ČEZ to construct the Czech Republic’s fourth large pumped storage hydropower plant

The fourth and final generating unit at the Orlík hydropower plant entered operation sixty-three years ago. The plant is now set to undergo the largest modernisation in its history, a transformation that will also make it the fourth major pumped‑storage hydropower plant in the Czech Republic. The pair of reversible Francis turbines will make it possible, when needed, to pump water “one level up” – from the Kamýk reservoir into the Orlík reservoir – thus storing energy for later use. This will make the project a world first, transforming a conventional large hydropower plant into a pumped‑storage facility.

“Our government has set clear priorities for the energy sector. Alongside the development of zero‑emission power generation, these include strong support for energy storage. Our pumped‑storage hydropower plants have delivered decades of reliable operation and continue to play a key role in the stability of the Czech energy system every day. The last pumped‑storage hydropower plant in the Czech Republic was built in the mid‑1990s, and Dlouhé stráně has since become one of the country’s symbols of water‑based energy storage. Today, thirty years later, we are beginning work on a new pumped‑storage facility, and I am confident that the new Orlík installation will serve Czech energy needs reliably and well,” said Minister of Industry and Trade Karel Havlíček.

“Orlík is a key element of the Vltava Cascade and plays an important role in managing the national power system. We have decided that it will continue to serve for decades to come, now also as a large‑scale battery. The elevation difference between the Kamýk and Orlík reservoirs is 70 metres, and we can use this height difference efficiently. One key advantage of this new pumped‑storage plant is that it will be built within the footprint of the existing facility, eliminating the need to occupy additional land. It will therefore be both efficient and environmentally friendly. Another important aspect is that the transformation will be carried out in stages, ensuring that at least two of the four generating units remain in operation throughout the modernisation,” said ČEZ CEO and Chairman of the Board Daniel Beneš.

Engineers will gradually modernise all four generating units at Orlík while maintaining the plant’s total output of 364 MW. An output of 2x95 MW will remain assigned to the conventional one‑way turbines, while the installation of reversible turbines will mean that 2x87 MW will be available for the pumped‑storage mode. The main modernisation phase will begin in 2027, with completion expected in 2033. This will make it possible to store up to 750 MWh of energy in a single cycle, increasing the storage capacity of Czech pumped‑storage plants by over 12%. The more efficient and environmentally friendly plant will strengthen the country’s ability to manage the national power system. ČEZ is coordinating its plans closely with the reservoir’s owner, the Vltava River Basin Authority (Povodí Vltavy).

“We support the Orlík pumped‑storage project and have been engaged in long‑term discussions with ČEZ on its development. For us, it is essential that the plant modernisation and conversion do not require any major structural interventions in the dam itself, nor any changes to the operating water levels defined in the Operating Rules. It is equally important that no land or private property will need to be taken, and the project will not affect recreation, navigation or fishing,” said Petr Kubala, CEO of the Vltava River Basin Authority.

“The Orlík transformation project is clear proof that Czech engineering and technical expertise are world‑class. A project of this complexity can only be implemented thanks to decades of experience in hydropower, an innovative approach and close cooperation among top specialists. We greatly appreciate ČEZ’s trust and are proud to be part of this unique project. The Czech Republic will gain another pumped‑storage hydropower plant capable of storing a quantity of water equivalent to 1,840 Olympic‑size swimming pools, an energy volume comparable to more than one million car batteries,” said Martin Wichterle, Chairman of the Board of Wikov Group.

The Orlík project will be the largest undertaking in the history of modern Czech hydropower. ČEZ has already carried out modernisation work on roughly forty generating units across more than twenty hydropower plants (including Lipno, Dlouhé stráně, Slapy, Kamýk, Mohelno, Dalešice and selected smaller ones). This modernisation has improved the average hydropower unit efficiency by between 4% and 10%, depending on the plant and turbine type. Thanks to investments to date of roughly CZK 5 billion, the hydropower plants are ready for decades of zero‑emission generation of clean electricity, secure supplies for future generations, and the generation of the same amount of electricity from a smaller volume of water. Further hydropower plants are scheduled for modernisation in the coming years.

• Take a live‑like tour of the current Orlík hydropower plant with a virtual walkthrough! https://virtualniprohlidky.cez.cz/cez-orlik/

Martin Schreier, ČEZ Press Officer

 

Did you know that…

• as the largest conventional hydropower plant in the Czech Republic, Orlík has an output of 364 MW, which it can supply to the power system within just 128 seconds of a dispatch command?
• Orlík supplies the grid every year with enough electricity to power tens of thousands of households?
• the output of the three existing large pumped‑storage hydropower plants is controlled by the ČEZ dispatch centre in Prague in cooperation with the transmission system operator, ČEPS?
• the rotating assembly of each generating unit at the Orlík hydropower plant is 27 metres tall and weighs 650 tonnes?
• the heaviest single component – the generator rotor – weighs 400 tonnes?
• during operation at Orlík, each of the four penstocks embedded in the dam, each with a diameter of 6,250 mm, delivers up to 150 m³ of water per second to the turbine at a flow velocity of 5 m/s? And that this stream drives a 50‑tonne turbine runner with a diameter of 5 metres, whose mechanical energy is transmitted via a shaft to the generator rotor?
• each of the four penstocks at the Orlík hydropower plant has a diameter of 6.25 metres, or 1.25 metres more than the tunnels of the Prague Metro?