South East Europe’s electricity market is entering a new phase as the region’s outlook moves beyond the aftershocks of the 2021–2022 energy crisis, imported gas costs and coal availability. Those drivers remain relevant, but the structural issue highlighted in recent analysis is flexibility. The market question is shifting from whether there is enough power to whether the system has the right supply at the right hour. This change is linked to price formation, investment decisions and security of supply.
The clearest signal cited for this shift came from summer 2024 price spikes. ACER found that most Southeast European bidding zones saw significant price increases during that period, especially in evening hours, with prices reaching up to €1,000/MWh in some cases. ACER also concluded that the spikes were not only a fuel-price event. The agency linked them to a lack of flexible resources able to replace solar generation after sunset, together with limited cross-border capacity to import cheaper power from other regions.
Hourly balance and the limits of annual baseload pricing
The analysis points to an exposure to the gap between daytime renewable output and evening demand. South East Europe has strong renewable-resource potential, particularly solar, alongside legacy hydro, coal and gas assets that can provide firm supply under certain conditions. However, the problem described is increasingly hourly rather than based on total annual generation. The emphasis is on whether supply can meet demand within specific time intervals.
Average baseload prices are described as becoming less useful as an indicator under these conditions. A system can appear adequately supplied on an annual basis while still experiencing severe price stress during a small number of evening hours. The same pattern is described for midday periods during high solar output, when prices can be very low or negative while scarcity pricing emerges later. For utilities, traders, renewable developers and industrial consumers, the value of electricity is moving from the megawatt-hour alone to the timestamp attached to it.
Persistent price separation between Southeast and Central Europe
A further indicator cited is the price gap between South East Europe and Central Europe. ACER reported that while 2025 prices did not reach the extreme levels seen in summer 2024, the price gap between Southeast and Central Europe persisted throughout 2025 and into early 2026. The report is presented as evidence that volatility is structural rather than accidental. The same framework connects this separation to differences in how flexibility and cross-border flows operate across regions.
Three factors are listed as explaining structural volatility in South East Europe’s power markets. First, solar growth is described as outpacing system flexibility requirements. Solar lowers prices during daylight hours, especially at midday, but does not address evening peak demand on its own.
Flexibility requirements: solar growth, grid constraints and integration
The first factor is tied to the absence or limited availability of batteries, pumped hydro, flexible gas, demand response and stronger interconnectors. Without these resources, the system can be long during daylight hours and tight after sunset. The second factor highlighted is that grid constraints affect outcomes as much as generation mix. When lower-cost electricity cannot move into the region when needed, local prices separate.
This second factor links market outcomes to cross-border capacity, market coupling and transmission investment. The third factor cited is uneven integration across the region’s markets. EU member states in South East Europe operate within the EU electricity-market framework, while Western Balkan markets are still progressing toward full integration. Serbia’s market is described as moving closer to EU practice, but wider Western Balkan market coupling remains unfinished.
15-minute day-ahead trading from September 2025
The transition described includes a change in trading granularity inside the EU electricity-market framework. From 30 September 2025, day-ahead trading moves to 15-minute products instead of hourly scheduling. The European Commission says shifting from hourly to 15-minute pricing helps markets reflect expected generation and demand more accurately.
The change is presented as relevant for systems with high wind and solar shares because imbalances can appear within shorter time intervals than traditional hourly markets captured. For South East Europe’s operating conditions, this implies a different hierarchy of value across technologies and services. Pure generation remains important, but flexible generation becomes more valuable under tighter hour-by-hour balancing needs.
Technology value shifts toward controllable capacity
The value hierarchy described places solar with storage or flexible offtake above standalone solar output. Hydro remains strategic but its availability depends on weather conditions. Coal continues to be relevant for security of supply while its economics are weakening under carbon and pollution pressure.
Grid capacity is also described as changing role in price formation compared with earlier treatment as background infrastructure. In parallel with these shifts, investment priorities mentioned include batteries, pumped hydro, grid upgrades, balancing-market participation and demand response. Other items listed are shaped PPAs and smarter trading capabilities aimed at managing short-interval needs.
The investment implication stated is that South East Europe does not only need more megawatts but more controllable megawatts for balancing purposes . This framing connects back to a central thesis for electricity markets in 2026–2028: the crisis has changed shape from shortage concerns toward flexibility scarcity .
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