Croatia had about 220 hours of negative electricity prices in the first half of 2026, as renewable growth increases power-market volatility and the commercial relevance of batteries. Negative prices indicate that generation is arriving faster than the power system can shift or absorb it.
AdriaFlex is seeking partners for standalone battery projects totalling 170 MW across three sites. The developer is also working on an 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. Wind and solar account for 44% of Croatia’s installed capacity.
Separately, wpd plans to repower Croatia’s Trtar Krtolin wind farm, which currently has a capacity of 11.2 MW, to as much as 30 MW using fewer, larger turbines. The project is expected to lift annual output from around 30 GWh to about 55 GWh and add a 10 MW battery.
The repowering would turn Trtar Krtolin from a generation-only asset into a hybrid project intended to focus on market value as well as output. Croatia is an early Southeast European example of storage economics shifting from reliance on policy support towards merchant optimisation.
The commercial question is how quickly batteries can earn revenue from intraday spreads, charging during negative-price periods, balancing and congestion before competition compresses returns. Storage revenues are expected to depend increasingly on combining arbitrage, balancing and grid services rather than relying on a single contracted income stream.
