A pump appears on the forecourt labelled XTL, or HVO100, or "renewable diesel". It costs a little more, it claims a much smaller carbon footprint, and the attendant says it goes straight in. Sometimes that is true. Sometimes it is not, and the difference is not a matter of opinion: it is written into two separate European standards. This is the part almost nobody explains at the roadside.
Two very different things share one name
HVO stands for hydrotreated vegetable oil. It is made by treating fats and oils with hydrogen until what comes out is, chemically, a paraffinic hydrocarbon, not a fatty acid methyl ester, which is what ordinary biodiesel (FAME) is. That chemistry difference is why HVO behaves so much more like conventional diesel than biodiesel does.
But HVO reaches your tank by two entirely different routes, and drivers routinely conflate them.
Route one: as a blend component in ordinary diesel. The EN 590 specification permits non-petroleum hydrocarbons (hydrotreated vegetable oil, GTL, BTL, or co-processed streams) in unlimited proportions, provided the finished fuel still meets EN 590. You are very possibly already burning some. It is not labelled, it needs no approval from anybody, and it changes nothing for you.
Route two: as a fuel in its own right. HVO100 sold neat is not EN 590 diesel. It is certified under a separate standard, EN 15940, for paraffinic diesel fuel from synthesis or hydrotreatment. This is the one that carries the XTL label on the nozzle, and the one where the question of approval actually arises.
The sentence worth remembering: paraffinic diesel does not meet EN 590 requirements: principally because its density is lower. Not "it is a variant of EN 590", not "it is EN 590 made from plants". A different specification, deliberately written because the fuel does not fit inside the old one.
What the numbers actually say
EN 15940 defines two classes, and they are not interchangeable:
Class A: cetane number minimum 71.0, density 765.0–800.0 kg/m³, sulphur maximum 5 mg/kg, total aromatics maximum 1.1% m/m.
Class B: cetane number minimum 51.0, density 780.0–810.0 kg/m³, sulphur maximum 5 mg/kg.
Set that beside EN 590 diesel: cetane minimum 51.0, sulphur maximum 10.0 mg/kg, FAME up to 7.0% under the standard.
Three things fall out of that comparison. Class A ignition quality is dramatically higher: a cetane floor of 71 against 51. Sulphur is halved. And there is no FAME at all in the paraffinic fuel, which removes the component most associated with poor storage stability and cold-weather trouble.
The catch is density. Diesel is metered by volume and sold by the litre, but an engine wants a mass of fuel. A lower-density fuel delivers slightly less energy per litre through an injection system calibrated for the denser stuff. In practice this shows up as a small consumption penalty rather than as a fault, but it is exactly the sort of parameter an engine manufacturer cares about, and it is why approval is a real question rather than a formality.
Approval: the honest position
Here the reliable published detail thins out, so it is worth marking clearly where certainty ends.
What is documented is that EN 15940 fuels can serve as a drop-in replacement for EN 590 diesel where the engine or machine carries the manufacturer's approval, and that a long list of manufacturers (Mercedes-Benz, Ford, Volvo and John Deere among those commonly cited) have issued such approvals for at least part of their range. Note that much of this information is published by fuel suppliers, who have an interest in it being read broadly.
What is not safe to assume is that approval is universal, or that it covers every engine a manufacturer has ever built, or that a vehicle old enough to predate the standard is included by default. Approval is issued per engine family, and the honest answer for any specific car is: check that manufacturer's own statement for that engine, not a general claim about the fuel.
Two further points, both undramatic and both real. Older fuel-system seals and hoses were developed against a different fuel, and paraffinic diesel's strong solvency can loosen deposits in a tank that has run on conventional diesel for years, which occasionally means a blocked filter shortly after switching, from dirt that was already there. And warranty terms follow approval, not chemistry: a fuel can be entirely harmless and still sit outside what a manufacturer has agreed to cover.
What this means at the pump
- Look for XTL, and treat it as a question rather than a synonym for diesel. The label exists precisely because this is a different fuel. If your vehicle is approved it is an easy choice; if you do not know, it is worth two minutes with the manual.
- Do not extrapolate from someone else's car. "My van runs fine on it" is evidence about that engine family. Approval is granted engine by engine.
- Expect marginally worse consumption, not worse performance. Lower density means less energy per litre. Higher cetane means better ignition. These pull in opposite directions and largely cancel in feel, but the litres tell the story.
- Do not assume it is cleaner in the local sense. The carbon case for HVO is about the fuel's origin and lifecycle, not about what leaves the exhaust pipe. It has no bearing on whether you may enter a low emission zone, which is decided by your vehicle's emission class.
- Remember the unlabelled route. If you burn ordinary diesel in Europe you may already be burning HVO as a blend component, entirely legitimately and with nothing to check. Only the neat fuel raises the approval question.
Why we cannot show you this on a map
It would be genuinely useful to know which forecourts sell HVO100 before setting out, and we would like to show it. The obstacle is the same one that runs through everything on this site.
Map data can record that a station sells a fuel type, and does so reasonably well for the long-established grades. HVO is newer, patchily tagged, and frequently sold from a single pump that appears or disappears with the supplier contract. A geographic database updated by volunteers is slower than a fuel that is still being rolled out, and there is no field anywhere for "the XTL pump was working on Tuesday".
So the useful signal, again, is a person: a driver who filled with it at that station, recently, and said so with a timestamp attached. For a fuel this new and this unevenly distributed, one recent report is worth more than any static entry, and where nobody has reported, the honest display is an empty space rather than a confident guess.