IN Brief:
- ČEZ plans to convert part of the Orlík hydropower station into pumped storage.
- The pumped-storage element will total 174MW/750MWh with around 4.3 hours of duration.
- The project shows how existing hydro infrastructure can be adapted for flexibility rather than only generation.
ČEZ Group is preparing to convert part of the Orlík hydropower station in the Czech Republic into a pumped-storage asset, creating 174MW/750MWh of storage capacity within an existing hydro complex.
The project will be delivered in partnership with Wikov Group, while the Vltava River Basin Company owns the plant. The plan involves modernising all four hydropower turbines at Orlík and converting two of the units into reversible pumped-storage machines.
Two 95MW units will remain conventional unidirectional turbines. Two 87MW units will be converted into reversible pumped hydro energy storage units through the installation of reverse Francis turbines. The overall plant will retain its existing 364MW power capacity, while the new pumped-storage element will provide a duration of about 4.3 hours.
Construction is planned to start in 2027, with completion expected in 2033. By using the height difference between Orlík Lake and the lower Kamýcké Lake, the scheme can add storage capability without creating an entirely new reservoir system.
The conversion would become the Czech Republic’s fourth pumped hydro plant, joining Dlouhé Stráně, Dalešice, and Štěchovice. It also extends ČEZ’s wider hydro modernisation activity, which has included around 40 turbine upgrades across 20 Czech hydropower plants.
Pumped hydro remains the largest established form of grid-scale electricity storage globally, although new projects can be difficult to deliver because they require suitable geography, substantial civil works, long permitting periods, and public acceptance. Converting existing hydro assets can reduce some of those barriers, even where complex mechanical, civil, electrical, and environmental engineering remains unavoidable.
The Orlík plan shifts part of an existing generation asset into a more flexible operating role. Rather than only producing electricity from natural water flows, reversible units can consume electricity to move water uphill when power is abundant, then generate electricity when demand, prices, or system needs increase.
That role becomes more valuable as renewable generation grows. Solar-heavy systems can experience midday surpluses, while wind output can fluctuate over longer periods. Pumped storage can provide a large, synchronous, mechanically robust form of flexibility, complementing battery assets that offer faster response but usually shorter duration.
The contrast with battery storage is instructive. Planning concerns around battery energy storage systems often centre on safety, land use, emergency response, cybersecurity, noise, and community acceptance. Pumped hydro faces a different set of constraints, with civil engineering, hydrology, water management, environmental assessment, and long construction programmes carrying greater weight.
The two technologies are not interchangeable. Batteries can be installed close to substations, renewable projects, load centres, or constrained network areas, and can respond rapidly to grid signals. Pumped storage generally requires specific geography but can provide durable, large-scale storage over longer asset lives. A renewable-heavy grid is likely to require both fast-response assets and longer-duration flexibility.
The Orlík conversion also underlines a wider European trend: existing infrastructure is being re-examined for its flexibility value. Hydropower stations, substations, industrial sites, salt caverns, data-centre connections, rail power systems, and commercial loads are all becoming candidates for more active participation in balancing and grid management.
The long delivery schedule reinforces the construction reality behind system flexibility. Assets needed in the 2030s must be designed, consented, financed, and procured years earlier, particularly where heavy engineering and network interfaces are involved. Hydro conversions may avoid some greenfield challenges, but they still sit on infrastructure timelines rather than consumer-technology timelines.
Further information on ČEZ’s power generation activities is available through ČEZ Group.
