During the second quarter of 2026, the gap between commercial electricity schedules and physical power flows widened across the Western Balkan transmission network, increasing operational complexity for transmission system operators (TSOs). The divergence was visible at multiple border points, with different patterns emerging on specific interconnectors.
BiH–Croatia border: exports down in schedules, up in physical flows
The Bosnia and Herzegovina–Croatia border showed the largest contrast between nominated and actual power movements. Scheduled exports from Bosnia and Herzegovina to Croatia decreased by around 43% year on year to approximately 282 GWh. In the same direction, physical flows rose by roughly 270%, with more than 800 GWh crossing the border.
As a result, physical electricity moved at almost three times the volume indicated by commercial schedules. The discrepancy had already appeared in the first quarter but became more pronounced during Q2. This shift increased the difference between expected network loading and observed loading conditions.
Albania–Greece border: schedules stable while physical flows fall
At the Albania–Greece border, the direction of change differed from BiH–Croatia. Scheduled Albanian exports remained close to their usual level, increasing by around 3%. Physical flows fell approximately 63% in the same period.
Electricity commercially scheduled towards Greece appeared instead to move northwards through Montenegro and Bosnia and Herzegovina. This indicated that nominated transactions did not align with the path taken by physical power across the interconnected grid.
South-to-north route strengthens in broader physical-flow data
Broader physical-flow figures pointed to a strengthening south-to-north route across the region. Physical flows from Greece to North Macedonia increased by more than 200%, while North Macedonia-to-Serbia flows rose by a similar magnitude. Physical flows from Montenegro to Bosnia and Herzegovina also increased by more than 200%.
The interconnected network therefore carried electricity towards Croatia and other EU borders regardless of where commercial transactions had been nominated. This pattern linked multiple corridors through observed physical movements rather than scheduled directions alone.
Implications for grid security analysis and remedial actions
For TSOs, commercial schedules are a key input into grid-security analysis. They support estimates of expected network loading, help determine available margins, and enable preparation of remedial actions. When physical electricity follows a different path from the commercially nominated transaction, TSOs must keep larger safety margins.
In such cases, TSOs intervene more frequently using redispatch, countertrading and other corrective measures. These interventions add system costs that can be reflected in network tariffs, congestion-management costs, and lower transmission capacity available to market participants.
Role of CBAM-linked routing changes and regional coordination needs
The mismatch can also affect how congestion revenues align with underlying physical congestion. Income can accrue at one border even when congestion occurs elsewhere in the network. CBAM may contribute indirectly by changing commercial routes used for scheduling decisions.
Traders respond to national default emission factors, cross-border price spreads and eligibility requirements, while physical electricity continues to follow the laws of the interconnected grid. Greater divergence between commercial incentives and physical power flows increases operational pressure on grid operators.
The issue requires coordination beyond individual TSOs. Coordinated capacity calculation, common network modelling and regional congestion management are expected to become increasingly important across the Western Balkans and neighbouring EU markets. Greater transparency around loop flows is also needed alongside harmonised approaches to sharing costs for remedial actions.
Commercial reconfiguration outpaces physical grid adaptation
The regional electricity market is being commercially reconfigured faster than the physical grid can adapt. This growing gap creates infrastructure and regulatory costs that are expected to feed into network tariffs, grid investment requirements, and the amount of cross-border transmission capacity that can safely be made available to traders.
