Europe’s seventy-percent cross-zonal electricity rule is not a bureaucratic exercise. It is a structural redefinition of how power markets in Europe are meant to behave. The principle is blunt: at least seventy percent of available cross-border transmission capacity must be made open for electricity trading. This obligation operationalises a strategic truth — that modern electricity systems cannot afford to behave like disconnected islands when decarbonisation, renewable intermittency and industrial competitiveness now depend on deeper regional alignment than ever before. For South-East Europe, this rule is not simply another compliance checkbox. It is one of the most consequential tests of political maturity, regulatory discipline and strategic seriousness the region has ever faced.
The core idea behind the rule is simple. Electricity systems become safer, more efficient and more competitively priced when they are allowed to breathe across borders. Renewables fluctuate with wind and sun, so balancing must become continental rather than purely national. Price pressure in one system is mitigated when power can flow from another. Infrastructure is justified more efficiently when shared dynamically rather than constrained artificially. Europe is not asking governments to trust ideology; it is asking them to trust engineering, markets and evidence.
South-East Europe, however, approaches this obligation with a deeply layered history. The region’s energy sectors were built around state control, politically sensitive ownership structures and sovereignty reflexes that still frame decision-making today. Transmission operators worry about reliability exposure. Governments worry about political accountability if foreign power dominates their balancing system. Regulators frequently walk a cautious line between European pressure and domestic hesitation. These instincts are historically understandable. They are also increasingly misaligned with the electricity world the region now lives in.
Different SEE countries face this rule from very different positions. Serbia represents the most powerful example of both opportunity and hesitation. On the one hand, Serbia stands physically and strategically in the middle of the regional grid. On the other, it is still psychologically attached to a vision of electricity sovereignty rooted more in national control than in network confidence. Its economy increasingly depends on predictable electricity realities. Investors, manufacturers and households cannot endure repeated price and risk instability. The Trans-Balkan Corridor strengthens its infrastructure posture. Whether it properly meets the seventy-percent obligation will show whether Serbia is prepared to accept that real sovereignty in modern electricity lies in resilience, not isolation.
Montenegro approaches the obligation from a cleaner and more pragmatic place. With strong European alignment traditions and a demonstrated capacity to function as a responsible market actor, meeting the seventy-percent rule reinforces its positioning rather than threatening it. Montenegro benefits directly when Europe rewards well-governed, open electricity systems — and the rule formalises that reward.
Greece again represents the reality of rapid transition. It has already moved decisively toward a new power future, and its challenge is ensuring infrastructure, trading systems and operational rules are robust enough to allow surplus renewable power to truly become a regional stabiliser rather than a domestic balancing problem. For Greece, compliance is not only about openness; it is about ensuring the physical and regulatory capacity to sustain that openness confidently.
Romania is naturally shaped for leadership in this discussion. System scale, nuclear strength and renewable acceleration position it as a foundational stabilising hub. But Romania’s recurring governance hesitation still remains the unknown factor. If Romania embraces full cross-border participation decisively and consistently, much of SEE will find itself anchored around a stronger centre of gravity. Bulgaria faces a similar truth. It has capacity and strategic importance. Whether it becomes a stabilising exporter or a hesitant actor depends largely on political clarity and regulatory courage.
Hungary, with strong import reliance and periodic exposure to very high electricity prices, has perhaps the most obvious practical need to support open cross-border regimes. But like others, it shapes its decisions within broader national strategic considerations. Bosnia and Herzegovina and North Macedonia face governance and vulnerability realities respectively. Bosnia must first solve political coherence before it can meaningfully guarantee regional compliance behaviour, while North Macedonia’s future depends substantially on whether others open, because its survival requires it.
The seventy-percent rule does not politely request alignment. It forces a choice. Either South-East Europe integrates properly and enters a future of more predictable, efficient and resilient electricity, or it remains stuck in a halfway reality — part of Europe legally, separate from Europe practically, more expensive and less competitive than it should be. Europe has set the rules. Now it is South-East Europe that needs to decide whether it wants a modern electricity future or another cleverly justified delay.