The electricity markets in South-Eastern Europe (SEE) are undergoing significant transformations, revealing a complex interplay of regional corridors that shape pricing and risk management. National energy systems, while still maintaining control over generation assets and regulatory frameworks, find themselves increasingly influenced by external factors. The interdependence among nations has evolved, making the region’s electricity landscape behave more like a unified but imperfectly integrated market.
This analysis highlights four critical dimensions of the current electricity dynamics: the geography of interdependence, the operational mechanics that dictate market stability, the types of entities influencing price outcomes, and a framework to quantify how minor capacity constraints can lead to substantial price fluctuations. These elements collectively illustrate why electricity prices in SEE have become more volatile despite ongoing market reforms and why traditional policy responses often fail to address underlying issues.
Historically, electricity risk was primarily domestic; however, recent developments have shifted this paradigm. Factors such as hydrological variability, intermittent renewable energy sources, aging thermal power plants, and limited market coupling have redirected marginal pricing from national supply chains to cross-border interfaces. Consequently, corridors—transmission pathways—have emerged as pivotal assets that determine whether scarcity is shared or isolated within markets.
Three key corridors now dominate the economic landscape of SEE electricity: the Hungary–Serbia corridor serves as a critical link between Central European liquidity and the Western Balkans; the Bulgaria–Romania corridor acts as a structural backbone for stress propagation across the region; and the Italy-SEE link has transitioned into a vital arbitrage channel for energy flows between Adriatic and Balkan systems. These corridors not only impact their immediate countries but also influence broader regional outcomes.
In periods of tight supply when domestic resources are stretched thin, prices are predominantly influenced by import availability rather than physical capacity alone. The timing and access to these imports become crucial in determining price levels during peak demand hours. When corridors remain open, they help alleviate scarcity; conversely, when constrained, they can lead to significant local price spikes.
The Hungary–Serbia interface exemplifies this phenomenon. Hungary’s integration into the EU’s coupled market provides it with robust liquidity and balancing capabilities. In contrast, Serbia faces challenges related to renewable variability and declining coal flexibility. This corridor primarily functions not as a conduit for average energy flows but as an insurance mechanism during critical stress periods. For Serbia, timely access to Hungarian energy can stabilize prices; for Hungary, it offers an avenue to manage surplus or mitigate stress depending on prevailing conditions.
Empirical data shows that during stressed conditions—accounting for less than 5% of total hours—minor adjustments in capacity at this interface can yield substantial reductions in prices across the Serbian market zone. An increase of just 100 MW can decrease prices by €10–18/MWh during these hours, translating into significant savings across the system.
The Bulgaria–Romania corridor functions as another essential component in maintaining regional price alignment. Romania contributes with its substantial renewable capacity while Bulgaria offers legacy baseload generation and extensive interconnection capabilities. This corridor facilitates both surplus transfers from Romania to Bulgaria and stress flow from Central Europe towards Greece and the Balkans. When operational constraints arise in this corridor, it leads to fragmented pricing across downstream markets—a situation that exacerbates volatility and creates wider spreads between neighboring markets.
Italy plays a crucial role within this interconnected framework through its demand dynamics influenced by gas-priced generation. The interconnections with Montenegro and other Adriatic regions allow Italian price movements to significantly affect surrounding markets. Rising prices in Italy can attract exports from Balkan systems while falling prices provide an outlet for surplus renewable energy from SEE countries.
In terms of pricing power within this complex landscape, traditional narratives about dominant generators do not capture the full picture. Transmission system operators (TSOs) emerge as key influencers due to their decisions regarding capacity availability and outage scheduling which can dramatically affect downstream prices during stressed conditions. Additionally, border-access arbitrage traders capitalize on timing discrepancies at constrained interfaces while balancing-market optimizers set effective security prices using fast-response assets like hydro or batteries.
Despite the evident value of these corridors in stabilizing markets, several structural challenges hinder their effectiveness. Fragmented flexibility across SEE systems limits rapid response capabilities during stress events; conservative capacity allocation practices convert potential regional cooperation into localized price shocks; shallow intraday liquidity exacerbates volatility during adjustment periods; misaligned remuneration structures fail to incentivize investment in essential assets needed for reducing overall market volatility.
The economics surrounding additional capacity highlight a non-linear relationship between available resources and market impact. For instance, releasing just 100 MW during periods of high demand can significantly enhance system-wide value compared to larger capacities available at less critical times. This underscores the importance of treating corridors as strategic infrastructure rather than merely conduits for energy flow.
Ultimately, achieving stability within South-Eastern Europe’s electricity transition requires managing inherent volatility rather than eliminating it altogether. By prioritizing corridor accessibility during peak demand hours and enhancing intraday market mechanisms aligned with system value creation, stakeholders can better navigate this intricate web of interdependencies while fostering a more resilient regional electricity market.
