Croatia’s renewable build-out is sharpening the commercial case for battery storage after the country recorded about 220 hours of negative electricity prices during the first half of 2026. Wind and solar account for 44% of installed capacity, increasing the need to shift or absorb generation when supply arrives faster than the power system can handle it.
Developer AdriaFlex is seeking partners for a 170 MW portfolio of standalone battery projects across three sites. It is also developing an additional early-stage battery energy storage system pipeline of around 200 MW, and is targeting ready-to-build status for its projects in the fourth quarter of 2028.
Negative prices indicate that generation is outpacing the system’s ability to shift or absorb electricity. For batteries, the commercial question is how quickly they can earn revenue from intraday spreads, charging during negative-price periods, balancing and congestion before competition compresses returns.
Separately, developer wpd plans to repower Croatia’s Trtar Krtolin wind farm, which currently has a capacity of 11.2 MW, and add a 10 MW battery. The plan would use fewer, larger turbines to lift capacity to as much as 30 MW and increase annual output from around 30 GWh to about 55 GWh.
The repowering and battery addition would turn the wind farm from a generation-only asset into a hybrid project focused on market value as well as output. Croatia is an early Southeast European example of storage economics shifting from reliance on policy support toward merchant optimisation. Storage revenues are expected to depend increasingly on combining arbitrage, balancing and grid services rather than relying on a single contracted income stream.