South East Europe is not yet a single electricity market. Instead, it is better understood as two overlapping trading environments operating side by side.
The first is the EU-coupled market, which includes Hungary, Romania, Bulgaria, Greece, Croatia, and Slovenia. These countries are increasingly integrated into European day-ahead and intraday trading mechanisms. The second is the Western Balkan market, consisting of Serbia, Bosnia and Herzegovina, Montenegro, North Macedonia, Albania, and Kosovo. While these markets are moving toward integration, they still rely more heavily on explicit capacity allocation, national market rules, and developing exchange structures.
This distinction is important because market coupling fundamentally changes how cross-border value is captured and traded.
Within the EU framework, the Single Day-Ahead Coupling (SDAC) creates a pan-European cross-zonal day-ahead electricity market. Through a common algorithm, scarce cross-border transmission capacity is allocated while taking network constraints into account. In practice, market participants submit energy bids, and the algorithm automatically allocates available transmission capacity, creating a more efficient and integrated trading environment.
This differs significantly from an explicit-border model, where traders must separately acquire transmission capacity and nominate electricity flows. Explicit capacity trading can create opportunities, but it also introduces greater operational and financial risks. A trader may secure transmission rights only to discover that the expected price spread fails to emerge. In other cases, the spread may exist, but route limitations, nomination deadlines, or capacity-product restrictions can make the opportunity difficult to monetize.
Across South East Europe, both systems coexist.
On EU-coupled borders, traders increasingly compete through forecasting accuracy, bidding strategies, portfolio optimization, and imbalance management. On non-coupled Western Balkan borders, participants must also develop expertise in capacity auctions, route management, and robust operational risk controls.
The role of JAO and SEE CAO is therefore particularly important. JAO organizes cross-border transmission capacity auctions for European transmission system operators while providing clearing, settlement, contracting, reporting, and IT services. SEE CAO performs coordinated yearly, monthly, and daily auctions of cross-border electricity transmission rights throughout South East Europe.
The overall direction of travel is toward greater market coupling. The Energy Community’s Electricity Integration Package aims to bring Contracting Parties closer to the EU internal electricity market. However, progress remains uneven. By the end of 2025, only Serbia and Moldova had completed full transposition of the package, while the earliest market coupling for Contracting Parties was projected for 2028, subject to European Commission verification.
This timeline carries important implications for traders and investors. It confirms that Western Balkan market integration is progressing, but it will not happen overnight. Between today and full market coupling, the region will continue to experience a transition period characterized by both opportunity and complexity.
The EU’s transition to 15-minute day-ahead trading makes this evolution even more significant. On 30 September 2025, the European day-ahead electricity market shifted from hourly to 15-minute trading intervals. This change allows market prices to reflect expected generation and demand conditions more accurately, particularly in power systems with high levels of renewable energy.
For South East Europe, the move to 15-minute intervals changes the entire trading discipline. Hourly forecasting is no longer sufficient. Solar generation ramps, wind forecast deviations, demand fluctuations, hydro dispatch decisions, and battery optimization strategies must all be modeled on a quarter-hour basis. A trader may correctly predict the average hourly price yet still incur losses if quarter-hour imbalance exposure is mismanaged.
Market coupling will eventually reduce certain market inefficiencies, but it will not eliminate volatility. In many cases, deeper integration may actually reveal volatility more clearly. Coupling can improve the allocation of transmission capacity, but it cannot create flexibility where none exists. Likewise, 15-minute trading can sharpen price signals, but it cannot build storage facilities or expand transmission infrastructure.
The strategic conclusion is straightforward: SEE market coupling should be viewed as a long-term reform process rather than a single transformative event. It will narrow some price spreads, deepen liquidity, and reduce trading frictions. Nevertheless, during the transition period, market participants must continue operating across two realities—highly integrated EU markets and partially integrated Western Balkan markets.
The best-positioned participants will be those capable of combining three critical skills: trading the exchange screen, managing cross-border transmission exposure, and understanding the evolving regulatory framework. In South East Europe’s electricity market, success increasingly depends on mastering all three dimensions simultaneously.