The new fuel war raging as F1's 2026 overhaul arrives

When Formula 1 revealed its roadmap for its all-new 2026 regulations, much of the discourse hinged on the performance-driven elements of the cars.

The introduction of active aerodynamics proved to be one of the main talking points, as did the near-50:50 split between the power generated through the internal combustion engine and the electric motor. It’s only natural that those aspects would court the most column inches given that the powertrain regulations had a knock-on effect on the aero rules, and the following grumbles of discontent from a range of team bosses kept the news flowing.

PLUS: The turmoil of F1's 2026 rules shift

However, there's another aspect that remains largely forgotten about behind the bigger-ticket items, which lies in the decision to pursue fully sustainable fuels for 2026. Although the automotive industry is throwing some of its weight behind the advancement of electric vehicles, aiming to extend battery performance and range, most manufacturers would prefer a way to extend the life of the internal combustion engine. If it can do so sustainably, it'll play a huge part in the worldwide transport networks, particularly in countries that do not have the requisite infrastructure or finance for electric vehicles.

F1 wants to be part of that, even with greater hybridisation, and thus has tasked the current range of fuel producers to concoct a formula that lives up to the sustainability demands. Although these fuels should be the same chemically, it's going to be a hotbed of advances.

What do the 2026 fuel regulations say?

Switch to fully sustainable fuel is among the many changes for 2026

Photo by: FIA

In short, all 2026 fuels must be produced in their entirety of “advanced sustainable” materials. The FIA defines this as “derived from a renewable feedstock of non-biological origin, municipal waste, or non-food biomass”.

The FIA will homologate the fuels and, with the cooperation of the teams and suppliers, will trace the materials used to ensure that they comply with the notion of sustainability.

For e-fuels, a synthetic fuel made from the reaction of hydrogen gas and carbon, the energy used for all elements of the production (the electrolysis of water for hydrogen and the cracking of carbon dioxide being the main consumers of energy), must be from either renewable sources entirely, or have been sourced to provide a reduction in greenhouse gas emissions versus the equivalent fossil fuels.

“There will be some independent checking about the exact source of the various components of the fuel, and there will have to be a certification for the fuels used to make sure they have a generally sustainable source”
Nikolas Tombazis

Biofuels must either be produced from second-generation feedstocks (i.e. non-food biomass that uses cellulose) or from first-generation biomass produced from food waste. This is to ensure that food crops are not ringfenced for biofuels, as this could affect the global food chain considerably.

Compared to the current fuels, the sustainable fuels in use for 2026 should be effectively chemically identical. The same limitations on composition apply, although this no longer needs to include a minimum of 10% ethanol as a ‘makeweight’ sustainable component – however, it is expected that 20% of the fuel will comprise bioethanol.

Everything is formulated to retain some degree of road relevance, with the theory being that the fuel used in F1 could be available on a garage forecourt to be pumped haphazardly into a thirsty SUV.

To ensure all fuels are up to standard and comply with the mandate to make them fully sustainable, FIA head of single-seaters Nikolas Tombazis says that there will be certification procedures applied and fuel samples taken to ensure they are equivalent to those presented for homologation. It’s effectively putting a spin on standard practice, but with the added validation of the sustainability credentials.

Tombazis says the composition of the fuels will be strictly monitored

Photo by: Mark Sutton

“There will be some independent checking about the exact source of the various components of the fuel, and there will have to be a certification for the fuels used by the fuel suppliers in order to make sure they have a generally sustainable source,” Tombazis explained. “As we currently do, we check the chemical composition that is used when we take fuel samples and make sure it is accurate in relation to the homologated fuel.”

How the new fuels will be developed

Both synthetic fuels and biofuels can be used in 2026, which is likely lead to blends of both so long as these fulfil the rules over composition. At their most basic, synthetic fuels are made through the combination of hydrogen and carbon monoxide through the Fischer-Tropsch process, while biofuels are made from myriad different steps. Ethanol fuels are produced from the fermentation of biological feedstocks, while hydrogenation - in the case of hydrotreated esters and fatty acids fuels (HEFA) - is generally used for sustainable aviation fuel (SAF).

And then you’ve got biofuel classifications: generation one being produced from food crops (HEFA using waste oils and fats to produce a fuel, ethanol fuels using sugars/starches), generation two using non-food crops like grass and industry waste, so long as the cellulose can be used to produce alcohols, and generation three coming from algae.

Professor Mohamed Pourkashanian, the head of Energy Institute at the University of Sheffield, explains that, although the technology exists to create the second and third generations, these are not yet large enough to produce fuels to a commercial level.

“At this moment in terms of SAF production the only, let’s say, mature technology is the first-generation biofuels that are available,” he says. “HEFA at the moment is the only one available for airlines to use. When we did Flight100 [Virgin Atlantic’s London to New York flight on 100% sustainable fuel], we used 100% HEFA.

“E-fuels - I can give you the example that in one meeting one person was receiving an award and it was 10 millilitres of e-fuel was given to him as an award, and they said, ‘well, you have the half of the world's reserve in your hand!’”

Although HEFA has become the biggest percentage of SAF, it likely won’t have a home in F1’s engines in 2026 unless it can be proven to be from waste feedstocks. And, given the environmental concerns to a) the global food chain and b) land use changes for fuel crops, the idea of producing e-fuels – or synthetic fuels – has become an increasingly important one.

HEFA fuels have a place in aviation but likely won't be powering F1 engines

Photo by: Erik Junius

It sounds almost like the production of snake oil: with air and water, you can make a fuel that is chemically identical to fossil fuels but without a lot of the nasty bits. Although it might sound too good to be true, there’s a lot of genuine progress in this sector.

“Both UK and EU mandates put a lot of importance on e-fuels, and for many reasons,” Pourkashanian adds. “First of all, energy security in addition to environment is important. And being dependent on the availability of the biomass is simply replacing some of the reliance on fossil fuel and therefore is not only extra cost, but it doesn't provide that energy security.

“Airlines want to replace the use of fossil fuel, because of the CO2 generated from fossil fuel. And, if you look at the carbon footprint of these two different types of SAF, if you compare HEFA, which only replaces around 70% of the fossil fuel when you use it, to e-fuel that replaces over 95%. And with the CO2 generated by fossil fuels, you see why e-fuel becomes very important.”

“We bring a Formula 1 mindset, which is allowing us to be very innovative and very fast in execution. We haven't had to take this fuel to a refinery, what we make in our plant is an already refinery grade fuel”
Paddy Lowe

E-fuels are produced through two inputs: the ‘green’ electrolysis of water for hydrogen, and the production of carbon monoxide from captured CO2. These are put into a Fischer-Tropsch reactor, in which the hydrocarbon chains are formed to produce a fuel and the ‘spare’ hydrogen ions react with the oxygen clipped from the carbon monoxide to form water.

And, like the developed biofuels, these are drop-in – meaning that they can be thrown into an internal combustion engine with negligible effects to its running.

Paddy Lowe, the former Williams and Mercedes F1 technical director, has entered the world of synthetic fuel production with his own company Zero Petroleum. Lowe says that the e-fuel development, rather than the biofuel development into the second- and third-generations, will be the bigger player as the sustainable fuel market expands.

“I believe this solution of synthetic fuels is fundamental to a large part of the energy transition, particularly around liquid fuels, which are essential for many, many transport sectors, not optional, best example being aviation,” says Lowe.

Lowe has founded Zero Petroleum, which is focused on the development of sustainable fuels

Photo by: Zero

“So it's about that passion to deliver it, we bring a Formula 1 mindset to that and an approach, which is allowing us to be very innovative and very fast in execution. And we have some unique chemistry actually to bring to the space. We haven't had to take this fuel to a refinery, what we make in our plant is an already refinery grade fuel.

“Biofuels are an interesting solution, but not one that will take us through in full to the energy transition, because there is a huge problem of scale up, because effectively they are agricultural products, they need farming to deliver the feedstocks.”

Will the new fuels have an effect on the cars?

Any consequences of the new fuels on the next-gen F1 cars will be twofold: firstly, whether the fully sustainable compositions yield any difference in engine power output, and secondly, how the fuel companies involved will elect to compose their liquid energy sources.

When the current E10 fuels were introduced in 2022, there were minor changes required to how the teams ran their powertrains to atone for the reduction in energy density. Mercedes’ engine chief Hywel Thomas revealed that development was necessary for some of the components too, which perhaps is an indicator of how 2026’s fuels may change the picture. Of course, there’s going to be new powertrains, but the architecture should remain largely the same.

PLUS: The key ingredients changing as F1's 2026 engine war shapes up

“We did have to do some development work of the engine, some mapping work, the usual things, just to match,” Thomas says. “I don't think the hardware was changed significantly from memory. I think there was a few alterations to some parts, but mostly it was more in the kind of way the engine ran.

“And, as you say, there's less energy content in the engine, so just a bit of a change to the overall performance of the PU. But it's certainly nothing like the amount of change that we've got coming with the '26 fuel.”

And then there’s the composition of the fuel itself. Thomas explains that, although both biofuels and e-fuels can be used as a blend, it might be down to the infrastructure that the fuel manufacturers have at their disposal.

Mercedes engine guru Thomas says minor changes were needed in 2022 when E10 fuel was introduced

Photo by: Carl Bingham / Motorsport Images

“The hydrocarbons comprising the fuel should themselves be identical to what we currently have, but the manufacturers will have different supply chains that may influence how they design their products,” he says. “And then there’s additives and other legal ways to enhance performance to ensure the fuels burn more cleanly and efficiently.

“I imagine what everyone's doing is looking at the make up of the fuel that they want, and then trying to work out what's the best way that they know of to get to those particular chemicals. If someone's got a route that's an e-fuel, and someone's got a route that's more of a biofuel, as long as it ends up with the same hydrocarbon structure, the engine probably won't mind.

“I imagine everyone will be basing it on what's their infrastructure and what can they make, but also people will be going out and buying parts from third parties so there could be some elements of the fuel that everyone will be using.”

“There is a 20% ethanol requirement. I strongly suspect that will just be serviced by bioethanol, which is very readily available, it's in all pump fuel”
Paddy Lowe

Although Zero has emerged as a partner of Sauber’s F1 team, it is not yet supplying product to the team – however, Lowe has cast a keen eye over the regulations. He echoes Thomas’ suggestion that most will opt for a blend, although says that producing second-generation biofuels will be the more difficult aspect of that.

“The rules allow full synthetic fuels, and they allow biofuels, but only second-generation biofuels,” Lowe says. “That's a much more difficult process, because in general, second-gen or waste bio will be cellulosic product, because if it's not cellulosic, you can eat it. Humans can't digest cellulose, this is the reason. So that is a much more difficult chemistry.

“So I think we'll see a mixture [of biofuels and synthetic fuels], but I have no way of knowing what the Formula 1 teams and fuel suppliers will be doing in terms of a mix between those two. There is a 20% ethanol requirement. I strongly suspect that will just be serviced by bioethanol, which is very readily available, it's in all pump fuel. And, ethanol is ethanol, it's not much doctoring you can do to it. So that will be the 20%, but the rest we'll see...”

Could it spell the end of hybrids?

When sustainable fuels were first touted as part of the F1 regulations, there were heavy suggestions among the fanbase that the championship could theoretically drop its hybrid components and revert to a naturally aspirated formula. Imagine it: a much-heralded return to V10 power, reminding all in attendance why ear plugs were once necessary as their eardrums burst among the first-lap chorus.

Lowe's Zero Petroleum brand is a partner to Sauber but as yet does not supply it with a product

Photo by: Andy Hone / Motorsport Images

When the current turbo-hybrids were first introduced, this was done to reduce overall fuel consumption with fuel-flow restrictions, and also champion the use of energy recovery systems to expand beyond the limitations of the original KERS package. Thanks to the energy recovery capabilities and the use of a turbocharger, efficiency of the current powertrains is well over 50%.

However, if F1 was able to achieve its net zero aspirations with a bigger internal combustion engine, it would offer a slightly different marketing message: if car manufacturers were able to invest in direct air carbon capture technologies to pull the same carbon emissions out of the atmosphere that they produce with the combustion process, then they could continue to invest in the ICE’s long-term future.

“It is a personal consideration of mine, not yet shared with the teams, even if we have spoken about it with the FIA, that if sustainable fuels work, we will need to carefully evaluate whether to continue with hybrid [technology] or whether better solutions will be available,” F1 CEO Stefano Domenicali said back in May.

This seems to be based on the supposition that most fans want more noise, although this has become a complaint that has dwindled significantly over the current regulations’ 10-year span. Some still yearn for the banshee’s shriek shed from a V10, or the ursine roar of a V12, but many race-goers find the current formula perfectly acceptable from a noise standpoint. You don’t need earplugs with the V6 turbo-hybrids, but you might want to bring them anyway.

“It's clear that passenger cars are going in that EV direction and I think there's a lot to be gained from it. The developments that we're doing will find their way into the road cars” Hywel Thomas

But, let’s be honest, a return to V8s or V10s is not very likely. F1 needed to retain hybrids to lure additional manufacturers into the championship, a strategy that courted Honda’s full return, the Red Bull-Ford partnership, and the addition of Audi to the ranks. And Thomas, on behalf of Mercedes’ High Performance Powertrains arm, encapsulates what the manufacturers want to get out of an F1 engine ruleset.

“Personally, I think if F1 wants to stay relevant to stakeholders, I think the hybrid nature of the power unit's really exciting,” says Thomas. “The development of the batteries is really exciting. It's all really relevant to what's happening on the road, so it’s a shop window for people to show what they can do. For that reason, I think we're heading in a sensible direction.

“I guess you could do something different if you wanted to, if the sport decided that was the way it wanted to go, OK, but I think the value to people like Mercedes it's clear that passenger cars are going in that EV direction and I think there's a lot to be gained from it. The developments that we're doing will find their way into the road cars.”

Sustainable fuels will have their part to play in shaping the next step of the F1 engine regs, but it’s going to depend on where we are as a society and what the automotive world wants. Loud V8s might be a great idea on paper but, if nobody wants to build them, even with fully sustainable fuels...

Adoption of sustainable fuels does not necessarily mean a return to the glorious soundtrack of V10s

Photo by: Motorsport Images