What's it like running a car on sustainable fuel?

Sam's MX-5 takes its first sip of Coryton's Sustain with surprising effects. Is this really the future?

By Sam Sheehan / Thursday, 26 February 2026 / Loading comments

Is 2026 the year the world finally starts to take sustainable fuels seriously? Formula 1 is certainly helping, because while teams have spent the last few weeks grappling with overly complicated hybrid systems, it’s probably a good sign that there’s been no mention of significant engine issues with this year’s net-zero fuels. Managing battery power in this new technical era is very challenging. Running the world’s most complicated racing engines on 100 per cent sustainable fuel, not so much.

This is nothing new outside of F1 of course, as evidenced by the fact Coryton’s own sustainable petrol and diesel alternatives have been produced from its Essex refinery for over a decade. And now, barely two weeks before the lights go out in Melbourne, I’ve had my first go in a road car - my car, in fact - using the stuff. Since my NC Mazda MX-5 is already on its second engine (I’m not sure the previous owner had ever heard of ‘servicing’), and is currently my main source of transport, I’ve been a little apprehensive. But now, after a week of running on Sustain, I have some interesting findings to report. Not all of them good.

Before I reveal what life on the new juice is like, let’s run through the basics of what sustainable fuel actually is, why it’s got masses of potential, and why adoption so far has been pretty slow. Coryton’s Sustain fuel is effectively a biofuel, but it’s not made from growing specific crops (which would mean it competes with agricultural land that could otherwise be used for food farming). Instead, it uses farming and organic waste - essentially crop by-products - and also food waste that’s not fit for human consumption. It therefore utilises waste products already in existence, so while it’s not technically net zero, it’s also not having a notable impact on the environment.

This means the initial phase of development is different to F1’s net zero fuel, which uses a mix of non-food waste (including wood waste), household waste and carbon capture technology, yet the result is the same. Both fuel types seek to reduce or completely eliminate the use of fossil fuels to produce a material that’s treated with enzymes, fermented into ethanol and then, using chemistry to mix the constituent molecules, converted into a sustainable, ultra-low ethanol petrol equivalent. Sustain’s fuel products are rated at 98 RON and above, with racing-grade stuff produced for motorsport reaching 102 RON, like F1 fuel.

Being shown around the Coryton refinery site in Essex, it’s clear how the final mixing process is, to the untrained eye at least, basically the same as regular fossil fuels. In fact, the site where Coryton’s giant mixing tanks are located, close to Southend-on-Sea in Fast Ford territory, is largely still a conventional oil refinery, with only a small area of the facility dedicated to Sustain production. Of the eight to nine million litres of fuel produced here a year, just 100,000 litres are for Sustain, although that’s due to demand - not capacity limitations.

That demand has been steadily increasing in recent years, with everything from mid- and lower-rank motorsport categories to OEMs like JLR and Mazda (including Mazda’s heritage fleet) - as well as plane manufacturer Airbus - requesting Coryton’s services. To achieve this quickly and flexibly, the firm has a lab on site, which from the outside looks like one of those temporary office buildings you’d find on a construction site but from the inside is very much a cutting-edge chemistry research department. In there, lab-coated scientists work with high-tech machinery (can you tell I’m a science noob?) used to test and develop new mixtures, sometimes as soon as the request comes in. It’s just an engine-on-a-dyno away from being a fully in-house setup - and is clearly a lesser-known example of a small-scale British operation indulging in global innovation.

Not everything produced here is 100 per cent sustainable fuel, because some products use a mix of fossil and Sustain to suit different applications. But perhaps most excitingly for us lot, most cars - including classic ones - can take high, if not full, percentages of sustainable fuel. In fact, the fuels don’t just behave like fossil fuel, they typically contain less than one per cent ethanol, which is a fifth of what higher-octane E5 fuel contains at the pumps. This means they’re actually preferable for classic car owners.

Racing teams like them too, even if they’re not mandated to use them, because, surprise-surprise, lab-developed fuels are cleaner than fossil-derived ones. This means more consistent performance, which in a competitive setting is vital. It’s also easier for motorsport teams to, in the name of performance, swallow the biggest challenge facing sustainable fuel: the price.

You’ll need to spend about £5.50 per litre to fill your car up with Sustain’s RON 102 fuel, which is comparable with equivalent racing fuels. But even the lower-grade mixtures intended for road cars are going to be comfortably more than double the price of at-the-pump petrol. Hardly surprising given the current scale of production, but clearly that is a negative aspect when it comes to encouraging fuel stations to feature a Sustain pump on their forecourts, let alone luring even the most curious of motorists to switch to the stuff. The hope, of course, is that this will improve with further development, meaning it’s not impossible to imagine a time when Sustain fuel will feel more like a higher-octane fuel, in price terms, than something completely incomparable.

Is it actually worth it though? That’s where my MX-5’s tank of Sustain 98 RON Classic Super 80 comes in, with its 80:20 Sustain to fossil fuel mix making it slightly cheaper at £4.65 per litre. That means my 50-litre tank costs £232.50 to brim, which is three and a bit times more than the £75 I’d presently be paying to receive the same volume of high-octane at a petrol station. It’s obviously enormously expensive. But for those who can afford it, there are noticeable differences to fossil fuel petrol.

Firstly, the smell. That familiar cold start petrol smell we’ll all recognise is swapped for a floral scent, which feels appropriate given that the fuel is made using waste that includes plants - even if it’s actually got nothing to do with that. Then there’s the throttle response. It feels like the jump you’d experience if you swapped normal for high-octane petrol, then took the car for a blast on one of those cool summer evenings, when the air is at its densest. It’s clearly still the same NC 2.0-litre under the bonnet - it’s not like getting a remap where torque curves change and rev limits are raised - but the engine seems noticeably keener at all revs.

I think it might be running more efficiently too, although I need to empty the tank before I can do the maths and confirm that it’s not just because the Mazda was properly brimmed. I’ll report back on that in a future fleet update on the car. Either way, I do feel a bit smug driving the MX-5 right now, knowing I’m contributing significantly less CO2 into the atmosphere, and also pumping less toxic stuff out of the exhaust pipes too. It’s British-made as well, and not far from where I live.

First impressions, then, are good: performance improvements and sustainably sourced - win-win. Alright, yes, even the cheapest stuff is going to be more than twice the price of petrol per litre. But that’ll improve with economies of scale. EVs obviously have a significant role in the present and future, but this gives me real hope that we can still drive our ICE cars for many more years, while reducing our reliance on fossil fuels.

F1 will no doubt help ramp up awareness (albeit not as much as if cars switched to sustainable fuel V10s!), but what the team at Coryton arguably needs now is more government and regulatory involvement to make this stuff cheaper to produce for motorists. Then, just maybe, we’ll get to keep our engines forever.