Örsted braces for landmark UK Supreme Court ruling on wind farm survey tax with sector-wide implications for renewable energy project costs
Örsted, the Danish offshore wind developer, is awaiting a landmark judgment from the UK Supreme Court — due to be handed down on 15 April 2026 — in a long-running tax dispute with HM Revenue & Customs (HMRC), the UK's tax authority. The case concerns Örsted's West of Duddon Sands offshore wind project (108 turbines off Barrow-in-Furness) and turns on whether pre-construction survey costs qualify as expenditure 'on the provision of plant' for capital allowances — the UK's tax-relief regime for capital expenditure on plant and machinery. HMRC appealed a lower court ruling in Örsted's favour, bringing the matter to the Supreme Court. The outcome will establish the tax treatment of development-phase survey expenditure not only for offshore wind, but for all types of renewable energy projects — including solar farms — during their pre-construction phase. Örsted disclosed in its 2025 annual report that it has set aside provisions in anticipation of the ruling. The judgment is directly relevant to the economics of the UK's offshore wind pipeline: survey costs are a material element of pre-final investment decision (pre-FID) expenditure, and a ruling against Örsted would increase effective tax costs for wind and solar developers, potentially affecting project viability calculations and contract-for-difference (CfD — a government revenue support mechanism for renewable generators) bid pricing.
Why this matters
A Supreme Court ruling on the tax deductibility of development-phase survey costs is a structural question for the entire UK renewable energy sector, not just Örsted. If HMRC prevails, developers will face higher effective pre-FID tax costs, squeezing project returns and potentially reducing appetite for offshore wind bids in future CfD auctions. Law firms advising on project finance for offshore wind will need to revisit tax structuring assumptions in financial models and may face client requests to review existing deduction claims. The case also intersects with the broader DESNZ (Department for Energy Security and Net Zero) agenda to accelerate offshore wind capacity, creating political as well as legal pressure on the outcome. Energy and tax practices will be most directly affected, but project finance teams advising lenders on debt structuring for new wind developments will also need to factor in revised tax assumptions.
On the Ground
A trainee supporting the legal team monitoring this judgment would prepare a licence condition summary identifying all Örsted project entities affected, draft a regulatory filing coordination note for any HMRC response required post-judgment, and assist in updating due diligence reports on comparable offshore wind projects where the same tax treatment has been assumed.
Interview prep
Soundbite
A ruling against Örsted effectively raises the cost of building UK offshore wind — and forces project finance lawyers to reprice CfD bid economics.
Question you might get
“How does the tax treatment of pre-construction development costs affect the financial modelling for an offshore wind project seeking debt finance, and what does a lender's legal team need to check?”
Full answer
The UK Supreme Court is handing down its judgment today in Örsted's capital-allowances dispute with HMRC over whether development-phase survey costs at the West of Duddon Sands offshore wind project qualify as expenditure 'on the provision of plant'. The ruling will set precedent for all renewable energy developers in the UK — solar and onshore wind included — determining whether pre-construction survey expenditure counts as capital-allowances-eligible expenditure on plant for offshore wind. If HMRC wins, the effective tax cost of developing new wind capacity rises, which feeds directly into the viability of bids in CfD auctions and project finance modelling. The timing is significant: the UK government has committed to major offshore wind expansion, and this ruling creates tension between fiscal policy and energy security objectives. Law firms will face immediate demand for tax structuring reviews and updated project finance advice.
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