SEE power prices jump as solar output slips and cross-border imports surge

South-East European electricity markets tightened on Friday, pushing day-ahead prices higher after weaker solar output, increased thermal dispatch and a surge in cross-border imports. The move matters for traders and utilities because it highlights how quickly the region’s pricing can swing when renewable generation drops and balancing resources are pulled in.

Day-ahead prices return above €120/MWh

Day-ahead prices rose across most regional exchanges following the deterioration in the supply balance. Hungary’s HUPX settled at €140.45/MWh, broadly flat versus the prior day but still among the highest-priced hubs in Central and Eastern Europe. Romania’s OPCOM climbed to €144.45/MWh, while Bulgaria’s IBEX rose to €131.75/MWh and Croatia’s CROPEX ended at €130.20/MWh.

Serbia’s SEEPEX increased to €122.42/MWh, while Greece’s HENEX remained structurally lower at €122.10/MWh even after recovering from earlier low-price sessions.

Solar drop drives reliance on imports and flexible generation

The price rebound followed a sharp fall in regional solar production across SEE plus Hungary, which dropped by roughly 1.5 GW day-on-day. Total photovoltaic output declined to around 4.5 GW from nearly 6 GW previously, leaving system operators and market participants more dependent on imports and flexible thermal generation.

Net regional imports rose to approximately 1,736 MW—up nearly 800 MW from the previous day—with imports into Hungary and SEE from the Central European CORE region exceeding 1.7 GW. At the same time, gas-fired generation increased by about 550 MW, while wind generation expanded by roughly 665 MW, partially offsetting the weaker solar conditions.

Market participants remained sensitive to renewable intermittency and evening ramping requirements, particularly because lower daytime solar coincided with stronger demand profiles later in the day.

Balancing pressure shifts the market back toward gas, imports and hydro

The region is increasingly reliant on flexible balancing resources during shoulder-season conditions. Once solar weakens further, the market is described as reverting quickly toward gas, imports and hydro balancing—an operational shift that tends to show up in both day-ahead levels and intraday price behavior.

Spreads widen; intraday volatility rises

The Hungary–Germany spread widened significantly to around €26.6/MWh from just above €4/MWh a day earlier. That change supported stronger commercial flows from Austria and Slovakia toward Hungary and the Balkans.

Romania stood out for intraday volatility: OPCOM evening hourly prices exceeded €300/MWh during late peak delivery periods, reflecting tighter balancing conditions and greater dependence on flexible dispatch capacity.

Renewables remain high despite the tightening

Even with higher day-ahead prices, renewable penetration across SEE stayed elevated. Hydro accounted for about 23% of the regional power mix, while solar and nuclear each contributed roughly 16%. Coal represented approximately 19% and gas around 14%.

Fuel and carbon markets provide a stable backdrop

Gas markets were described as relatively stable, with Austrian CEGH front-month contracts trading near €45.9/MWh. EU carbon allowances held close to €75/t, while coal forwards remained firm above $110/t—factors that continue to support thermal dispatch economics in coal-heavy Balkan systems.

Investment accelerates alongside rule changes for negative pricing

Bulgaria also commissioned two major flexibility-related projects this week: Rezolv Energy’s 225 MW St. George solar plant paired with a 90 MW / 240 MWh battery storage system; and Enery’s standalone 150 MW / 601.8 MWh battery installation near Nova Zagora, noted as among the largest operational storage facilities in Central and Eastern Europe.

The developments come as European market operators prepare for more volatile pricing tied to renewable oversupply and balancing stress. Under updated SDAC market rules, the harmonized minimum clearing price for European day-ahead markets will fall from -€500/MWh to -€600/MWh starting 28 May following repeated negative pricing events across multiple bidding zones during late April and early May.