Southeast Europe’s electricity exchanges showed striking physical integration during parts of August, with several national markets clearing within a few euros of one another.
At the same time, CBAM is creating a new economic boundary between EU and non-EU electricity.
On Aug. 19, day-ahead prices in Hungary, Romania, Bulgaria, Slovenia and Croatia converged around €168/MWh, with only about €0.30/MWh separating the group.
On Aug. 25, Hungary, Romania, Bulgaria, Greece, Croatia and Slovenia traded within roughly €173.7-€175.7/MWh.
That degree of convergence demonstrates the effect of interconnected markets and regional trading.
But it remains incomplete.
Serbia traded around €157.95/MWh on Aug. 25.
On Aug. 31, Hungary stood near €173.41/MWh, Romania €174.90/MWh, Slovenia €173.61/MWh, Croatia €172.28/MWh and Bulgaria and Greece €171.24/MWh, while Serbia cleared at only €132.21/MWh.
That represented a discount of more than €40/MWh to Romania.
Transmission availability, local generation and national market structures account for part of the difference.
CBAM introduces another variable.
During the first quarter of definitive CBAM implementation, commercial electricity exchanges between Energy Community markets and neighbouring EU systems fell by around 25%, while Energy Community prices averaged roughly €30/MWh below adjacent EU markets.
Trade recovered partly during the second quarter, but the mechanism continues to alter the economics of exports from carbon-intensive non-EU systems.
Renewable generators face a different problem.
Their electricity may have very low actual emissions, but monetising that advantage requires a defensible chain linking production, scheduling, contractual allocation and the EU importer.
That gives low-carbon traceability a direct commercial role.
For Serbia, Montenegro, Bosnia and Herzegovina and North Macedonia, market integration is therefore becoming a two-part process.
Physical interconnection can narrow wholesale-price differences.
Carbon treatment can create a new distinction based on the origin and verifiability of the electricity itself.
The result is likely to be a regional market increasingly segmented not only by borders and transmission constraints, but by the carbon credentials of each traded MWh.
