Orlík to Become a Giant "Battery": ČEZ Invests 8 Billion Crowns to Modernize the Hydroelectric Plant

The Orlík dam on the Vltava — the largest classic hydroelectric plant in Czechia — is being turned into a giant energy storage facility. According to ČEZ, which is investing 8 billion crowns in the project, the revamped pumped-storage plant will be able to store up to 750 megawatt-hours of energy at once — enough to cover the daily consumption of 80,000 households.

New turbines to replace 1961 equipment

The dam currently runs on four Kaplan turbines dating back to 1961, which harness the flow of the Vltava as it makes its way from the Šumava region to Prague. These will be replaced with more modern Francis turbines, two of which will be reversible.

"Thanks to this modernization, Orlík will gain a bidirectional mode of operation. The plant has been running reliably for 60 years, and the new technology will extend its life by roughly another half-century," said Robert Hečko, director of ČEZ's hydroelectric plants, in comments to journalists.

The reversible turbines will be able not only to generate electricity from flowing water but also to pump it back up from the lower Kamýk reservoir. The plant's total output — 364 megawatts — will remain unchanged, simply redistributed between the standard and reversible turbines. When there's a surplus of electricity in the grid, water will be pumped back up into the Orlík reservoir; when demand rises, the plant will once again release energy into the grid.

Unique turbines tested in Blansko

The reversible Francis turbines will be a world first in engineering terms — massive blade-fitted devices where even the smallest manufacturing error is unacceptable. That's why a scaled-down model is built first and tested for several months in a specialized laboratory. In essence, it works like a miniature dam: instead of a natural body of water, the water sits in a basin beneath the building and is fed to the turbine through a complex system of pipes.

The testing is being carried out by specialists from Litostroj Engineering, whose turbine-model testing lab is located in the town of Blansko. The company has previously taken part in the modernization of the Dlouhé Stráně and Dalešice pumped-storage plants and has also exported its technology abroad — from Scandinavia to the United States, Canada and South America.

The full-size turbine will have a diameter of five meters, while engineers in Blansko are currently working with a model scaled down thirteen times, measuring just 421 millimeters across. Under load testing, the model must withstand the same conditions the real turbine will face in operation. The actual turbine will ultimately be manufactured at Litostroj's plant in Slovenia.

"We run these tests to make sure everything is perfectly fine-tuned. Even before the turbine goes into production, we spend two months of testing checking its key parameters — hydraulic properties, efficiency and operational stability," said Peter Šali, CEO of Litostroj Engineering. According to him, the model will undergo roughly three thousand different measurements.

The active phase of Orlík's modernization is set to begin next year, with completion planned for 2033. The reconstruction will proceed in stages, ensuring that at least two of the four units remain operational at all times.

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Source: novinky.cz