Southeast Europe’s electricity market entered a new structural phase during CW21, with renewable volatility, negative-price risk, cross-border balancing pressures and transmission bottlenecks increasingly shaping regional power pricing. Market signals across Serbia, Romania, Hungary, Bulgaria, Croatia and Greece indicate the region is not operating as a conventional coal-and-hydro system. Instead, wind generation, solar output, interconnection availability and balancing flexibility are increasingly linked to how prices form.
The change in pricing conditions was visible through a sharp reversal between Week 19 and Week 21. During Week 19, regional prices moved above €100/MWh across nearly all major SEE markets as wind output weakened. Thermal dispatch increased and gas-linked marginal pricing re-emerged during that period. Italy reported average weekly baseload prices of €131.47/MWh, while Romania reached €123.34/MWh, Hungary €122.62/MWh, Croatia €117.37/MWh, Bulgaria €111.41/MWh, Serbia €111.36/MWh and Greece €106.30/MWh.
Serbia recorded one of the largest week-to-week changes, with average weekly prices rising by approximately 29.25%. Days later the market reversed again as conditions shifted across the region. By 20 May 2026, renewable generation recovered in much of Southeast Europe as temperatures increased, and regional spot prices fell substantially. The correction speed reflected how SEE electricity markets increasingly behave like short-cycle balancing systems rather than stable thermal-based pricing environments.
Wind-driven price moves and divergence between spot and forwards
Wind-generation volatility became a key factor in the latest price swings. On 18 May, regional power prices surged after wind output collapsed across parts of Central and Southeast Europe. Hungarian Week 21 baseload forwards traded near €118.5/MWh, while June 2026 contracts remained above €113/MWh despite short-term spot-market weakness.
Week 20 data also pointed to shifting supply conditions affecting pricing outcomes. Serbian electricity prices fell by approximately 12.5% week-on-week as renewable generation improved. Wind generation rose from previous lows while hydropower output collapsed by nearly 50%. Net imports increased by more than 251% week-on-week during the same period.
Negative-price logic also appeared within Southeast Europe during CW21. Negative prices and near-zero intraday pricing events are described as no longer limited to Western European markets. Instead, they are increasingly part of the Balkan market structure itself.
Carbon costs and gas-linked risk in coal-dependent systems
EU carbon pricing supported higher thermal generation costs across coal-dependent markets in the region during CW21. EU Allowance prices stabilized near €75.6/tCO₂. The same period included expectations that EU ETS pressure would intensify further during the second half of the decade.
The carbon-price linkage was highlighted for countries including Serbia, Bosnia and Herzegovina and North Macedonia, along with parts of Romania and Bulgaria still reliant on coal generation. Alongside carbon costs, European Commission analysis published during CW21 warned that post-Russian European gas markets are becoming more volatile due to LNG dependence and changing electricity-gas linkages. For Southeast Europe this meant gas price shocks could still rapidly reprice electricity markets when wind or hydro output is low.
This relationship was described as structural because Southeast Europe’s power markets remain connected to European gas pricing through marginal generation costs and balancing requirements.
Batteries expand for trading and balancing; transmission becomes a bottleneck
Battery storage investment accelerated during CW21 as volatility management needs increased. Storage projects across Southeast Europe were described as being developed not only for renewable integration but also as merchant trading and balancing assets able to arbitrage volatility, intraday spreads and negative pricing events. In Montenegro, Elektroprivreda Crne Gore advanced planning tied to approximately 500 MWh of battery-storage capacity.
Romania-based Nofar Energy accelerated plans for approximately 860 MWh of battery storage projects during the same period. These figures were presented as evidence that storage is becoming a standalone investment class across Southeast Europe.
CW21 also indicated that transmission infrastructure is emerging as a central constraint for the energy transition. Renewable project pipelines across Serbia, Romania, Bulgaria, Croatia and Montenegro were described as expanding faster than transmission-system modernization efforts. Grid congestion and curtailment risk were identified as among the most important bankability issues for new renewable projects.
The renewable pipeline included multiple project milestones reported during CW21. Chinese manufacturer SANY Renewable Energy confirmed plans to start construction of the Alibunar 1 and Alibunar 2 wind projects in Serbia by the end of June. Montenegro’s Elektroprivreda Crne Gore moved forward with trial operations at the 55 MW Gvozd wind farm expected to generate approximately 150 GWh annually.
Solar licensing, hydropower refurbishment and regional investment totals
Romania remained active on renewables investment during CW21 through both solar expansion and grid-balancing assets. DRI received a commercial operating licence for its 126 MW Văcărești solar park near Bucharest. Hydropower also featured in system flexibility developments through a refurbishment contract signed by Hidroelectrica.
Hidroelectrica signed a €188.5 million refurbishment contract for the Râul Mare Retezat hydropower plant during CW21. The contract was cited alongside other developments showing how flexible hydro generation can support renewable-heavy electricity systems.
The decade-ahead investment requirement was estimated at between €50 billion and €80 billion of cumulative energy-system investment for Southeast Europe this decade based on regional decarbonization and energy-transition estimates. The capital was described as concentrating in transmission infrastructure, battery storage, renewable generation, balancing capacity, interconnections, digital grid systems and flexible hydro modernization.
The broader implication attributed to CW21 was that Southeast Europe’s electricity market is moving into a structurally different trading regime rather than transitioning gradually toward renewables. Renewable intermittency, balancing flexibility, cross-border flows and storage economics were described as increasingly defining price formation, investment returns and long-term energy security within the region.
