Week 23 in Southeast Europe was marked by higher electricity demand alongside weaker variable renewable output. Regional demand rose 8.2% week on week to 15.15 TWh. Variable renewables fell 8.9%, with wind down 15.5% and solar down 5.1%. At the same time, thermal generation increased 24.5% to 4.22 TWh.
Imports also moved higher during the same period. Net imports rose 9.1% to 1.22 TWh. Hourly pricing followed a pattern described as lower daytime levels followed by a steep evening ramp across most SEE markets.
Week 23 generation mix and the evening price pattern
The combination of rising demand and declining wind and solar output coincided with increased thermal dispatch. Thermal generation growth and higher net imports were cited as the response to weaker renewables during Week 23. The hourly price profile showed prices climbing sharply into the evening peak across most markets in the region.
This market shape is linked to how battery systems can operate across the day-night cycle. Batteries can charge during lower-price daylight hours when solar output depresses prices, then discharge during evening hours when solar fades. With demand remaining high into the evening, thermal units set the marginal price in the described profile.
Implications for solar and wind project revenue profiles
The changing intraday price environment affects how solar projects capture value over their production window. A standalone solar plant may face lower realised prices during periods when more PV is added to the system. In contrast, a solar-plus-storage configuration can shift part of generation into higher-value hours.
Storage paired with solar was also described as a way to reduce curtailment exposure and support PPA delivery under the same market conditions. For wind developers, batteries were linked to managing forecast errors and imbalance costs, along with handling short-duration output variability.
BESS use cases across SEE markets
The early BESS investment cases were described as strongest where solar penetration is rising and evening spreads are volatile, alongside limited flexible capacity. Greece, Bulgaria, Romania, Hungary, Serbia and Croatia were listed as fitting parts of that profile. Two-hour and four-hour battery durations were referenced for those markets.
In those settings, batteries were associated with merchant arbitrage opportunities as well as participation in ancillary services, congestion management and balancing support. The same operational flexibility was also positioned as relevant to managing system needs during periods when renewables weaken.
Bankability considerations and system-level role
Batteries were also described in terms of financing requirements rather than only technical performance. Lenders increasingly seek revenue resilience in addition to expected generation output for BESS projects. A battery can reduce exposure to low-price hours and improve shape risk while supporting firmed delivery.
For merchant projects, the revenue stack was described as spanning day-ahead, intraday and balancing markets. Week 23 was cited as an example of batteries functioning as system assets: higher demand and weaker renewables led to greater thermal dispatch and increased imports, while storage could reduce reliance on expensive evening thermal generation, limit import dependence and improve grid flexibility.
