Geothermal Power Plant Žiar
About the Project
After the completion of the geological survey and the administrative preparation of the assignment, in March 2021, the company PW Energy has introduced the project for the utilization of geothermal energy for power production in the Žiar nad Hronom region. In 2022, a partnership between PW Energy and SSE Holding was agreed and the project is now being conducted by a joint company PW geoenergy.
Electricity generation will take place in a facility based on the ORC (Organic Rankine Cycle), with an installed electrical capacity of 6.3 to 6.5 MWe.
The power plant will utilize the energy using six wells (three production and three re-injection) in a closed loop with re-injection of the thermally exploited geothermal water, thanks to which the water will be reused in the production loop. Planned is the implementation of a total of three doublets (designation of production + re-injection well).
The development of the geothermal center is planned in the cadaster of Lovča. The annual production of electricity in the first phase will be more than 43-thousand megawatt hours. The total potential capacity of the resource is estimated to be 3-times this size. Residual heat from the power production can be further utilized, in example for district heating supply, in agriculture, industry or for recreational purposes.
Drilling of the geothermal wells
Electricity generation will be possible thanks to the use of hot underground water. The geothermal wells will be located in the southern part of the Žiar basin, as there is a strong indication of potential geothermal reservoirs at depths greater than 3,000 m.
According to the performed surveys and collected data, this location enables it to obtain inflow of geothermal waters with the maximum temperature that is achievable in the geological environment of the pre-Tertiary subsoil of the Žiar basin (140 – 150 ° C). Both geothermal centers are situated within the Lovča concession.
The purpose of the first geothermal doublet within each of the two geothermal centers (Horné Opatovce and Lovča) with an estimated production well depth of 4,000 m is to verify the deep geological structures and geothermal potential of the target areas.
The initial exploration wells will be used as production wells once the parameters and capacity of the geothermal reservoir are confirmed and will be utilized for the long-term exploitation of geothermal water for the production of green electricity.
What is an Organic Rankine Cycle (ORC)?
A condensing cycle for power production which utilizes the hot geothermal water as a heat transfer medium within the primary cycle. It transfers the heat from the primary into the secondary cycle where it heats the working fluid which has a lower boiling point.
The working fluid reaches higher pressure than the water and the produced vapors are led to the steam turbine, where they expand and turn the turbine which rotates and generates electricity.
After the use in the turbine, the steam is condensed into liquid in the condenser and then re-enters the process of being heated up by the geothermal water.
The expected annual use of geothermal water from one production well is expected to be in the amount around 1,749,600 m3 (a total of 10,497,600 m3 from both centers per year), while all exploited geothermal water will be reinjected back to the reservoir after the utilization of its heat without changing its physical-chemical parameters except temperature. Geothermal water will not be discharged into surface streams.
The project is being conducted in cooperation with SSE Holding.
Technical information
6,3 – 6,5 MWe
≈5,4 MWe
43 610 MWh
65 mil. €
Geothermal power plant with two centers with a binary cycle (ORC)
340,000 tons of CO2 / 10 years
(compared to electricity from coal)
197,000 tons of CO2 / 10 years
(compared to electricity from gas)
