What drives price divergence in Central and South-Eastern Europe? Evidence from flow-based market coupling

Electricity prices in Central and South-Eastern Europe exhibited extreme divergence during the summer of 2024, followed by a period in which price differentials remained persistently higher than in Western Europe. This paper investigates the extent to which flow-based market coupling (FBMC) contributed to these outcomes by constraining cross-zonal trade. Using publicly available data, we conduct a critical network element-level empirical analysis that decomposes hourly price differences into the contributions of individual network constraints. The results show that a small number of network elements account for the majority of observed price spreads between Central and South-Eastern Europe, even after controlling for demand conditions and generation fundamentals. Regression results confirm a strong and statistically significant relationship between the available transfer capacity for commercial flow on key critical network elements (RAM scarcity) and regional price divergence. The findings point to important scope for improving FBMC implementation and underline the importance of stricter enforcement of minimum cross-zonal capacity requirements, improved transparency of capacity calculation, and stronger investment incentives for internal grid reinforcements with cross-border welfare benefits.