UK ENERGY LAW AND INTERNATIONAL ENERGY COOPERATION

Concept and Importance

International energy cooperation refers to the legal, regulatory and institutional arrangements through which the United Kingdom works with other states, international organisations and regional energy markets to improve energy security, cross-border electricity trade, decarbonisation, infrastructure investment and technological development. Because the UK electricity system is physically connected with neighbouring European systems through interconnectors, domestic energy law cannot operate entirely in isolation.

International cooperation is particularly important for renewable integration, offshore wind, electricity balancing, emergency supply, nuclear safety, hydrogen development and cross-border infrastructure.

UK–EU Energy Cooperation

Following Brexit, the principal framework governing UK–EU energy relations is the EU–UK Trade and Cooperation Agreement (TCA). Its Energy Title establishes cooperation concerning electricity and gas markets, security of supply, renewable energy and cross-border infrastructure.

The UK Government’s Strategy and Policy Statement confirms that the TCA provides a framework for developing efficient electricity trading arrangements over interconnectors and for cooperation concerning North Seas offshore grids, decarbonisation and security of supply. Ofgem also has a role in cooperation with European energy regulators.

In June 2025, the UK and EU reaffirmed their intention to continue the Energy Title through successive decisions, demonstrating the continuing strategic importance of energy cooperation after Brexit.

Electricity Interconnectors and Cross-Border Infrastructure

Electricity interconnectors allow power to move between Great Britain and neighbouring electricity markets. They can reduce system costs, strengthen security of supply and assist the integration of variable renewable electricity.

The Energy Act 2023 expanded the regulatory framework by establishing multi-purpose interconnectors, which can combine cross-border electricity transmission with connections to offshore generation. Such infrastructure requires licensing by Ofgem. The legislation reflects the growing connection between domestic electricity regulation and international infrastructure planning.

International coordination is therefore necessary for capacity allocation, network codes, market coupling, system balancing and emergency electricity flows.

Northern Ireland and the Single Electricity Market

Northern Ireland provides a particularly important example of legally integrated international electricity governance. The Single Electricity Market operates across Northern Ireland and the Republic of Ireland.

Post-Brexit arrangements preserve important elements of EU electricity law necessary for that market to function. This demonstrates how international legal cooperation may be essential where electricity systems are technically and economically interconnected across national borders.

CASE LAW — Germany v Poland, Case C-848/19 P, EU:C:2021:598

Facts: The dispute concerned the OPAL gas pipeline, connected with Nord Stream 1. Poland challenged a European Commission decision permitting increased use of pipeline capacity, arguing that its consequences for the energy security of other Member States had not been adequately considered.

Legal Issue: Whether the principle of energy solidarity under Article 194(1) TFEU constituted a legally enforceable principle governing European energy decision-making.

Judgment: The Court of Justice upheld the annulment of the Commission decision and confirmed that energy solidarity is a legally binding principle against which EU energy measures may be reviewed.

Legal Principle/Ratio: Energy policy cannot be assessed exclusively by reference to one state's interests. Decision-makers must consider consequences for other participating states and the wider interconnected energy system.

Significance: Although the UK is no longer an EU Member State, the case demonstrates the legal logic underlying international energy cooperation: interconnected infrastructure creates reciprocal security and regulatory responsibilities.

CASE LAW — R (Friends of the Earth Ltd) v Heathrow Airport Ltd [2020] UKSC 52

Facts: Environmental organisations challenged the Airports National Policy Statement supporting Heathrow expansion, arguing that the Government had failed properly to consider the UK's commitments under the Paris Agreement.

Legal Issue: Whether failure to treat the Paris Agreement in the manner argued by the claimants rendered the national policy statement unlawful.

Judgment: The Supreme Court allowed Heathrow Airport's appeal and held that the Secretary of State had not acted unlawfully when preparing the policy statement.

Legal Principle/Ratio: International agreements and governmental commitments may influence domestic policymaking, but their precise domestic legal effect depends upon the relevant statutory framework and whether those obligations have been incorporated into domestic law.

Significance: The case illustrates the relationship between international climate cooperation and UK domestic energy and infrastructure governance.

Energy Investment and International Treaties

International energy cooperation also concerns investment protection. The UK historically participated in the Energy Charter Treaty, which protected certain cross-border energy investments. However, the Government announced withdrawal in 2024 after modernisation negotiations failed; withdrawal subsequently took effect following the treaty procedure.

Conclusion

UK energy law increasingly operates through international networks rather than purely national regulation. The TCA, electricity interconnectors, the Single Electricity Market, offshore energy cooperation, climate agreements and international investment rules demonstrate that energy security and decarbonisation depend upon legal coordination between jurisdictions. International energy cooperation therefore forms an essential component of modern UK electricity governance, combining national regulatory sovereignty with the practical requirements of an interconnected energy system.