroundings. Distribution network is two-pipe system which is connected to pressure independent heat exchanger stations installed in 82 objects. Total annual heat production of CK31 is approx. 87 000 GJ (24 167 MWh), while geothermal energy covers approx. 30%. Two demountable plate heat exchangers made of titanium are installed in geothermal heat exchanger station, the first of which with 1,3 MW heat output for direct return heating water warming and the second with 0,45 MW for heat pump evaporator loop water warming. The heat pump´s maximal heating output in given conditions is 576 kW. Total heat output given into the system by geothermal energy and the heat pump is 1,9 MW.

Geothermal energy combined with the heat pump represents the base load heat source with the maximal working time throughout the year. The existing natural gas boilers are being used as a peak source or possibly as a backup source able to cover 100% of heat demand.

With respect to the parameters of geothermal resource and district heating system, it is impossible to completely replace natural gas usage. However, significant savings of such primary fossil fuel are being reached which of course positively impacts the economy of the heat plant operation. Environmental aspect in reducing CO2 emissions is also important.

Geothermal energy, as one of the cleanest and most stable renewable energy resources, covers 30% of overall annual heat production of CK31, while savings of 843 000 m3 of natural gas per year and CO2 emissions reduction of 1 662 ton per year are achieved.

Successful implementation of the geothermal project in Sala is a very good proof that geothermal energy is, despite of global economical crisis and lack of governmental support, economically and technically favorable and reliable domestic renewable energy resource.