ENERGY LAW AND CROSS-BORDER SUPERGRID GOVERNANCE SYSTEMS

1. Introduction

A cross-border supergrid is a large interconnected electricity network linking several national or regional power systems through high-capacity transmission infrastructure, particularly high-voltage alternating-current and high-voltage direct-current interconnectors. Its purpose may include renewable-energy integration, electricity trading, security of supply, balancing, congestion management and sharing generation resources across jurisdictions.

Because electricity continuously moves across national boundaries, a supergrid cannot be governed effectively by one national regulator alone. Its legal framework must coordinate transmission system operators, national regulators, regional institutions, market operators and governments. In the European Union, Regulation (EU) 2019/943 establishes rules intended to facilitate integrated electricity markets and fair cross-border electricity exchanges.

2. Institutional Governance

Effective supergrid governance requires institutions capable of resolving issues extending beyond national borders. Within the EU, the Agency for the Cooperation of Energy Regulators (ACER) helps coordinate national regulatory authorities, while the European Network of Transmission System Operators for Electricity supports coordinated network planning and operation.

Regulation (EU) 2019/942 specifically gives ACER responsibilities concerning cross-border infrastructure and requires it to monitor new interconnector capacity and implementation of Union-wide network-development plans.

This institutional structure reduces the regulatory fragmentation that would arise if every state independently determined technical or market rules for the same interconnected network.

3. Cross-Border Capacity Allocation

A major legal issue concerns how limited transmission capacity between national systems should be distributed. Supergrid rules therefore regulate capacity calculation, bidding zones, congestion management, balancing and electricity-market coupling.

Regulation (EU) 2019/943 requires electricity-market structures progressively to remove barriers to cross-border electricity flows and promotes harmonised rules for interconnection capacity.

Common capacity-calculation methodologies are particularly important because one transmission system operator's decisions can affect available capacity, prices and security elsewhere in the interconnected system.

4. Interconnector Investment and Regulation

Supergrids require enormous capital investment. Legal frameworks must therefore determine who pays for interconnectors, how congestion income is used and how investors recover costs.

Article 63 of Regulation 2019/943 permits qualifying new direct-current interconnectors to receive temporary exemptions from certain regulatory obligations where specified conditions are satisfied, including circumstances in which investment risk is sufficiently high that the project would otherwise not proceed.

Such exemptions attempt to balance infrastructure investment incentives with competition and third-party-access principles.

5. System Security and Regional Coordination

A supergrid creates mutual dependence. A disturbance originating in one jurisdiction may propagate through interconnected networks. Legal governance must therefore establish common technical standards covering frequency control, balancing, outage coordination, emergency operation, cybersecurity and system restoration.

EU electricity law also permits network codes and guidelines concerning operational coordination among transmission system operators.

CASE LAW

Baltic Cable AB v Energimarknadsinspektionen, Case C-454/18 (2020)

Case Name/Citation: Baltic Cable AB v Energimarknadsinspektionen, Case C-454/18, EU:C:2020:189.

Facts: Baltic Cable operated an electricity interconnector between Sweden and Germany. A dispute arose concerning the treatment of congestion revenues generated by the cross-border infrastructure.

Legal Issue: Whether EU rules governing congestion revenue applied to an undertaking whose principal activity was operating a cross-border electricity interconnector.

Judgment: The Court of Justice held that the relevant cross-border electricity rules applied to such an operator. It also held that the national regulator had to permit appropriate use of congestion revenue so that the operator could function under financially acceptable conditions.

Legal Principle/Ratio: Cross-border interconnector operators fall within the regulatory architecture governing transmission capacity and congestion revenue, even where they do not operate an extensive domestic transmission network.

Significance: The case demonstrates that supergrid governance must reconcile cross-border market regulation with the economic viability of interconnector infrastructure.

Austrian Power Grid AG and Others v ACER, Case T-600/23

Facts: Transmission system operators challenged ACER measures establishing common methodologies for calculating day-ahead and intraday cross-zonal electricity capacity within the European Core capacity-calculation region.

Legal Issue: Whether ACER had lawfully exercised its regulatory powers when establishing regional methodologies governing cross-border transmission capacity.

Judgment: The General Court partially annulled the relevant Board of Appeal decision concerning ACER's methodologies.

Legal Principle/Ratio: Supranational regulators exercising powers over cross-border grid methodologies must remain within their statutory authority and comply with the applicable regulatory framework.

Significance: The case illustrates the increasing judicial scrutiny accompanying regionalised supergrid governance and the importance of clearly allocating authority between TSOs, national regulators and ACER.

6. Conclusion

Cross-border supergrid governance converts electricity transmission from a predominantly national activity into a system of shared regulatory responsibility. Effective governance requires coordinated network planning, harmonised technical standards, transparent capacity allocation, investment rules, congestion management and supranational regulatory oversight. Cases such as Baltic Cable and Austrian Power Grid v ACER demonstrate that courts increasingly determine how regulatory powers, revenues and responsibilities should be distributed within interconnected electricity systems. As renewable generation and long-distance transmission expand, coherent cross-border governance will become increasingly important for maintaining reliable, competitive and legally accountable electricity markets.