Sustainable Utilization of Low Enthalpy Geothermal Resources to Electricity Generation through a Cascade System

The article presents an assessment of the potential for using low temperature geothermal water from the C-PIG-1 well (Malopolskie Voivodship, southern Poland) for electricity generation, as the first stage in a geothermal cascade system. The C-PIG-1 well is characterised by a temperature of geothermal water of 82 °C and a maximum flow rate of 51.22 kg/s. Geothermal water is currently only utilised for recreation purposes in swimming pools. In such locations, with the potential to use renewable energy for energetic purposes, the possibility of comprehensive management of the geothermal waters extracted should be considered both in the first stage of the cascade and after recreational use. Thermodynamic calculations were conducted assuming the use of the Organic Rankine Cycle (ORC) or Kalina Cycle. Two variants were analysed—the use of the maximum flow rate of geothermal waters and partial use with an assumption of a priority for recreational/heating purposes. The analysis and calculations indicate that the gross capacity in the most optimistic variant will not exceed 250 kW for the ORC and 440 kW for the Kalina Cycle. As far as the gross electricity generation is concerned, for ORC this will not exceed 1.9 GWh/year and for the Kalina Cycle it will not exceed 3.5 GWh/year.