UK Supreme Court ruling in Ørsted's tax dispute with HMRC reshapes capital allowances framework for offshore wind projects, threatening viability of some developments
The UK Supreme Court has ruled against Danish offshore wind developer Ørsted in its tax dispute with HMRC (His Majesty's Revenue and Customs), delivering a judgment that resolves longstanding uncertainty over the scope of capital allowances — a form of tax relief that allows businesses to deduct the cost of qualifying capital assets from taxable profits — for large energy and infrastructure projects. The ruling provides what commentators at law firm Stewarts describe as 'welcome certainty but an unwelcome outcome' for the offshore wind sector. By clarifying the boundaries of capital allowances eligibility for offshore energy infrastructure, the judgment affects how future projects are structured, how costs are categorised between capital and revenue expenditure, and critically, how contracts between developers, contractors, and supply chain participants allocate the tax risk that flows from that categorisation. The practical implications are acute: some projects whose financial models assumed a broader scope of capital allowances relief may no longer be economically viable on their current terms. Developers and their advisers will need to revisit existing project documentation to assess exposure, and new projects will require contract structures that explicitly address the revised tax treatment. The ruling is likely to prompt renegotiation of contractor agreements where the allocation of tax risk was not definitively settled. For the UK offshore wind sector — a critical part of the government's clean energy target — the judgment arrives at a sensitive moment, with several large-scale developments in advanced planning stages.
Why this matters
A Supreme Court ruling on capital allowances for offshore energy infrastructure is a landmark moment for the UK project finance and energy tax practice. The immediate demand is for tax and energy lawyers to audit existing project documentation — PPA (power purchase agreements), EPC (engineering, procurement and construction) contracts, and financing documents — to identify where the tax risk allocation is now misaligned with the Supreme Court's definition of qualifying expenditure. Lenders with existing project finance facilities secured against offshore wind assets will also need to reassess their financial models, potentially triggering material adverse change assessments or covenant discussions. For new projects, the ruling functions as a hard constraint on financial model assumptions, likely increasing the cost of equity and debt capital for affected developments.
On the Ground
A trainee on an offshore wind project finance mandate would assist with reviewing planning permission and licence condition summaries to identify capital expenditure items affected by the ruling, draft due diligence notes comparing existing contract tax risk allocation clauses against the Supreme Court's new framework, and coordinate with external tax counsel on grid connection agreement analysis.
Interview prep
Soundbite
When a Supreme Court ruling shifts capital allowances eligibility, every existing project finance model in the sector needs stress-testing.
Question you might get
“How would you advise a project finance lender whose offshore wind loan facility was structured on the basis of capital allowances relief that the Supreme Court has now restricted?”
Full answer
The UK Supreme Court ruled against Ørsted in its capital allowances dispute with HMRC, clarifying the scope of tax relief available for offshore wind infrastructure in a judgment that carries direct financial consequences for project developers. The ruling affects cost categorisation, contract risk allocation, and financial model assumptions across the sector — with some projects potentially rendered unviable on existing terms. For project finance lawyers, the immediate task is reviewing existing EPC contracts and loan agreements to identify misaligned tax risk allocations, while new transactions will need to build the ruling's implications into their foundational documents. The broader context is the UK government's clean energy ambitions, which depend on offshore wind economics remaining attractive to private capital despite this tighter tax treatment.
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