Kořensko Hydro Plant Promises Greater Efficiency and Climate Resilience

Kořensko hydroelectric power plant is currently undergoing the largest modernization in its 34-year history. Operated by ČEZ as part of the Vltava cascade, the multi-million-crown overhaul will replace core machinery across both of its turbine units, resulting in safer, greener, and significantly more efficient operations by next spring.

Located near the Temelín Nuclear Power Plant, the 3.8-megawatt facility processes the Vltava River’s natural flow just below its confluence with the Lužnice River. The extensive modernization project, backed in part by subsidies from the TAK Operational Programme (Technology and Applications for Competitiveness), began last spring with the dismantling of the first turbine set (TG1). Engineers are currently on-site installing new main components, including a state-of-the-art turbine impeller and generator. In August, the plant’s second unit (TG2) will be temporarily taken offline to install a unified control system and upgrade the 6 kV substation. Once TG1 passes its tests and returns to full operation in September, crews will immediately begin the complete teardown and modernization of TG2. “In this modernization, worth over one hundred million crowns, we are replacing turbines and installing new generators and control systems,” said Róbert Heczko, Director of ČEZ Hydropower Plants. “The operation of the power plant will be more environmentally friendly, but above all, more efficient. The power units will be able to use half the flow rates compared to today.”

The Kořensko upgrade is part of a massive, 15-year comprehensive modernization project by ČEZ to revamp the Czech Republic’s hydropower infrastructure. Over the last decade and a half, the energy giant has invested more than 4.5 billion crowns to upgrade turbines at over 20 hydroelectric plants, including major sites like Lipno, Dlouhé stráně, and Slapy. Together, the repaired plants have a total output of over 1,400 MW—roughly three-quarters of the output of the Dukovany nuclear power plant.

“The Vltava Cascade power plants are a key element of the Czech hydropower industry, with a significant role in managing the entire energy system,” explained Pavel Šleška, Director of the ČEZ Conventional Energy Division. “In recent years, we have invested over 1.5 billion crowns in their renovation, modernizing more than half of the Vltava units. After completing work on Kořensko and Lipno II, we will finish the renovation of Hněvkovice and move on to modernize the large Štěchovice and Orlík plants.”

The environmental and economic impact of these investments is growing. The modernizations increase average plant efficiency by up to 5%, which extends the lifespan of the facilities by decades.

More importantly, the new technology addresses the increasingly uncertain climatic conditions and frequent droughts in the region. By allowing the turbines to operate on significantly lower water volumes, the modernized cascade secures reliable, emission-free electricity for hundreds of thousands of households, regardless of shifting weather patterns.

Hydropower Modernization and Grid Resilience at Go Net Zero

The extensive modernization of existing hydroelectric assets, efficiency optimization through advanced turbine technology, and strategies for maintaining renewable generation under changing climate and low-flow conditions will be key topics of discussion at next year’s Go Net Zero Energy- Central and Eastern Europe Summit.