Electricity trading in Southeast Europe moved higher in June 2026 as late-month heat increased cooling demand and reduced system flexibility. Comparing 16–30 June with 1–15 June, electricity prices rose across most regional markets. Hungary’s HUPX climbed to €149.01/MWh, up €48.7/MWh, while Romania’s OPCOM reached €146.80/MWh, up €47.6/MWh. Croatia and Slovenia followed at €136.67/MWh and €134.33/MWh, respectively.
Serbia’s SEEPEX increased to €114.87/MWh, and Montenegro’s BELEN averaged €108.63/MWh. Bulgaria and Greece recorded more moderate gains, ending the period at €99.72/MWh and €95.72/MWh. The price outcomes left Hungary with the region’s highest price premium.
Demand and temperatures tighten supply conditions
The main driver was higher electricity demand linked to rising temperatures. Average consumption across the HU+SEE region increased from 28,054 MW in the first half of June to 31,414 MW during the second half, a rise of 3,360 MW. Average temperatures across HU+SEE excluding Greece climbed from 20.3°C to 25.5°C, while Greece warmed from 24.1°C to 26.7°C.
As temperatures increased, the market shifted from a renewable-friendly shoulder season into an early-summer period with tighter supply conditions. By the end of June, the region moved from occasional export surpluses into significant import dependency. HU+SEE averaged -466 MW in net exports during the second half and fell to -2,682 MW on 30 June.
Generation increases across most technologies
Power generation expanded across nearly all technologies during the month-end period but did not fully offset demand growth. Gas-fired generation rose by 1,177 MW to 4,757 MW, while coal output increased by 476 MW to 5,014 MW. Nuclear generation climbed by 922 MW to 4,901 MW.
Wind and solar production increased by 841 MW and 894 MW respectively during the same period. Hydropower was the only major source to decline slightly, falling by 130 MW to 6,098 MW. Despite these changes, the regional generation mix remained heavily weighted toward renewables: solar at 23%, hydro at 20%, coal at 17%, gas at 16%, nuclear at 16%, and wind at 8%.
Pricing increasingly reflected flexible capacity availability during evening hours rather than average renewable output levels. Strong solar production pushed midday electricity prices close to zero or into negative territory in several markets. Evening price spikes became more pronounced as the month progressed.
Evening scarcity drives hourly price extremes
Regional price volatility was linked to dispatchability and flexibility requirements as solar output peaked during midday periods. Maximum hourly prices recorded during the reporting period included €923.1/MWh in Hungary, €954.6/MWh in Romania, €1,041.5/MWh in Slovenia, €946.6/MWh in Croatia, and €800/MWh in Serbia.
The pattern highlighted how storage capability, ramping capacity, interconnector availability and flexible generation affected market outcomes beyond total energy output alone.
Fuel costs fall while carbon prices rise
Lower fuel costs did not prevent electricity prices from rising across the region in late June. Average CEGH natural gas prices declined from €49.35/MWh to €43.06/MWh, while Greek gas prices fell from €46.14/MWh to €41.37/MWh.
At the same time, EU carbon allowance (EUA) prices increased from €77.85/t to €80.31/t. The second-half June price increase was therefore associated primarily with weather conditions, nuclear operating constraints, import dependence and evening residual-load scarcity rather than higher fuel costs.
Hungary faces nuclear cooling-water restrictions
Hungary became a key stress point within the regional market as demand reached new summer highs. Electricity demand reached a peak of 7,488 MW on 29 June. The Paks Nuclear Power Plant faced temporary operating restrictions after Danube cooling-water temperatures exceeded environmental thresholds.
Authorities granted a temporary exemption limiting the reduction in nuclear output to 40 MW, instead of a potential reduction of 640 MW. Combined heat conditions, high demand levels, nuclear cooling challenges and import requirements supported HUPX as the premium pricing benchmark across Southeast Europe.
Romania records dispatchable solar record but remains a net importer
Romania set a dispatchable solar generation record of 2,952 MW. The figure combined with approximately 1,930 MW of prosumer capacity pushed total midday solar output close to 5 GW. Despite this level of midday generation, Romania averaged -637 MW in net imports during the second half of June.
The results pointed to a gap between midday renewable availability and evening supply needs based on net import figures for that period.
Greece exports while maintaining lower average wholesale prices
Greece acted as a southern balancing hub during the observed period. Its average wholesale electricity price remained relatively low at €95.72/MWh. Greece averaged 1,385 MW of net exports during the same timeframe.
The generation mix comprised 36% gas, 33% solar, and 22% wind. Greece exported both surplus renewable energy and flexible gas-fired generation northward into Bulgaria, North Macedonia and Albania while maintaining system stability.
Serbia posts higher trading volumes amid import dependence
Serbia’s market showed mixed but strategically important indicators for June trading dynamics. SEEPEX averaged €114.87/MWh, while day-ahead market trading volume reached a record monthly level of 569,139 MWh. This represented a 12.6% year-on-year increase.
The country remained structurally import-dependent with an average net export position of -706 MW during the period reported for net flows. Generation was dominated by coal at 66% and hydropower at 32%.
The fundamentals continued to align with investment plans including Serbia’s planned 1 GW solar program, combined with at least 200 MW / 400 MWh of battery storage. Financing discussions continued for the Bistrica pumped-storage project alongside new wind developments including Alibunar.
Montenegro relies on imports while transmission upgrades progress
Montenegro’s BELEN averaged €108.63/MWh, while it remained a net electricity importer at -77 MW during the observed period. State utility EPCG spent approximately €142 million on electricity imports during 2025. The spending followed an outage at TPP Pljevlja along with weak hydrological conditions.
Around 780 GWh of imported electricity replaced lost thermal generation, while another 320 GWh compensated for lower hydropower production due to hydrology constraints.
CGES planned transmission upgrades at Perucica and Pljevlja that could enable approximately 550 MW of new renewable energy connections. Improvements along the Trebinje–Perucica–Podgorica–Vau i Dejes corridor could increase cross-border transfer capacity to around 600 MW.
Batteries and grid projects expand across Bulgaria, Hungary and Romania
Bulgaria expanded its storage portfolio with several new battery projects including Solarpro’s 602 MWh Burgas facility. Hungary commissioned new storage systems in Tiszaujvaros and Ajka during June’s broader investment activity described for the region.