The Polish Ministry of Environment and the Ministry of Climate have presented, last week, a project to use photovoltaics and heat pumps to revive a failed geothermal project located in Gminą Sękowa, Gorlice county, in the Lesser Poland province in southern Poland.
The geothermal project, called Sękowa GT-1, originally consisted of a borehole with a depth of 3km and the geothermal energy that was expected to be extracted from the hole was intended to be used for district heating. “Geothermal water was expected to have a temperature of approx. 60 degrees Celsius and a capacity of 40-70m3 per hour,” the Polish government said in a statement. “However, no water with the assumed parameters was found in the borehole.”
After the borehole was found to be unusable, researchers from the Institute of Mineral and Energy Economy at the Polish Academy of Sciences, along with other partners, have begun investigating how it may be recovered for other purposes and identified the use of a deep-borehole heat exchanger (DBHE), which is an alternative approach to utilizing geothermal energy, as the most suitable. A DBHE extracts heat from medium–depth geothermal energy with a depth of up to 3km, and provides a high–temperature heat source for medium–depth geothermal heat pump systems. The heat generated by the heat pumps can then reach temperatures of up to 90 degrees Celsius and be used for space heating.
The DBHE used in the project planned in Gminą Sękowa is able to reach the expected water temperature of 60 degrees Celsius and to provide heat to buildings located nearby and a recreational center, including a swimming pool. The heat demand of this complex is estimated at approximately 3,768 gigajoule per year. A PV system with a surface of around 150m2 will be used to power the heat pumps and the circulation pump of the DBHE. Excess electricity from the array will be injected into the grid when the DBHE is not operating and grid electricity will be used when the PV system is not delivering power.