The Slapy hydropower plant on the Vltava River in the Czech Republic has returned to full capacity after nearly a year, following the completion of a major engineering operation to replace a key safety component on one of its turbine units, CEZ Group has announced.
The TG3 generator set resumed supplying electricity to the grid this week, restoring the plant’s full output and completing the final stage of a broader modernisation programme at the site, which is part of the Vltava cascade of hydropower stations.
The outage was required to replace a 45-ton main inlet valve, a critical safety device that had been in continuous service since the plant began operation in 1955. The new valve was assembled on site from three sections and installed in a shaft more than 40 metres deep.
In addition to the valve replacement, works included repairs to the sealing frame, refurbishment of concrete structures, and an overhaul of the lifting servomotor. The two remaining turbine units had already undergone similar upgrades in previous years.
The return of the third unit follows a wider modernisation of all three 48MW generating units at the plant. The programme, with a reported cost of approximately CZK 500m, has increased efficiency by up to 4% and extended the operational life of the facility by an estimated decade.
With a total installed capacity of 144MW, the Slapy plant plays a key role in balancing the Czech Republic’s power system. It is capable of supplying electricity within 136 seconds of start-up and is primarily dispatched during peak demand periods.
Since entering service, the plant has generated more than 20 billion kWh of electricity. Annual production is sufficient to meet the consumption of more than 40,000 households in the Central Bohemian region.
Slapy is part of the Vltava cascade, a network of hydropower stations developed from the late 1940s along the Czech Republic’s longest river. Across the portfolio, ongoing upgrades to around 40 generating units at more than 20 sites are expected to deliver efficiency gains of 4–10% and support long-term, low-emission electricity generation.
The investments, totalling approximately CZK 5bn to date, are intended to maintain output levels while reducing water consumption and improving operational reliability. Further modernisation projects are planned across the cascade in the coming years.
