ČEZ and Litostroj Engineering have begun testing a model of the reversible Francis turbine that will be used to convert two units at the Orlík hydropower plant in the Czech Republic to pumped storage operation.
The work forms part of a CZK8bn (€330m) modernisation programme that will convert half of the 364MW plant’s generating capacity to bidirectional operation. Completion is scheduled for 2033.
Testing is taking place at Litostroj Engineering’s Hydraulic Laboratory in Blansko, South Moravia, ahead of manufacture of the full-scale turbines.
A 1:13 scale turbine model, with a diameter of 421mm, has been installed on a hydraulic test circuit to simulate the operating conditions expected at Orlík. The full-scale turbine will have a diameter of approximately 5m.
Litostroj said the two-month testing programme will examine hydraulic characteristics, efficiency and operational stability, with up to 3000 measurements expected to be carried out. The results will be used to confirm specifications for manufacture of the full-scale equipment.
“Everything must be perfectly aligned. One of the most important parts of the new power plant is the reverse Francis turbine. Before we manufacture it, we must verify its key parameters in detail during two months of testing, such as mainly hydraulic properties, efficiency or operational stability,” said Peter Šály, CEO of Litostroj Engineering. “Step by step, we can perform up to three thousand measurements. Based on them, we will then confirm the specifications for the production of the real turbine so that we achieve the optimal solution, including maximum performance.”
Under the Orlík modernisation programme, all four existing units will be upgraded while the plant’s overall installed capacity will remain at 364MW. Two units will retain conventional generating operation with a combined capacity of 190MW, while two 87MW reversible units will provide 174MW of pumped storage capacity.
The new units will pump water from the lower Kamýk reservoir back into Orlík reservoir during periods of surplus electricity supply. ČEZ estimates the arrangement will provide storage capacity of up to 750MWh, allowing the plant to return stored energy to the Czech power system during periods of higher demand.
The main phase of the modernisation is due to begin in 2027 and is scheduled for completion in 2033. Work will be phased so that at least two of Orlík’s four units remain operational throughout the programme.
ČEZ is coordinating the project with dam owner Povodí Vltava. According to the company, the conversion will not require major structural interventions to the dam or changes to its defined operating water levels.
Orlík has been in operation for more than 60 years and is the Czech Republic’s largest conventional hydropower plant. The project represents the largest construction programme undertaken in the Czech hydropower sector for around 30 years.
ČEZ has previously modernised approximately 40 turbines at more than 20 hydropower plants, including Lipno, Dlouhé Stráně, Slapy, Kamýk, Mohelno and Dalešice. The company said around CZK5bn has so far been invested in its wider hydropower modernisation programme.
Litostroj Engineering has also previously been involved in projects at the Dlouhé Stráně and Dalešice pumped storage plants.
