2025 was a year of breaking records in Slovenské elektrárne. In the position of the largest electricity producer in Slovakia, Slovenské elektrárne produced 21,013 GWh of electricity free of direct CO2 emissions in 2025 (after having deducted the station service consumption, the company supplied 18,804 GWh to the grid). For illustration, production of 21,013 GWh of electricity free of emissions would be sufficient for 1.75 to 3 million households, if we take into account a standard Slovak household with electrical heating.
Nuclear power plants comprised the key pillar of Slovenské elektrárne’s portfolio: thanks to the high availability of the units and reduced outage durations (i.e. the scheduled “technical review” of the reactor in order to carry out important inspections, refuelling, and maintenance) they achieved the highest supply in their history. At the same time, the company has been using its pumped storage power plants to compensate for the effects of the drought and made use of the market price signals.
The five nuclear units demonstrated high level of stability. Slovenské elektrárne preveted enforced outages and had less total outage days than in 2024, which was reflected in better generation results. The company actually achieved 17,930 GWh of emission-free electricity from the nuclear with five operated units, which would be enough for approximately 1.5 to 2.6 million Slovak households. This is a new record!
“With respect to the operation, 2025 was a successful year for the nuclear power plants. We managed to keep the units at slightly higher power than planned. Colder summer helped us too, so we usually did not need to reduce power as we had to during the previous hot summers,”
Ján Mazánik, Manager of the Trade in Regulating Services and Resource Employment
The final quarter of last year further increased our performance. The shortest general outage in the history of unit 2 at Mochovce (17.97 days) helped significantly. In December 2025, we supplied 1,711,769 MWh from the nuclear sector, which is the highest production for one month in the history of our nuclear power plants.
Slovenské elektrárne hydro power plants produced 1,691 GWh last year. The beginning of the year brought low levels in the Liptovská Mara and Orava reservoirs, which struggled with exceptional drought for almost three seasons. This resulted in the lowest supply from the run-of-river power plants in the history – 1,085 GWh. The autumn rains mitigated the impact but they could not change the trend of the year.
Slovenské elektrárne partially compensated for the unfavourable weather conditions with the pumped storage power plants, which were employed significantly more than planned. They produced 582 GWh (plan 377 GWh) with the consumption for pumping at almost 774 GWh (plan 512 GWh).
“Many times at noon with surplus of energy from solar plants, the electricity price was decreasing to zero and sometimes even to negative values, while the morning and evening peaks brought high prices. This was an ideal profile for pump operation when the electricity was cheap and turbine operation during peaks”, Ján Mazánik explained.
In 2025, the company employed the pumped storage power plants the most in the history of more than 20 years since they have been managed by the Slovenské elektrárne dispatching.
2025 brought the most trading periods with negative prices in history. This is the direct effect of the fast growth of the installed capacity from unpredictable renewables in the interconnected European grid. For this reason, the character of the daily market changed from hourly to 15‑minute trading as of October 2025. A shorter product reflects the real situation better and brings higher price differences between 15-minute intervals.
According to J. Mazánik, the volatility will be emphasised even further and the price differences between the 15-minute intervals will grow even more. In order to make better use of the flexibility on the changing market in trading, the company is preparing some adjustments in the operation of the hydro power plants within the Váh River Cascade to 15‑minute mode.
In addition, the portfolio of Slovenské elektrárne will be enriched by the battery energy storage system at Nováky this year. There will be two systems with the output of 36 MW and capacity of 72 MWh. These are now going through energy tests with the dispatching. Their commissioning is scheduled for March 2026. The batteries will complement the pumped storage power plants and improve our response to fast price volatility.
Experience from the last year can serve the company as a well-proven recipe for the following season: stable generation at nuclear, flexible pumped storage power plants, and intelligent profit from intraday opportunities. In addition, the Nováky BESS and technological readiness for 15-minute trading will be added to the energy portfolio of Slovenské elektrárne.
With more than 70% share in the overall electricity generation in Slovakia, Slovenské elektrárne, a.s. is the largest electricity producer in the country. After having shut down the last coal power plant at the end of the first quarter of 2024, it generates all electricity free of direct CO2 emissions. It operates 5 nuclear units, 31 hydro power plants, and 2 photovoltaic plants.
The Company’s commitment to generate electricity from low-carbon sources makes it the leader in sustainable energy generation in the Central and Eastern Europe. The company has been included in the prestigious Europe's Climate Leaders index, which The Financial Times and Statista have been producing since 2021, four times.
Slovenské elektrárne, a.s. has two shareholders. Slovak Power Holding B.V. (SPH) owned by a Czech energy group Energetický a průmyslový holding (EPH) is the majority shareholder with a 66% share. The second shareholder is the Slovak Republic holding 34% of the company.
