Formula 1 will limit energy density, octane level and energy flow when it moves to 100% sustainable and synthetic fuels in 2026 – as F1 chief technical officer Pat Symonds explains in the latest episode of The Race F1 Tech Show podcast.
The move to such fuels is part of F1’s intention to achieve the target of net-zero carbon emissions by 2030 and is part of the next-generation power unit regulations that will be finalised imminently and are expected to be signed off officially at the next meeting of the FIA world motorsport council in late September.
Symonds explained the rationale for such limitations is to ensure they are relevant to the road, given the intention is to create what’s called a ‘drop-in’ fuel that could be put into an existing petrol-powered road car, and to allow fuel competition that advances the science of synthetic fuels without the risk of one supplier and its team(s) gaining too big a performance advantage.
The intention is that these limits will still allow plenty of room for innovation among the fuel suppliers, given the regulations do allow freedom in how the fuel is designed beyond such limitations and the requirement to be 100% sustainable.
“From a competitive point of view, there are certain things we need to do in the regulations like putting a maximum octane content on it and things like that,” Symonds told The Race.
“But what we don’t want to do is to say how it should be done because to me that’s the competition. The give-back for motorsport is to develop these sorts of techniques and to see what the industry can do given a free hand.
“So our regulations will definitely say that everything must be sustainable. We will regulate a few things like the density within bands, like the maximum octane content.
“And one of the things we’re doing this a little bit differently is that at the moment, we regulate the power of the engines effectively by regulating the mass flow of fuel into them. The current Formula 1 engine has a mass flow limit of 100kg/h. You flow that fuel into the engine, then you add as much air as you need to burn it.
“If we kept that and we had perhaps some slightly different types of fuel – because the fuel at the moment is all very similar, whoever makes it – we may find that someone actually got quite a good power advantage from one rather than the other.
“So what we’re doing in 2026 is rather than regulating the mass flow, we’re regulating the energy flow. So much the same way when you get your gas bill at the end of the month or your electricity bill, you’re effectively paying for the kilowatt-hours that you’ve used.
“Similarly, we’ll be saying ‘this is how many kilowatt-hours – megajoules the engineering term – that you can flow in, in a given time.
“That we should get a very open competition as to how you produce the fuel. But we won’t get the possibility that someone may totally dominate the sport, because they have got a better fuel.
“We want to promote competition. But we also have to respect the fact that we want to go racing, and we like close racing.”
Given the synthetic nature of the fuels means that the fuel companies can produce their own hydrocarbon molecules, there is the potential for a step forward in terms of the energy density of the fuels.
Symonds explained that the regulations also need to be designed to prevent this to ensure that F1 avoids what he described as “rocket fuel”.
This has led to the regulation limiting energy density to a similar level to the current fuels used in F1, which are around the 43-44 megajoues per kilogramme range.
“We are putting a limit on energy density because we want to feel that is relevant to the road,” said Symonds when asked about the expected performance of the 2026 fuels
“We could go and make a rocket fuel. That’s not what we want to do. We want to try and advance the industry so that it is a genuine solution to future mobility, so the energy density will be similar.
“A lot of synthetic fuels are lower in energy density, and therefore in power, unless you flow an awful lot more through. Ethanol as an example, the alcohol fuels – ethanol, methanol, things like that, you do need to burn more of them to get the same power now.
“But that doesn’t mean that they don’t have a place because the advantage of those sorts of fuels is they’re actually quite cheap. And in our future fuel, we will have a reasonable amount of ethanol, probably anything up to 20%.
“But the performance of the total fuel will be quite similar to the fuel that we have now.”
For more on F1’s move to synthetic, fully-sustainable fuels, listen to the latest episode of The Race F1 Tech podcast.
The Race F1 Tech Show is brought to you by Aramco.