On 10 September 2026, the UK government chose continuity in renewable diesel supply over a new trade barrier. The Trade Remedies Authority said hydrotreated vegetable oil, or HVO, biodiesel imported from the United States was subsidised and had injured UK industry, and it recommended a fixed duty of £258.10 to £266.68 per tonne. The Secretary of State then rejected that recommendation, meaning no definitive anti-subsidy duty will be applied. (gov.uk) The notice took effect on 11 September 2026 and instructed HM Revenue & Customs to stop registering those imports for a possible remedy. The case covers HVO, often sold as renewable diesel or green diesel, and it explicitly excludes sustainable aviation fuel. (gov.uk)

For climate and transport readers, this is more than a dry trade ruling. Department for Transport figures show renewable fuels made up 8% of all road and non-road mobile machinery fuel supplied in the UK in 2024, with average lifecycle greenhouse gas savings of 80% against fossil fuel. HVO alone accounted for 21% of verified renewable fuel supply, reaching 784 million litres equivalent in 2024, the latest complete annual dataset; the 2025 figures published so far remain provisional and incomplete. (gov.uk) That helps explain why ministers were wary of adding cost into this market. Zemo Partnership says renewable diesel is already being used in heavy-duty vehicles and non-road machinery as a near-term way to cut emissions where electrification will take longer, while the Climate Change Committee says biofuels can still play a sensible role in the remaining conventional fleet. (zemo.org.uk)

The ruling turns on a distinction that often gets lost in trade coverage. The TRA concluded that a remedy was justified on subsidy and injury grounds, yet its own economic interest test found that imposing the measure would not be in the UK’s economic interest. In the formal notice, ministers said they rejected the tariff because that test had been failed by a significant margin. (gov.uk) In practical terms, that suggests the government saw wider costs to fuel users and the economy as outweighing the case for shielding one part of the biofuel chain. That reading fits a country which, by the TRA’s own account, has an established FAME biodiesel industry but no dedicated HVO production of its own. (gov.uk)

UK biodiesel producers are unlikely to welcome that outcome. The TRA’s final finding says subsidised US HVO caused injury to UK industry, and the official background notes that while Britain has an established FAME production base, it still lacks dedicated HVO capacity. The investigation was launched on 17 March 2025, with 2024 used as the investigation period and 2021 to 2024 as the injury period. (gov.uk) There is history here too. In 2022, the government accepted a TRA recommendation to keep trade protections on FAME biodiesel from the US and Canada while revoking them for HVO, arguing at the time that open HVO supply would benefit parts of the UK transport economy. This week’s decision keeps that broad split in place: protection for domestic FAME remains one policy aim, but imported HVO is still being treated as a fuel the market needs. (gov.uk)

The bigger environmental question is not simply where the fuel comes from, but what it is made from. Under the RTFO, renewable fuel must meet minimum greenhouse gas savings and must not come from land with high biodiversity value or carbon stock unless strict criteria are met. In 2024, the Department for Transport says 77% of all verified renewable fuel supplied to the UK came from waste feedstocks, and used cooking oil alone accounted for 46% of the total. (gov.uk) That is encouraging, but it is not the whole picture. The Department for Transport also notes that the RTFO works on a mass-balance basis, so the actual feedstock mix can differ from what is reported in the statistics, while Transport & Environment argues that waste oils and fats are limited in supply and face rising competition from both HVO and aviation fuel. Keeping imports open may help decarbonisation in the short run, but it makes traceability and feedstock quality even more important. (gov.uk)

The policy gap is now plain. The UK is relying on imported HVO to help cut emissions in parts of transport and machinery that are hard to clean up quickly, while offering no domestic HVO production base to balance supply security, industrial strategy and sustainability standards. Zemo Partnership says the UK imports HVO from Europe, Asia and, more recently, the United States. (gov.uk) If ministers want this decision to look like climate strategy rather than a one-off trade call, the next step is clear. The UK needs tougher public reporting on feedstocks, quicker support for advanced renewable diesel made from harder-to-fake wastes and residues, and a firmer view on where scarce bio-based fuels should be used first. The Climate Change Committee says sustainable bioenergy is limited and should be prioritised, while Zemo points to emerging renewable diesel pathways using agricultural and forestry residues. (theccc.org.uk)

For now, the market has a short-term answer. US HVO can continue entering the UK without a new anti-subsidy duty, and HMRC’s registration requirement ended on 11 September 2026. That should ease immediate supply concerns for buyers of renewable diesel, but it does not settle the harder question of how the UK wants to decarbonise liquid fuels fairly, credibly and at pace. (gov.uk) The real test is simple: does this decision buy time for cleaner transport, or does it postpone the tougher work on domestic production, feedstock assurance and smarter use of scarce biofuels? Ministers have kept the fuel flowing. They now need to show the strategy behind it. (gov.uk)