Renalfa has expanded its Devnya solar plant in Bulgaria from 5 MWp to 65 MWp and added a 60 MW/165 MWh battery. The upgrade turns the site into a hybrid asset combining solar generation and electricity storage. Renalfa said the change increases the value of the site’s existing grid connection. The project reflects a shift in Bulgaria’s renewable development toward adding storage alongside generation.
Expanding capacity on an existing grid-connected site
The Devnya upgrade multiplies photovoltaic capacity by roughly thirteenfold. It also adds about 2.75 hours of battery storage at full output. Developers are increasingly using existing grid-connected locations to add more generation and pair it with storage rather than building new solar projects only. This approach is linked to the growing importance of grid access in Southeast European renewable markets.
A project that already has a connection can potentially move through expansion faster than developments waiting for new capacity in connection queues. In that context, hybridisation can change how much electricity a site can deliver across different hours. The Devnya configuration illustrates this transition by converting an earlier 5 MW solar installation into a 65 MWp generation and 165 MWh storage platform.
Battery storage aligned with Bulgaria’s price patterns
Bulgaria has seen more frequent periods of very low or negative electricity prices during periods of strong solar output. For Sept. 20 delivery, prices fell slightly below zero during several midday intervals before rising to more than €240/MWh in the evening. Storage can shift when solar electricity is sold by holding output during lower-priced hours and discharging later when market conditions tighten. That operational profile is designed to capture value from intraday price swings.
Renalfa said the hybrid configuration also supports more stable green electricity products. The company described this as moving the project closer to supplying shaped or baseload-like renewable power rather than purely intermittent solar generation. Such characteristics can be relevant for corporate buyers seeking predictable supply profiles. Industrial consumers often prefer electricity delivery patterns that are not tied entirely to sunshine.
Using grid capacity across more hours
Hybridisation can improve utilisation of transmission and distribution infrastructure connected to a site. A conventional solar plant may rely on its grid connection heavily only during part of the day, depending on production profiles. Adding batteries allows the same connection to carry electricity across a wider set of hours. As grid capacity becomes scarce, that ability to optimise flows can become a key economic factor for colocated storage.
