Contract awarded to equip Mokrice, Slovenia

The Slovenian-based hydropower turbine manufacturer Litostroj Power has announced the signing of a €19 million (US$ 22.7 million) contract with Hidroelektrane Na Spodnji Savi (HESS) for the supply, installation and commissioning of equipment for the 28 MW Mokrice hydropower station on the lower part of the Sava river.

Litostroj Power, a wholly owned subsidiary of independent hydropower producer Energo-Pro, will supply three horizontal bulb units as well as auxiliary systems for the new plant, the company said in a statement on 28 August. Each turbine will have a runner diameter of 4800 mm and rotational speed of 107 rpm, with a nominal power of 9.6 MW at a nominal discharge of 166.7 m3/s and nominal gradient of 6.4 m, and a maximum power of 12.8 MW. The plant is expected to generate average annual production output of 131 GWh under a rated head of 7.47 m.

Mokrice will be the last in a cascade of five plants totalling 187 MW on the Lower Sava, close to Slovenia’s border with Croatia. Litostroj Power said it had supplied equipment for the first four plants in the cascade: Boštanj, Arto-Blanca, Krško, and Brežice. Plans to develop Mokrice were delayed after a local court ordered a review in 2019 of the environmental permit that was awarded in 2018 to the owner-operator, a subsidiary of the state-owned national power producer GEN-Energija. Construction of the combined run-of-river and storage facility had been scheduled to begin in 2019 for commissioning in 2023. “The design of the new hydropower station was adjusted several times to meet all the demanding conditions for a fully ecological operation without any adverse impact on the ecosystems of the Sava and Krka rivers,” Litostroj Power said.

Work on the design and technical documentation for the prototype units is underway at the hydraulic laboratory of Litostroj Engineering in Blansko, Czech Republic, with the performance of the turbines needing to be first confirmed by a model test before manufacturing can begin. Litostroj Power has 50 months to fulfil the contract, including installation and testing of the equipment.