Developers and grid planners across Southeast Europe are being forced to treat carbon exposure as a routing constraint, not just a market signal. In the first quarter of 2026, the Carbon Border Adjustment Mechanism began to influence not only contract economics but also the physical and commercial patterns that transmission system operators must accommodate. The result is a fast-evolving corridor map with direct implications for interconnector value, cross-border scheduling discipline, and the readiness of infrastructure pipelines.
While wind and solar expansion continues to drive long-term generation diversification in the region, near-term dispatch and trading behaviour are increasingly shaped by regulatory risk around transit. That shift is changing how developers model revenue stacks for transmission assets and how EPC teams prepare studies for grid reinforcement under more complex flow patterns. For investors, it raises questions about whether congestion-based assumptions remain bankable when carbon-related costs alter trade incentives.
CBAM-linked corridor fragmentation in Q1 2026
For years, the Western Balkans operated as a transit bridge that linked EU systems through multi-leg arbitrage. Routes built around price differentials—such as Hungary–Serbia–Bulgaria and Croatia–Serbia–Romania—were not incidental; they supported trading strategies spanning several markets. That operating logic has started to fragment as CBAM introduces uncertainty over how electricity passing through non-EU countries should be treated.
In Q1 2026, commercially scheduled cross-border exchanges between the Western Balkans and the EU fell by approximately 25% versus the same period in 2025. The decline was asymmetric: EU-to-Western Balkans flows dropped by 40.7%, while flows in the opposite direction declined more modestly. The net effect moved the Western Balkans from a net importer to a net exporter of electricity by about 1.35 TWh, driven primarily by collapsed imports rather than a surge in exports.
From an operational planning perspective, this matters because traders adjust schedules to manage CBAM exposure while electricity still moves according to grid physics. That divergence increases the likelihood of congestion management challenges, loop flows, and operational instability for system operators coordinating cross-border transactions. It also complicates how market participants forecast deliverability when contracts and physical trajectories no longer align.
Transit risk pushes flows toward “CBAM-efficient” pathways
The reduction in EU-to-Western Balkans exchanges is tied to disruption of transit-based trading strategies. Under CBAM, traders face risk that electricity transiting through non-EU territories could attract carbon costs even if it originates and is consumed within the EU. This regulatory ambiguity has discouraged use of Western Balkans corridors for intra-EU trade, encouraging reconfiguration toward routes that remain within EU jurisdiction or rely on low-carbon systems.
The emerging alternative geography includes direct EU-to-EU interconnections and pathways incorporating low-emission generation capable of avoiding CBAM-related costs. For grid modernization teams, this shift changes where reinforcement may be needed most urgently: not only where demand grows from renewables integration, but where rerouted flows concentrate under carbon-driven trading behaviour. It also affects how technical studies translate market assumptions into power-flow cases for planning horizons.
Albania’s hydro advantage redirects supply chains
Albania has become a notable beneficiary of the corridor reconfiguration due to its hydro-dominated generation mix and an effective default emission factor effectively equal to zero under CBAM conditions. In Q1 2026, Albania increased scheduled exports across all borders, including flows to Greece, Kosovo, and Montenegro. The net effect was a redistribution of approximately 1.2 TWh compared with the same period in 2025.
Importantly for infrastructure planning, this surplus did not remain local. It moved through Greece into EU markets including Bulgaria and Italy, with Greece acting as an intermediary supported by a substantial increase in hydro generation. The resulting south-to-north corridor—anchored by low-carbon supply—has gained prominence as an alternative to traditional transit routes through coal-heavy systems.
This pattern highlights how route optimisation is shifting from purely economic or physical criteria toward carbon exposure minimisation. For wind and solar project developers that rely on predictable balancing and curtailment economics, such changes can influence regional price formation dynamics even when their assets are not directly connected to the most affected interconnectors.
Intra-Western Balkans trading strengthens liquidity but reduces EU linkage
As cross-border exchanges with the EU become more constrained, intra-regional trading within the Western Balkans intensifies. Markets within the region are turning inward, supported by surplus generation—particularly hydro—and reduced attractiveness of exporting to the EU under CBAM conditions. The outcome is a more interconnected intra-WB6 market that remains less integrated with EU pricing signals.
For market design stakeholders and operators monitoring liquidity, this inward shift supports liquidity and price discovery within Western Balkans markets but does not fully compensate for reduced access to higher-priced EU venues. The net effect is redistribution of trading activity rather than expansion, which can influence revenue depth for utilities and alter hedging strategies used by industrial off-takers.
Interconnector performance shows CBAM’s impact on utilisation
The Montenegro–Italy submarine cable illustrates how regulatory exposure can override traditional congestion economics. Despite offering a direct link between a lower-priced Western Balkans market and a higher-priced EU market, utilisation declined in Q1 2026. Scheduled flows from Montenegro to Italy fell by over 2,100 MWh per day, while physical flows decreased by approximately 1,400 MWh per day even as the price spread widened significantly.
This suggests interconnector value is increasingly influenced by the regulatory environment—specifically carbon costs associated with cross-border trade—rather than price differentials and capacity constraints alone. Assets linking low-carbon systems to the EU retain or can increase their relevance, while links tied to high-emission corridors face declining utilisation and reduced economic justification.
Commercial schedules diverge from physical flows
A further complication for transmission planning is the mismatch between commercial intent and physical reality. Traders adjust schedules to minimise CBAM exposure, but electricity continues to flow according to grid characteristics. In one example of that divergence, increased commercial exports from Albania to Greece were not fully reflected in physical flows along that route because power continued moving through Montenegro and Bosnia and Herzegovina toward EU markets.
This scheduling-physics gap introduces inefficiencies that system operators must manage through congestion control measures and operational coordination across borders. For engineering study teams preparing load-flow scenarios for new interconnectors or grid reinforcements, it underscores why assumptions about “where power goes” must be tested against realistic network behaviour rather than contract-level routing logic alone.
Implications for EPC preparation, permitting assumptions, and CAPEX planning
The changing geography of trade forces reassessment of infrastructure development assumptions built around stable arbitrage flows. Interconnectors previously expected to generate strong congestion revenues may see reduced utilisation if carbon-driven routing continues to bypass certain corridors or if transit treatment remains uncertain under CBAM frameworks. At the same time, new opportunities may emerge where projects connect low-carbon supply sources or bypass high-emission regions.
For procurement frameworks and EPC preparation teams working on transmission infrastructure upgrades supporting renewables integration—including wind and solar—the key challenge is aligning technical studies with evolving commercial behaviour. That includes updating engineering cases used for design verification, revisiting operational readiness assumptions for congestion management systems, and ensuring permitting narratives reflect likely flow patterns rather than historical scheduling norms.
What could change next
Future trajectory depends on several factors affecting regulatory clarity and incentive alignment. Greater clarity on how transit flows are treated under CBAM could restore some attractiveness of Western Balkans corridors for intra-EU trade. Adjustments to emission factor methodologies could reduce disparities between systems and mitigate distortions observed in current routing behaviour.
In parallel, development of carbon pricing mechanisms within the Western Balkans could align incentives between EU-linked markets and non-EU jurisdictions, reducing asymmetry that currently drives corridor avoidance behaviour. Even so, carbon pricing appears set to remain central to electricity market design, meaning corridor reconfiguration seen in Q1 2026 is likely an early stage of longer-term transformation rather than a short-lived anomaly.
Broader industry takeaway: Southeast Europe’s grid planning now needs tighter integration between carbon-aware market modelling and power-system engineering studies—especially for transmission investments whose business cases depend on utilisation patterns shaped by regulation as much as by capacity constraints.