Slovenia's pilot geothermal power station, tapping into an abandoned wellbore in the Lendava area, has produced the first kilowatts of electricity but tests have shown that modifications will be required for viable long-term energy generation.

Located at an abandoned natural gas well in Čentiba in the northeast of the country, the facility is run by DEM, the company operating hydro power stations on the river Drava which is part of the state-owned group HSE.

DEM started working on the roughly 3,000 metres-deep Pg-8 wellbore in 2022.

The €1.2 million project is meant to generate about 400 megawatt hours of electricity a year and pave the way for zero carbon geothermal energy extraction at a number of other disused gas wells in the country and abroad.

The first tests, which got delayed a bit due to extensive well-renewal procedures, have confirmed the capacity for generating energy, but DEM said on 16 April that modifications will be needed for permanent use.

"The thermal capacity of the well has proved to be insufficient to provide the necessary ammonia vapour flow to operate the 50-kilowatt pilot plant on a sustained basis," DEM explained, announcing a modification of the turbine section.

The idea behind the plant, a product of Slovenian know-how, is to tap into the existing wellbore to extract geothermal energy rather than gas in what is a closed-loop system where the liquid refrigerant (ammonia) does not come into contact with the overheated rock.

DEM announced the project at the beginning of 2021 and received a building permit in May 2022. The company Petrol Geo, one of the partners in the project, started underground works in December 2022.