Electricity markets across Southeastern Europe opened the new trading week on 25 May 2026 with a strong upward correction. Demand recovered sharply after the weekend slowdown, while renewable generation weakened across several balancing zones. The return of evening scarcity pricing lifted most regional exchanges, with Serbia emerging as the highest-priced market in the wider SEE region.
Demand and generation mix shift after the weekend
Regional consumption increased by more than 2 GW day-on-day to approximately 25,836 MW. The generation mix deteriorated, particularly in hydro and wind output, tightening system balances. This also increased reliance on imports from Central Europe.
Hydropower production declined by around 636 MW to 5,982 MW. Wind generation fell by approximately 305 MW to 3,848 MW. Solar output softened by more than 220 MW, easing midday oversupply conditions that had recently driven negative pricing.
Day-ahead price rebound led by Serbia
Regional electricity prices rebounded sharply following the change in supply and demand conditions. Serbia’s SEEPEX recorded the highest day-ahead base price in the region at 108.60 EUR/MWh, rising by more than 32 EUR/MWh day-on-day. Slovenia followed at 103.38 EUR/MWh.
Croatia reached 99.59 EUR/MWh, Romania posted 93.92 EUR/MWh, and Hungary’s HUPX settled at 91.39 EUR/MWh. Greece remained structurally lower at 73.44 EUR/MWh, supported by stronger solar penetration and softer balancing pressure in the southern zone.
Northern premiums and wider price fragmentation
The spread structure pointed to growing fragmentation across the SEE electricity market. Serbia traded more than 17 EUR/MWh above Hungary, while Slovenia maintained a premium of nearly 12 EUR/MWh over HUPX. Greece, Montenegro and North Macedonia continued trading at significant discounts versus northern SEE markets.
The discounts were linked to divergent renewable profiles and persistent cross-border transmission bottlenecks. Hourly pricing patterns also showed continued separation between midday renewable conditions and later scarcity periods once solar output collapsed.
Negative midday pricing and evening scarcity hours
Negative prices appeared across interconnected markets despite a higher daily average level. Hungary recorded lows of -10.5 EUR/MWh, while Slovenia dropped to -29.3 EUR/MWh. Austria briefly plunged to -50.4 EUR/MWh during the solar peak.
Evening ramp-up pricing returned strongly across the region, with most exchanges recording daily highs during hour 21 or 22. Hungary peaked near 178 EUR/MWh, Romania at 178.2 EUR/MWh, and Croatia at 179.5 EUR/MWh. Slovenia briefly reached 180 EUR/MWh, indicating extreme intraday volatility.
Borders flows tighten balances as imports rise
This pattern of negative midday pricing alongside high evening spreads was reflected in cross-border flow dynamics as regional balances tightened. Greece imported roughly 1,098 MW, while Serbia remained one of the region’s largest importing nodes with approximately 1,365 MW net imports. Romania exported around 826 MW.
The export position for Romania was associated with stronger domestic generation availability and favorable interconnection positioning. The same volatility profile had been highlighted in earlier ACER analysis focused on periods of renewable intermittency and peak evening demand.
ACER flags transmission limits and flexibility gaps
The ACER assessment identified Southeastern Europe as one of the most vulnerable regions during renewable intermittency combined with peak evening demand. It cited insufficient transmission capacity, limited system flexibility, and constrained cross-border integration as drivers of persistent volatility.
ACER also emphasized accelerated grid modernization, including dynamic line rating systems, network-enhancing technologies, and expanded storage deployment. These recommendations align with ongoing investments across Romania, Bulgaria and Slovenia involving battery projects and digital grid upgrades alongside renewable capacity growth.
Gas forwards, carbon allowances and coal prices steady
Fuel and carbon markets remained relatively stable despite sharp electricity price movements in the region. Austrian CEGH gas forwards traded near 49.51 EUR/MWh, while EU carbon allowances were elevated at approximately 76.92 EUR/t. API2 coal contracts held around 126 USD/t for June delivery.
The persistence of high carbon prices continues shaping generation economics across the Balkans. Coal represented around 14% of regional generation, with elevated EUA costs increasingly pressuring lignite-heavy systems as renewable penetration expands and carbon exposure intensifies.
Temperatures forecast to lift cooling demand into midweek
Weather forecasts indicate rising temperatures across SEE markets in the coming days, particularly in Serbia, Romania and Montenegro. Levels could approach 24–26°C by midweek. Higher cooling demand combined with stronger solar output may intensify midday price collapses followed by evening scarcity spikes.
The current market structure was described as resembling mature Western European renewable patterns but without comparable flexibility infrastructure or storage penetration. Volatility is expected to remain elevated through the summer period, especially across Serbia and neighboring SEE markets where transmission constraints, thermal dependence and renewable intermittency continue interacting within a stressed regional balancing system.