10 October 2026
Can you use red diesel in a generator?
Since April 2022 most UK businesses can no longer use red diesel in generators. Here's who still can, and what to check.
Red diesel is rebated gas oil — diesel with lower duty, dyed red so it can be identified. Mechanically, a diesel generator runs on it just the same. The question is whether you're allowed to.
What changed in 2022
From 1 April 2022 the UK removed the right to use red diesel for most businesses, including construction and most commercial generator use. Those users must now use white (full-duty) diesel.
Who can still use it
A limited list of uses kept the entitlement, including agriculture, horticulture, fish farming and forestry, rail, and non-commercial heating. Whether your generator qualifies depends on what it powers and why.
Check before you fill up
Using red diesel when you're not entitled can lead to penalties and seizure. Check the current HMRC guidance on red diesel for your exact use before buying fuel.