Electricity markets across Southeastern Europe opened the new trading week on 25 May 2026 with a strong upward correction. Regional demand recovered after the weekend while renewable generation weakened across several balancing zones. The return of evening scarcity pricing pushed most exchanges higher, with Serbia posting the highest price in the wider SEE region.
Regional consumption rose by more than 2 GW day-on-day to around 25,836 MW. At the same time, the generation mix tightened, particularly as hydro and wind output declined. This shift increased reliance on imports from Central Europe.
Hydropower production fell by about 636 MW to 5,982 MW, while wind generation dropped approximately 305 MW to 3,848 MW. Solar output also softened by more than 220 MW, reducing midday oversupply conditions that had recently contributed to widespread negative pricing events.
Prices rebounded sharply across the region. Serbia’s SEEPEX recorded the highest day-ahead base price at 108.60 EUR/MWh, up by more than 32 EUR/MWh day-on-day. Slovenia followed at 103.38 EUR/MWh, Croatia at 99.59 EUR/MWh, Romania at 93.92 EUR/MWh, and Hungary’s HUPX settled at 91.39 EUR/MWh.
Greece remained lower at 73.44 EUR/MWh. The southern zone saw support from stronger solar penetration and softer balancing pressure compared with northern markets.
The spread structure pointed to growing fragmentation of the SEE electricity market. Serbia traded more than 17 EUR/MWh above Hungary, while Slovenia held a premium of nearly 12 EUR/MWh over HUPX. Greece, Montenegro and North Macedonia continued at significant discounts versus northern SEE markets, linked to divergent renewable profiles and persistent cross-border transmission bottlenecks.
Hourly curves showed the region moving between midday renewable oversupply and evening scarcity conditions. Negative prices appeared across interconnected markets despite higher overall daily averages. Hungary recorded lows of -10.5 EUR/MWh, Slovenia fell to -29.3 EUR/MWh, and Austria briefly reached -50.4 EUR/MWh during the solar peak.
Evening ramp-up pricing returned across most exchanges. Daily highs were set during hour 21 or 22 as thermal generation regained marginality after sunset. Hungary peaked near 178 EUR/MWh, Romania at 178.2 EUR/MWh, Croatia at 179.5 EUR/MWh, and Slovenia briefly reached 180 EUR/MWh, reflecting extreme intraday volatility.
The pattern supported expectations for increased deployment of battery energy storage systems (BESS). Negative midday pricing combined with wide evening spreads creates expanding merchant arbitrage opportunities, particularly in Serbia, Romania, Bulgaria and Hungary where balancing markets are described as underdeveloped.
Cross-border flow data indicated tighter regional balances. Greece imported about 1,098 MW, while Serbia remained a major importing node with roughly 1,365 MW net imports. Romania exported around 826 MW, supported by stronger domestic availability and favorable interconnection positioning.
Strong earlier ACER analysis Strong highlighted Southeastern Europe as one of the most vulnerable regions during periods of renewable intermittency and peak evening demand. It cited insufficient transmission capacity, limited system flexibility and constrained cross-border integration as drivers of persistent volatility.
Strong grid modernization Strong was emphasized through measures including dynamic line rating systems, network-enhancing technologies and expanded storage deployment. The recommendations align with ongoing investments in Romania, Bulgaria and Slovenia, where battery projects and digital grid upgrades are expanding alongside renewable capacity growth.
Fuel and carbon markets were reported as relatively stable despite large electricity price moves. Austrian CEGH gas forwards traded near 49.51 EUR/MWh, EU carbon allowances were around 76.92 EUR/t, and API2 coal contracts were about 126 USD/t for June delivery.
The elevated carbon price level continues to affect generation economics across the Balkans. Coal accounted for around 14% of regional generation, while higher EUA costs increasingly pressure lignite-heavy systems as renewable penetration rises and carbon exposure intensifies.
Strong Weather forecasts Strong indicated rising temperatures across SEE markets over the coming days, especially in Serbia, Romania and Montenegro, with values approaching Strong 24–26°C Strong by midweek. Higher cooling demand together with stronger solar output may further intensify midday price drops 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 summer, particularly across Serbia and neighboring SEE markets where transmission constraints, thermal dependence and renewable intermittency interact within a stressed regional balancing system.
