Southeast Europe’s rapidly expanding renewable fleet is starting to move from passive day-ahead generation into intraday and balancing markets. That shift increases the value of batteries, aggregation and more accurate forecasting. Solar and wind output contributed to some of the region’s largest price swings this summer.
When actual generation differs from day-ahead schedules, those price swings create balancing requirements. The resulting deviations generate costs for generators while also creating revenue opportunities for flexible assets.
Integrated European balancing and easing flexibility access
Europe’s balancing market is becoming increasingly integrated through common platforms. At the same time, regulators are gradually lowering barriers for batteries, aggregators and smaller flexibility providers. This environment affects how flexible resources can participate alongside growing renewable volumes.
As participation expands, the role of batteries extends beyond earlier market entry points. Four-hour batteries are beginning to replace an earlier focus on one- and two-hour projects.
Romania’s BESS buildout and regulatory approvals
Romania is emerging as a regional test market for these developments. Its operating BESS fleet has passed 1 GW, with energy capacity above 2.3 GWh. Hundreds of additional megawatts have received regulatory approvals.
The operating scale in Romania aligns with a shift in how revenue is generated from storage. Early batteries could rely heavily on frequency and balancing services, reflecting the initial emphasis on those products.
Changing revenue models for storage and renewable portfolios
As competition increases, developers are expected to combine balancing revenue with day-ahead and intraday arbitrage. That mix also includes renewable optimisation and congestion management. The change in available revenue streams affects how projects are structured for market participation.
Renewable generators face a different set of pressures as their market share grows. Projects that remain poorly forecast or unable to rebalance positions close to delivery will face increasing imbalance exposure.
Contracting shifts as real-time trading value rises
This dynamic is expected to encourage solar and wind producers to contract with aggregators, traders and BESS operators rather than sell fixed production profiles. Autumn is set to accelerate the shift as more variable wind generation and rapidly changing solar ramps increase the value of trading closer to real time.
The next stage of SEE renewable integration will be determined less by how much renewable capacity is connected. It will instead depend on how efficiently that capacity is forecast, traded and balanced across intraday and balancing processes.
