Battery deployment in Southeast Europe is expected to narrow the evening price premium that has made storage a commercial opportunity, changing the returns developers can expect from projects. Bulgaria’s fleet exceeds 19 GWh, making the potential effect on prices a regional issue rather than a theoretical one.
Solar generation depresses prices around midday, while prices rise as solar output falls, demand remains high and flexible generation becomes scarce. In Serbia during August, midday prices were around EUR 66/MWh, while prices averaged roughly EUR 244/MWh around hour 20.
Charging batteries before the evening ramp and discharging them during it can raise the low-price trough and lower the evening peak. The expected outcome is a more stable price profile, though not the elimination of high-price periods.
Weather, hydro conditions, thermal outages, interconnector congestion and demand can still create scarcity events beyond batteries’ response capability. Longer-duration storage may preserve an evening premium later into the night after two-hour battery systems have emptied.
For investors, a narrower average evening premium may change project returns. A project commissioning in 2028 should not be valued using the 2026 evening price curve, and developers are advised to model the assumption that every major neighbouring market will add storage before a project reaches mid-life.
The evening premium remains investable but should be modelled as a declining resource. Batteries are expected to earn less from routine daily cycling and more by selecting the most valuable days, providing balancing services and optimising portfolios.