Of all the decarbonisation options available to a truck fleet today, hydrotreated vegetable oil - HVO - is the least disruptive. It is a paraffinic renewable diesel made from waste fats, oils and greases, it meets the EN 15940 fuel standard, and in most modern diesel engines it requires no modification, no new tanks and no driver retraining. You drain the diesel, pour in HVO, and drive. That simplicity explains both its rapid uptake and the questions every fleet should ask before switching.
HVO is produced by hydrotreating waste lipids - used cooking oil, animal fats, residues - into a fuel chemically similar to fossil diesel but distinct from conventional biodiesel (FAME). The distinction matters operationally. FAME biodiesel carries the storage stability, cold-weather and blending-limit problems fleets know from B7 and B20; HVO is oxidation-stable, stores well, performs in the cold and can be used neat at 100% or blended at any ratio with ordinary diesel. Most major truck manufacturers approve HVO for current engines, though the approval is per engine family - checking the manufacturer’s position for your specific vehicles is a pre-switch essential, not a courtesy.
The tax treatment is the fact that surprises most fleets: there is no fuel duty break for HVO. The government’s fuel duty guidance is explicit - if a substitute or additive will be used as road fuel in a diesel engine, you pay the rate for diesel for road use. HVO therefore carries the same 52.95 pence per litre duty as fossil diesel, plus VAT on top. The environmental benefit does not arrive through the tax system; it arrives through the fuel’s carbon intensity, and you pay a pump premium for it.
That premium is the central commercial question. HVO typically costs more per litre than diesel, varies with feedstock markets, and delivers roughly similar fuel economy. The business case rests on the value placed on the emissions reduction - by your own net-zero commitments, by customers writing carbon requirements into contracts, or by schemes that reward renewable fuel use - rather than on fuel cost savings, which generally do not exist.
The policy engine behind renewable fuels in the UK is the Renewable Transport Fuel Obligation. The RTFO requires suppliers of transport fuel to meet an annual obligation for the supply of sustainable low carbon fuel, operating as a certificate-trading mechanism: certificates are issued for the supply of eligible low carbon fuel, and suppliers owning and supplying 450,000 litres or more of relevant transport fuel in an obligation year must register under the scheme.
For a haulier buying HVO at the pump or in bulk, the certificates stay with the supplier - but the sustainability documentation follows the fuel. Reputable HVO supply comes with proof of sustainability under the RTFO framework: feedstock declarations, chain-of-custody records and greenhouse gas saving figures. That paperwork is what turns ‘we run HVO’ into a defensible carbon claim in a customer tender. Ask for it before the first delivery, and file it with the same care as any compliance document.
HVO’s attraction is a large reduction in lifecycle greenhouse gas emissions - waste-derived HVO delivers savings of the order of 80 to 90 per cent against fossil diesel on the standard RTFO calculation basis - plus modest reductions in some tailpipe pollutants. The caveats are equally important. The saving depends on feedstock: waste-derived fuel scores far better than crop-derived. Tailpipe NOx benefits are small and disputed; the big win is lifecycle carbon, not local air quality. And HVO is a bridge, not a destination - supply of genuine waste feedstocks is finite, and the long-term trajectory for heavy trucks still points toward electrification and other zero-emission options.
Fleets that switch successfully do five things: confirm manufacturer approval per engine family; secure sustainability documentation with every consignment; trial on a subset of vehicles with fuel consumption and driver feedback tracked; review storage - HVO can share diesel infrastructure, but a clean tank start avoids contamination questions; and lock the carbon accounting method with whoever reports the fleet’s emissions, so the benefit is claimed once, correctly, and with evidence. Do that and HVO is the fastest meaningful carbon cut a diesel fleet can make this year - bought with a fuel premium, not an engineering project.
As carbon clauses spread through freight contracts, the fleet running HVO becomes a claim customers test. Expect: which feedstocks, what certified saving, does the documentation cover every litre, and is the claim double-counted with the supplier’s own reporting? The answers live in the sustainability paperwork collected at purchase - which is why the unglamorous discipline of filing every consignment’s proof of sustainability is the difference between a marketing line and an auditable fact.