Wholesale power prices increased across most of Southeast Europe during Aug. 17-23 even as aggregate electricity demand weakened. The pattern points to generation timing and availability playing a larger role in price formation than total consumption alone. Greece recorded the largest weekly rise, with its day-ahead average climbing 41.2% to €144.41/MWh.
Bulgaria’s day-ahead average increased 16.9%, while Hungary rose 7.2%, Romania gained 6.6%, Croatia added 6.5% and Serbia climbed 5.8%. Italy remained the most expensive major market at €168.31/MWh. Weekly baseload comparisons, however, do not capture the full change in how prices behave within the day.
Evening price spikes versus solar-rich midday declines
Hourly prices across several markets approached or exceeded €200/MWh during evening hours while falling materially during solar-rich midday periods. This intraday shape is increasingly visible across Hungary, Romania, Bulgaria, Greece, Serbia, Croatia and Italy. The shift indicates that scarcity is becoming more time-specific rather than only linked to daily totals.
Serbia illustrates the change most clearly through SEEPEX pricing behavior. During August, SEEPEX prices exceeded €400/MWh during some evening peaks and occasionally approached €500/MWh, despite much cheaper periods earlier in the day driven by strong solar output. SEEPEX Chief Executive Miloš Mladenović said the widening swings are one of the defining features of the summer market.
Transmission load patterns reflect rooftop solar effects in Croatia
Croatia’s intraday dynamics also show a shift tied to demand measurement and solar output timing. Its transmission system reached a record summer load of about 3.4 GW around 20:00-21:00 on Aug. 11 after most solar generation had disappeared. Around 600 MW of rooftop solar increasingly suppresses measured grid demand during daylight hours before consumption returns to the transmission system in the evening.
This combination of higher evening prices and solar-influenced daytime conditions changes how market tightness is identified. A system can show sufficient electricity at 13:00 while experiencing shortage several hours later without any significant change in total daily consumption when solar penetration expands.
Implications for scarcity and flexible capacity economics
For much of the previous decade, regional electricity risk was discussed mainly around whether countries had enough annual or baseload generation capacity. With more solar capacity, the same daily energy balance can coexist with different hour-by-hour adequacy outcomes. That alters the relative value of technologies that can respond to changing price timing.
Hydropower that can conserve water for high-price hours becomes more valuable than inflexible generation producing the same megawatt-hours evenly across the day. Battery storage can buy electricity when solar output suppresses prices and sell during the evening ramp. Flexible industrial consumers can treat load reduction as an electricity-market asset.
Market rules and revenue protection for flexibility
Romania has already moved toward this approach by approving a framework under which eligible consumers can be paid to voluntarily reduce consumption during selected periods. The pattern also affects renewable project economics, particularly for merchant solar output facing lower capture prices precisely when production is highest. Co-located storage or contracts reflecting hourly market value can protect revenues.
For trading activity, the key spread is increasingly not limited to comparisons such as Serbia versus Hungary or Bulgaria versus Greece. Instead, it centers on the spread between midday energy and evening flexibility within each market, reflecting how intraday price separation develops under expanding solar generation.
The divergence between midday and evening pricing is expected to become more pronounced as Southeast Europe adds solar faster than it adds storage, dispatchable generation and transmission reinforcement. Even with higher installed generation overall, the highest-priced commodity increasingly becomes electricity available at the right hour rather than baseload availability alone.
