NATIONALLY SIGNIFICANT INFRASTRUCTURE PROJECTS (NSIPs) IN ELECTRICITY LAW

1. Introduction

In UK electricity law, Nationally Significant Infrastructure Projects (NSIPs) are major infrastructure developments considered sufficiently important to require a special national planning and consent regime. The principal statutory framework is the Planning Act 2008, subsequently amended, including by the Planning and Infrastructure Act 2025. The regime covers major energy projects such as certain generating stations and high-voltage overhead electricity lines.

The NSIP system seeks to combine efficient infrastructure delivery with environmental protection, public participation, energy security, climate policy and administrative-law accountability.

2. Electricity Projects Qualifying as NSIPs

Section 14 of the Planning Act 2008 identifies categories of nationally significant infrastructure. Sections 15 and 16 contain specific rules concerning electricity infrastructure.

Under the statutory framework, qualifying generating stations and certain overhead electric lines may constitute NSIPs. The Act specifies capacity and geographical requirements; for example, its electricity provisions include thresholds concerning generating capacity and provide that relevant overhead electric lines generally must operate at 132 kV or above, subject to statutory exceptions and territorial rules.

These provisions place strategically important electricity infrastructure within a nationally coordinated planning system rather than relying solely upon ordinary local planning procedures.

3. Development Consent Orders

An NSIP generally requires authorisation through a Development Consent Order (DCO). The DCO mechanism is intended to provide an integrated consent process for complex infrastructure.

Applications are examined through the Planning Act procedure, after which the relevant Secretary of State determines whether development consent should be granted. The decision must operate within the applicable statutory framework and relevant National Policy Statements (NPSs).

For electricity projects, energy National Policy Statements are especially important because they establish government policy concerning infrastructure need and provide the framework against which particular projects are assessed.

4. Environmental and Climate Considerations

Electricity NSIPs may have substantial effects on landscapes, biodiversity, communities and greenhouse-gas emissions. Consequently, environmental assessment requirements form an important part of the development-consent process.

Decision-makers must also address legally relevant climate considerations. However, courts generally distinguish between reviewing the lawfulness of the decision-making process and substituting judicial preferences for the infrastructure judgment entrusted by legislation to the responsible authority.

5. Case Law – ClientEarth v Secretary of State for Business, Energy and Industrial Strategy [2021] EWCA Civ 43

Case Name/Citation: ClientEarth v Secretary of State for Business, Energy and Industrial Strategy [2021] EWCA Civ 43.

Facts: Drax Power Ltd proposed two large gas-fired generating units at Drax Power Station in North Yorkshire. The project, with generating capacity potentially reaching approximately 3,800 MW, constituted an NSIP. The examining authority recommended refusing consent, but the Secretary of State disagreed and granted the DCO in 2019. ClientEarth challenged that decision.

Legal Issue: The central questions concerned whether the Secretary of State had correctly interpreted the applicable energy National Policy Statements when assessing the project's contribution to electricity infrastructure need, greenhouse-gas emissions, and the statutory decision-making requirements of the Planning Act 2008.

Judgment: The Court of Appeal dismissed ClientEarth's appeal and upheld the legality of the Secretary of State's decision.

Legal Principle/Ratio Decidendi: National Policy Statements have substantial legal importance in determining NSIP applications. Their interpretation must reflect the statutory Planning Act framework, while the Secretary of State retains the policy judgment allocated by that framework when weighing infrastructure need against adverse impacts.

Significance: The case demonstrates that an examining authority's recommendation is important but does not itself determine the final outcome. The Secretary of State may reach a different conclusion provided that the statutory framework and applicable policies are lawfully applied.

6. Broader Judicial Principle

The Supreme Court has described the Planning Act 2008 as establishing a more efficient method of obtaining planning and related approvals for nationally significant projects, including power stations, within a policy framework approved by Parliament. It has also recognised that section 158 provides specific statutory protection concerning nuisance for activities authorised by a DCO, subject to the statutory conditions.

This illustrates the distinctive legal consequences that can follow from NSIP authorisation.

7. Recent Development – Planning and Infrastructure Act 2025

The Planning and Infrastructure Act 2025 introduced further reforms to the NSIP system. Its infrastructure provisions address matters including National Policy Statement review, DCO applications, examinations, legal challenges and changes to development consent orders. Separate provisions concern electricity-network connections and strategic management of connection arrangements.

8. Conclusion

NSIPs are therefore central to modern UK electricity law. They provide a national legal mechanism for authorising strategically important generation and transmission infrastructure, while integrating planning policy, environmental assessment, climate considerations and public participation. ClientEarth demonstrates that courts supervise the legality of electricity-infrastructure decisions while recognising the policy and technical judgments that Parliament has entrusted to designated decision-makers.