Which sustainable fuel is cheapest for your fleet?
The cheapest sustainable fuel isn't the one with the lowest pump price: drop-in HVO often beats B100 once real total cost of ownership is counted.
The pump price: what you actually see
If you only compare the price tag, the ranking looks simple. B100 usually shows the lowest per-litre price, followed by HVO, then fossil diesel, whose price still swings with oil markets. On this criterion alone, B100 looks like the obvious pick for cutting the fuel bill.
That single figure is exactly what pushes many buyers to decide too quickly. The per-litre price only tells part of the story: it says nothing about actual vehicle consumption, engine wear, or the ancillary costs of running that fuel over time. Yet it is the total operating cost that ultimately shapes your fleet budget.
The cheapest fuel per litre is not necessarily the cheapest fuel to actually run.
TCO tips the comparison in favour of HVO
Consumption and engine efficiency
HVO has a higher cetane number than fossil diesel and B100, which improves combustion quality. In practice, this translates to reduced fuel consumption, in the range of 2 to 5 percent depending on fleet profiles and operating conditions. Over large annual volumes, this difference in fuel efficiency has a greater impact on the final bill than the few cents difference shown at the pump.
Engine compatibility: the real tipping point
This is where the ranking flips. HVO is a drop-in fuel: it can replace fossil diesel without requiring engine modifications, changes to storage infrastructure, or a waiver of the manufacturer’s warranty. B100, on the other hand, often requires adjustments to seals, filters, and sometimes engine calibration, along with explicit approval from the manufacturer to ensure the warranty remains valid.
This difference comes at a direct cost: additional technical inspections, more frequent maintenance, management of residues resulting from less complete combustion, and the risk of vehicle downtime during the adaptation phases. Combined with the difference in fuel consumption, these costs can offset—or even reverse—the initial price advantage of B100 over HVO.
The hidden costs the sticker price never shows
Beyond consumption and maintenance, several cost items stay invisible at the point of purchase but weigh heavily over time. They cover both fuel availability and its future tax treatment.
- Adaptation CapEx: seals, filters, engine calibration and OEM sign-off required for B100.
- Vehicle downtime during inspection or conversion phases.
- Uneven B100 availability depending on production regions and seasons.
- Fossil diesel exposed to carbon taxation likely to tighten in coming years.
- Multi-supplier sourcing costs needed to secure volumes.
- Risk of voided OEM warranty if B100 usage guidelines are not respected.
Taken individually, each item looks marginal. Added up across a fleet of dozens of vehicles over several years, they can outweigh the initial price gap between B100 and HVO.
Modelling your real cost with your own fleet data
The only reliable calculation starts from your own numbers: annual mileage, average consumption per vehicle type, current maintenance frequency, and fuel volumes ordered. Cross-referencing this data with suppliers' actual prices makes it possible to estimate a cost per kilometre rather than a cost per litre — the only comparison basis that actually matters between B100, HVO and fossil diesel.
The cheapest sustainable fuel for your fleet depends on your vehicles, your mileage and your operating constraints: there is no universal answer that fits every fleet. HVO's advantage comes from its ease of use, and B100 can still make sense for certain profiles once adaptation costs are absorbed, but only a fleet-specific, numbers-based comparison lets you decide with confidence.
Start a Heeding Flash Audit to get a quantified estimate of the TCO best suited to your fleet.
Compare objectively before choosing your fuel
That is exactly what a digital platform like Heeding enables: bringing together offers from several sustainable fuel producers and distributors, comparing real-world prices, and placing orders without endless phone calls or email chains. Buyers who compare their options this way, instead of renewing a contract out of habit, save an average of €4,000 per order.
