Reduced production at Slovenia’s Krško nuclear power plant is costing GEN Energija at least EUR 300,000 per day, as the company turns to the wholesale electricity market to replace generation that had already been sold under forward contracts.
GEN Energija had sold most of Krško’s expected 2026 electricity production in advance. With the nuclear plant generating below planned levels, the company must now purchase replacement electricity to meet those contractual obligations. Wholesale prices have averaged around EUR 180/MWh, while evening prices have climbed significantly higher as regional supply conditions tighten.
The production shortfall is also increasing reliance on the Brestanica gas-fired power plant, which is normally used primarily as a system reserve. Higher electricity prices have nevertheless made its operation commercially viable despite elevated gas and carbon costs, with evening market prices recently reaching EUR 300–400/MWh.
As a result, Brestanica has already exceeded its expected full-year generation target well before the end of 2026. The plant produced 25.75 GWh by 5 August, around 3% more than its planned generation for the entire year.
The situation highlights the financial exposure created when a large baseload plant operates below expectations after its output has already been sold forward. GEN Energija is effectively facing the difference between the price at which Krško’s electricity was contracted and the considerably higher cost of securing replacement power on the wholesale market.
At the same time, increased operation of Brestanica is providing additional domestic generation during periods of tight regional supply, but at a significantly higher marginal cost than nuclear production.
The combination of lower nuclear output, costly replacement purchases and increased gas-fired generation is therefore putting additional pressure on GEN Energija’s finances at a time when Southeast European electricity prices remain elevated, particularly during evening peak periods.
