Week 25 showed widening electricity price differentials across Southeast Europe, reflecting the role of physical power flows. Market prices ranged from €16.66/MWh in Türkiye to €127.69/MWh in Italy. Greece was at €85.50/MWh, Serbia at €85.73/MWh, Bulgaria at €87.58/MWh, Croatia at €102.36/MWh, Romania at €104.84/MWh, and Hungary at €109.16/MWh. These gaps indicate potential value only when sufficient interconnector capacity is available for cross-border transfer.
In that context, the value of transmission capacity is increasing across the region as spreads widen between markets. A recurring metric based on cross-border congestion premium has been proposed to reflect the economic value of interconnector access between lower- and higher-priced zones. Such an indicator would incorporate more than the price spread alone. It would also account for available transmission capacity, congestion constraints, losses, nomination requirements and balancing risk.
Interconnector corridors highlighted by Week 25 spreads
Serbia–Hungary is identified as one of the most important corridors for cross-border flows. A Week 25 spread of €23.43/MWh was cited as creating incentives for transfers between the two markets. The Bulgaria–Romania corridor is also described as highly relevant due to Bulgaria’s relatively cheaper export position and Romania’s increasing price volatility.
Southbound links are described as playing specific roles in regional balancing conditions. The Greece–Bulgaria connection is referenced as a key balancing link in the south of the region. The Croatia–Slovenia–Italy axis is noted as particularly significant because Italy is described as the region’s main high-price demand sink.
Seasonal outlook for congestion value
Congestion value is expected to increase during the summer period, according to the outlook provided. Strong solar generation during midday hours can create localized surpluses in parts of the system. At the same time, evening demand peaks are described as continuing to generate scarcity conditions elsewhere.
This divergence is linked to the importance of flexible transmission access and operational execution across borders. Precise scheduling and effective nomination strategies are highlighted as factors that influence whether cross-border value can be captured under changing conditions. The same setup affects how physical transfers align with price differentials during different times of day.
Implications for market participants and revenue capture
For renewable developers, rising congestion risk can reduce capture prices in areas behind constrained network nodes. This can lower realized revenue even during high-output periods. For traders, congestion adds layers of optionality alongside potential arbitrage opportunities.
Industrial consumers are also described as being affected through procurement costs when transmission constraints pass through higher regional price levels domestically. Although Southeast Europe continues moving toward deeper market integration, progress is characterized as uneven across the region. That uneven integration is described as contributing to persistent congestion premiums that shape trading opportunities and structural price formation.
