SIZEWELL C AND HINKLEY POINT C LEGAL FRAMEWORKS

1. Introduction

Sizewell C in Suffolk and Hinkley Point C in Somerset are major UK nuclear projects built around two European Pressurised Reactor units, each designed to provide approximately 3.2 GW of generating capacity. Although both projects operate within the same general nuclear-safety and planning framework, their financing structures differ significantly. Hinkley Point C relies principally on a long-term Contract for Difference (CfD), whereas Sizewell C is financed through the Regulated Asset Base (RAB) model under the Nuclear Energy (Financing) Act 2022.

2. Planning and Development Consent

Both projects constitute Nationally Significant Infrastructure Projects under the Planning Act 2008. Accordingly, development requires a Development Consent Order rather than ordinary local planning permission.

Hinkley Point C received consent through the Hinkley Point C (Nuclear Generating Station) Order 2013, which authorises construction, operation and associated infrastructure.

Sizewell C received development consent through the Sizewell C (Nuclear Generating Station) Order 2022, made by the Secretary of State under section 114 of the Planning Act 2008.

Planning decisions must also comply with environmental assessment, habitats protection, water-resource and consultation requirements.

3. Nuclear Safety and Licensing

Construction and operation of nuclear installations require a nuclear site licence under the Nuclear Installations Act 1965. The Office for Nuclear Regulation (ONR) assesses site suitability, organisational capability and the nuclear safety case.

Sizewell C received its nuclear site licence on 7 May 2024. The licence does not itself authorise unrestricted construction: ONR retains regulatory control over important stages of nuclear-safety-related construction, commissioning and operation.

Environmental permits from the Environment Agency and other regulatory permissions operate separately from the nuclear licence.

4. Hinkley Point C Financing Framework

Hinkley Point C is supported by a 35-year CfD. The contractual strike price is generally £92.50/MWh in 2012 prices, with provisions linking the price to Sizewell C-related circumstances. When the reference market price is below the strike price, support is paid to the generator; when it exceeds the strike price, the generator generally pays back the difference.

The framework also includes a Secretary of State Investor Agreement and government-backed arrangements addressing specified political shutdown and financing risks.

5. Sizewell C Financing Framework

Sizewell C instead uses the nuclear RAB model created by the Nuclear Energy (Financing) Act 2022. Under this framework, the project receives regulated revenue, including during construction, with Ofgem exercising economic regulatory oversight.

The model transfers part of construction and financing risk across investors and consumers in order to reduce the cost of capital compared with financing structures requiring developers to fund the entire construction period before receiving revenue. The government confirmed Sizewell C's final investment decision on 22 July 2025.

6. Case Law

Together Against Sizewell C Ltd v Secretary of State for Energy Security and Net Zero [2023] EWCA Civ 1517

Facts: Campaigners challenged the Sizewell C Development Consent Order, particularly concerning the proposed permanent supply of potable water and its effects on protected habitats.

Legal Issue: Whether the Secretary of State unlawfully failed to undertake an appropriate assessment under the Conservation of Habitats and Species Regulations 2017.

Judgment: The Court of Appeal rejected the challenge.

Legal Principle/Ratio: A decision-maker must lawfully assess environmental effects of the project requiring consent, but whether another proposal constitutes part of the same project or a sufficiently connected plan depends upon the statutory and factual context.

Significance: The case demonstrates the intensive environmental-law scrutiny applicable to major nuclear development consent.

Republic of Austria v European Commission, Case C-594/18 P

Facts: Austria challenged European Commission approval of UK State aid supporting Hinkley Point C through the CfD, governmental protections and credit guarantee.

Legal Issue: Whether the financial support was compatible with EU State-aid law.

Judgment: The Court of Justice upheld the Commission's approval.

Legal Principle/Ratio: Article 107(3)(c) TFEU could permit State aid facilitating development of nuclear electricity generation where compatibility requirements were satisfied.

Significance: The case established the legality, under the then-applicable EU State-aid framework, of Hinkley Point C's exceptional financing structure.

7. Conclusion

The two projects share a common framework of Planning Act consent, ONR licensing, environmental regulation, decommissioning obligations and regulatory supervision, but differ fundamentally in financing. Hinkley Point C represents the CfD model, while Sizewell C represents the UK's transition toward RAB-financed nuclear development, demonstrating an evolving legal allocation of construction, market and investment risk.