Slovenia’s last coal mine turning to green energy, underground farming

Slovenian firm HTZ from Velenje, subsidiary of lignite producer Premogovnik Velenje, is the contractor in a challenging solar power project. The country’s last coal mine is exploring options for methane extraction, a gravity power plant, underground energy storage and farming.

The last lignite complex in Slovenia has one decade to come up with solutions for the future as the country may abandon the use of the fossil fuel in 2033. Premogovnik Velenje, the operator of the coal mine that supplies the struggling thermal power plant Šoštanj – TEŠ, joined nine research and innovation projects cofunded by the European Union’s Research Fund for Coal and Steel (RFCS).

Separately, the state-owned company’s subsidiary HTZ began the construction of a 2.6 MW solar power plant next to the drain canal of hydropower plant Zlatoličje in Slovenia’s northeast. As the contractor, it is also responsible for the design and commissioning of the unit, part of a 30 MW project.

HTZ Velenje switches to larger solar power projects

The segment is envisaged to have a peak capacity of 2.7 MW. Premogovnik Velenje said its firm has “an extremely demanding task” due to the 30-degree slope and the proximity of the water. The solar power unit’s planned annual output is 3 GWh. It will be 905 meters long.

HTZ Velenje took a loan to partly finance the project, valued at EUR 2 million, which it expects to complete by the end of the year and connect it to the grid in the first quarter. The firm already built 13 small ground-mounted and rooftop photovoltaic plants of 4.2 MW in total, of which one is at Zlatoličje. It is currently also working on a 3 MW solar power plant in Prapretno, on a rehabilitated fly ash and gypsum landfill.

Underground coal mine may be suitable for methane production, smart farming

The RFCS projects will be implemented with partners from seven European countries including Greece and Romania. One of them, Gravpower 2.0, is for a power plant that would use gravitational energy with a smart system for energy storage management, Premogovnik Velenje said. The mine has depth of up to 500 meters.

Of note, Slovenia recently adopted a renewables promotion law and it has various schemes for supporting green energy production.

The company will analyze the technical capabilities of its underground coal mine to host an energy storage system after closure. It will also work on the possibility to extract methane and contribute to a sustainable, hydrogen-based economy. Another possible use for the abandoned underground galleries will be smart farming, covered by a project called Mine4Food.

Premogovnik Velenje is working on a gravitational power plant concept for smart energy storage

Premogovnik Velenje said it would promote coal mining as European cultural heritage and improve job mobility and green job creation in line with the European Green Deal and the fair transition principle.

On the environmental protection front, there are projects for remediation and mining waste processing, both with long-term monitoring. Premogovnik Velenje revealed it obtained more than EUR 2 million so far from the fund and said it expects some revenue from earlier endeavors within the RFCS program.