1. Introduction

Offshore Carbon Capture and Storage (CCS) involves transporting captured carbon dioxide (CO₂) from industrial or power facilities through pipelines or other transport systems to offshore geological formations, where it is permanently stored. In the United Kingdom, offshore CCS is regulated through a combination of the Energy Act 2008, the Storage of Carbon Dioxide (Licensing etc.) Regulations 2010, offshore environmental-impact legislation, habitat protection rules, planning law, and Crown property rights. The regulatory objective is to ensure that geological storage is technically secure, environmentally acceptable and properly monitored throughout its operational and post-closure life.

2. Licensing Framework

The Energy Act 2008 establishes the principal licensing regime for offshore CO₂ storage. A person seeking to explore for or use a geological formation for long-term CO₂ storage must obtain the appropriate carbon dioxide storage licence. The detailed framework is supplemented by the Storage of Carbon Dioxide (Licensing etc.) Regulations 2010. The licensing regime covers exploration and appraisal, development and injection, monitoring, closure and post-closure responsibilities.

The North Sea Transition Authority (NSTA) acts as the principal licensing authority for offshore storage, subject to the statutory division of competence, including the role of Scottish Ministers for the territorial sea adjacent to Scotland. Offshore developers may also require a Crown Estate or Crown Estate Scotland lease, because the relevant seabed and storage rights involve Crown property interests.

3. Environmental Regulation and EIA

Offshore CCS infrastructure is subject to environmental controls designed to identify and mitigate impacts on marine ecosystems, seabed environments and protected sites. The offshore EIA regime requires assessment of significant environmental effects before relevant projects can proceed. Appropriate assessment may additionally be required where a proposal could affect protected European offshore marine sites or other protected habitats.

Environmental regulation therefore extends beyond the storage reservoir itself. CO₂ pipelines, platforms, wells, compressor facilities, seabed works and associated infrastructure may each engage different consenting requirements. Regulators can impose conditions concerning monitoring, environmental protection, emergency procedures and decommissioning.

4. Monitoring, Financial Security and Closure

An important characteristic of CCS regulation is that liability does not end when CO₂ injection stops. The regulatory framework requires monitoring and post-closure plans, financial security and regulatory oversight. The NSTA's functions include approving monitoring and post-closure arrangements, overseeing financial security, inspecting storage operations and reviewing, modifying or revoking licences or storage permits.

Under the existing framework, a closed storage site can ultimately return to State responsibility after the prescribed post-closure period, currently generally 20 years, subject to the applicable statutory conditions. This creates an important distinction between operator liability during the regulated period and potential long-term State responsibility.

5. Case Law

Case Name/Citation: R (HyNot Ltd) v Secretary of State for Energy Security and Net Zero & Anor [2025] EWHC 2644 (Admin).

Facts: The case concerned the HyNet Carbon Dioxide Transportation and Storage Project – Offshore, involving three geological storage sites beneath the East Irish Sea, designed to store approximately 109 million tonnes of CO₂. The claimant challenged governmental and NSTA decisions concerning environmental consent and storage development.

Legal Issue: The challenge concerned, among other matters, whether the authorities had adequately considered major accidents and disasters, consultation, cumulative climate effects and protected habitats.

Judgment: The High Court refused permission for judicial review. The court considered that the environmental assessment and consultation processes provided an adequate basis for decision-making and found the pleaded grounds unarguable.

Legal Principle/Ratio Decidendi: The case demonstrates that offshore CCS projects remain subject to rigorous environmental and administrative-law scrutiny, but the court will distinguish between a legally required assessment and demands for a particular substantive conclusion.

Significance: HyNot is particularly significant because it is directly concerned with offshore CO₂ transportation and geological storage, providing an important modern illustration of how the Energy Act, offshore EIA regime and judicial review interact.

Additional Case: R (Boswell) v Secretary of State for Energy Security and Net Zero [2025] EWCA Civ 669 concerned a gas-fired generating project incorporating CCS and examined the legal treatment of greenhouse-gas emissions in planning decision-making. The Court of Appeal's reasoning illustrates the importance of properly identifying the causal relationship between a development and its environmental effects.

6. Conclusion

Offshore CCS regulation in the UK is therefore a multi-layered legal system combining storage licensing, environmental assessment, habitat protection, monitoring, financial security, property rights and decommissioning obligations. Its central regulatory challenge is to enable large-scale carbon storage while ensuring that CO₂ leakage, marine environmental damage, accident risks and long-term liability are adequately controlled. The emerging HyNot litigation demonstrates that these requirements are increasingly becoming important issues of judicial scrutiny as the UK's offshore CCS infrastructure expands.