/SOFIA, BULGARIA, October 5, 2026, 9:00 CEST, RENEWABLE MARKET WATCH™/ A tender has been launched to build a second reservoir at the ‘Chaira’ pumped-storage hydropower plant and a connecting tunnel, with the investment estimated at €350 million excluding VAT. This is €100 million more than the initial estimate of €250 million.
The project includes the new ‘Yadenitsa’ reservoir (dam) and a tunnel over 6 kilometres long, which will connect it to the existing ‘Chaira’ reservoir. The aim is to increase the water volume available to the pumped-storage power station from 4.2 million cubic metres to 13.4 million cubic metres.
More water for longer plant operation
The increased water volume should enable the ‘Chaira’ pumped-storage power station to operate for longer, with greater flexibility and improved efficiency. The ultimate aim is for the plant to operate round the clock. The ‘Chaira’ pumped-storage power station is part of the National Electricity Company’s ‘Belmeken – Sestrimo – Chaira’ hydropower complex. Its rated capacity in pumping mode is 784 MW, whilst in electricity generation mode it reaches 864 MW.
Tender applications must be submitted by 4 November
Tender applications must be submitted by 4 November. The successful contractor will be required to complete the construction within 60 months. Funding is expected to be provided from the state budget and European funds. Earlier this year, the European Union included ‘Yadenitsa’ on its list of projects of common interest, opening the possibility of EU co-financing.
A project halted in the 1990s
The idea for the “Yadenitsa” dam was first mooted in 1994 but was later halted because of funding issues and concerns about seismic risk. The project was updated in 2016 and 2017, and work on it resumed in 2022. The ‘Chaira’ pumped-storage power station itself was shut down in 2022. Since then, NEC has recommissioned two units and has begun repairs on a third. Two other pumped-storage power stations operate in the country: ‘Orpheus’ and ‘Belmeken’.
Bulgaria has also identified ten suitable sites for new pumped-storage capacity, including Dospat, Batak and ‘Chaira 2’. Developing energy storage facilities is one of NEK’s priorities and a priority in the country’s energy policy.
For more information and answers to your questions about the Bulgarian energy storage market and related content, you may read here: Bulgaria Battery Energy Storage System (BESS) Market Outlook 2026 – 2035
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