Renalfa IPP has expanded its Devnya solar plant in Bulgaria from 5 MWp to 65 MWp and paired the site with a 60 MW/165 MWh battery. The upgrade increases photovoltaic capacity at the location by roughly thirteenfold. It also adds about 2.75 hours of battery storage at full output.
The Devnya project reflects a shift in Bulgaria’s renewable buildout toward hybridising existing grid-connected assets. Instead of relying only on new solar construction, developers are combining additional generation with storage at sites already connected to the grid. This approach is linked to the growing value of grid access in Southeast European renewable markets.
Hybridisation using existing grid-connected generation
A project with an existing connection can potentially expand faster than developments waiting for new capacity in connection queues. The Devnya upgrade illustrates how developers can increase output while adding storage functionality to an established site.
Bulgaria’s market conditions also shape the commercial case for hybrid projects. The country has seen increasingly frequent periods of very low or negative electricity prices during strong solar production. For Sept. 20 delivery, Bulgarian prices fell slightly below zero during several midday intervals before rising to more than €240/MWh in the evening.
Battery storage aligned with intraday price patterns
In that price environment, storage can be used to hold solar generation during lower-priced hours and discharge later when prices rise. Renalfa has said the Devnya configuration allows part of the solar output to be stored rather than sold during weaker-priced intervals.
The company also stated that the setup supports more stable green electricity products. Renalfa said this moves the project closer to supplying shaped or baseload-like renewable power compared with purely intermittent solar generation.
Grid connection utilisation and infrastructure value
Hybridisation can also change how a site uses its grid connection over time. A conventional solar plant may rely on its connection heavily for only part of the day. Adding batteries enables electricity delivery across more hours using the same connection.
As grid capacity becomes scarce, that optimisation can become a key economic factor for colocated storage at existing renewable sites. Bulgaria’s first solar boom focused on adding photovoltaic megawatts quickly, while the emerging second phase is described as extracting more value from those megawatts through upgrades like Devnya’s transformation from a 5 MW site into a 65 MWp generation and 165 MWh storage platform.
