Southeast Europe is entering the 2026-27 winter with a growing shortage of power-system flexibility, as grids, storage and dispatchable capacity fail to keep pace with a more volatile system. The constraint is not a lack of generation projects, but the limited capacity to integrate output, balance the system and move electricity when needed.
Country pressures include heavy electricity imports in Serbia after weak hydro output, Kosovo’s loss of a 260 MW lignite unit, and Romania’s extension of an energy emergency while nuclear capacity is unavailable. Croatia recorded roughly 220 hours of negative electricity prices in the first half of 2026 and is beginning to price the value of batteries.
Bulgaria has moved faster on storage than the Western Balkans. IENE cites operating battery capacity of 6.23 GW and more than 19 GWh in Bulgaria, alongside 7.3 GW of solar capacity. The country is seeking to turn solar oversupply and intraday volatility into dispatchable value through storage.
New debt financing for the 246 MW, 512.5 MWh Tenevo battery project reinforces a shift from grant-supported deployment towards bankable infrastructure. The project’s financing comes as Bulgaria’s storage build-out contrasts with slower progress elsewhere in the region.
Montenegro is announcing partnerships covering solar, wind and battery energy storage systems, while Croatia is assembling portfolios of standalone and co-located storage. North Macedonia has started auctioning guarantees of origin, but grid capacity, permitting, financing and market depth remain constraints on development.
The region is moving at two speeds, with projects multiplying faster than the institutions and flexibility assets needed to integrate them. Power-market value is shifting from installed megawatts alone towards capacity that can shift, store or balance electricity, or move it across borders.
Batteries, pumped storage, transmission, interconnectors and dispatchable supply are identified as the strongest investment theme in Southeast Europe. The growing value of flexibility also favors pumped hydro and flexible gas assets; systems reliant on ageing thermal units or weather-sensitive hydro without sufficient balancing capacity face higher costs.
