Several Southeast European electricity markets showed a high degree of physical integration during parts of August, with multiple national power exchanges clearing at similar levels. At the same time, the EU’s Carbon Border Adjustment Mechanism is creating a new economic dividing line between EU and non-EU electricity markets. The interaction between cross-border trading and CBAM effects is reflected in day-ahead price movements across the region.
August day-ahead price alignment across EU-adjacent markets
On August 19, day-ahead prices in Hungary, Romania, Bulgaria, Slovenia and Croatia converged at around €168/MWh. The spread between the markets narrowed to approximately €0.30/MWh. A similar pattern appeared on August 25, when Hungary, Romania, Bulgaria, Greece, Croatia and Slovenia traded within a relatively narrow band of approximately €173.7–€175.7/MWh.
This convergence points to the role of cross-border interconnection and regional electricity trading in aligning market outcomes to shared supply and demand conditions. However, the alignment did not extend uniformly across the region. Serbia’s pricing level on August 25 was already below the closely aligned EU-adjacent markets.
Incomplete integration as Serbia diverges from regional levels
Serbia traded at approximately €157.95/MWh on August 25, sitting below the cluster of EU-adjacent prices. By August 31, divergence widened further across several markets. Hungary cleared near €173.41/MWh, Romania at €174.90/MWh, Slovenia at €173.61/MWh, Croatia at €172.28/MWh, while Bulgaria and Greece were around €171.24/MWh.
On that same date, Serbia cleared at only €132.21/MWh, leaving a gap of more than €40/MWh compared with Romania. Transmission availability, domestic generation patterns and differences in national market structures are cited as factors behind part of this divergence.
CBAM impact on Energy Community exchanges and carbon-linked value
The CBAM framework is described as introducing additional economic differentiation between EU and non-EU electricity markets. During the first quarter of definitive CBAM implementation, commercial electricity exchanges between Energy Community markets and neighbouring EU systems declined by around 25%. Electricity prices in Energy Community markets averaged approximately €30/MWh below adjacent EU markets.
Cross-border trade recovered partially during the second quarter, but the mechanism continues to affect the economics of electricity exports from carbon-intensive non-EU power systems. For renewable generators, the challenge is different because their electricity may have very low direct emissions while value capture depends on linking generation data to market processes and documentation requirements at the EU border.
Traceability requirements for renewables trading across borders
The ability to capture economic value requires a credible chain connecting generation, scheduling, contractual allocation and verification at the EU border for low-carbon attributes. As a result, low-carbon traceability is described as becoming more than a regulatory requirement and increasingly a commercial asset for cross-border transactions.
For Serbia, Montenegro, Bosnia and Herzegovina and North Macedonia, regional electricity-market integration is developing along two parallel tracks: physical interconnection and market coupling on one side, and carbon regulation on the other. Physical integration can reduce wholesale price differences and increase trading efficiency, while carbon regulation can create a distinction based on where electricity originates and whether its carbon credentials can be demonstrated.
The segmentation described for Southeast Europe therefore extends beyond national borders, transmission constraints and local generation to include carbon characteristics and verifiability for every traded MWh.
