Darlington campus now a centre of excellence for future engines

For Cummins, Darlington is now a centre of excellence for future engines, including hydrogen internal combustion engines, with local teams having completed a government‑backed project to create the ‘DNA and architecture’ of a truck‑sized hydrogen engine just waiting for full production. The work has delivered a medium‑duty engine architecture that can be scaled to heavy trucks and off‑highway machines, positioning the town as one of the UK’s most important hydrogen R&D hubs.

From his on‑highway product planning role, Miles Askew sees that achievement in the context of a fast‑moving market and an evolving regulatory landscape

‘Darlington has really been the centre of excellence for the hydrogen engine work and we went through this 18 to 24‑month government‑funded project with a consortium of businesses where the whole aim was to figure out what the genuinely novel technologies were for a hydrogen engine, how we put the building blocks together and how we take what we know from diesel and create a new kind of product that still feels familiar to operators.

‘At the end of that process we came out with the engine DNA and the architecture; we can show you how the system works, where the pipes run, how it integrates into a truck, but we haven’t productionised it yet because legislation and market demand aren’t quite in the place they need to be for a commercial launch.

‘There’s a strange tension at the moment where regulation doesn’t yet match what the market is pulling for and where the technology is capable of going, so you have this divergence around what the ‘right’ product is. ‘From an engineering point of view, a hydrogen engine looks like a really straightforward way to decarbonise transport – there’s no carbon in the fuel, so you’re starting with a zero‑carbon energy carrier – but today the cost of hydrogen and the level of infrastructure you’d need mean it doesn’t yet stack up in a way that fleet operators are ready to jump on; so the technology is sitting there, proven on the dynos here in Darlington, waiting for the policy landscape and the economics to catch up.’

Miles is clear that the broader Teesside build‑out – from hydrogen linked to carbon capture to other emerging projects – could transform the region’s fuel map, but he is pragmatic about where that first wave of molecules is most likely to go.

‘Hydrogen absolutely has a role to play in decarbonisation, and if you look around Teesside and the wider North East there are some very big industrial processes where it feels like a no‑brainer.

‘You think about steelmaking, about concrete and cement plants, about all the places where we burn huge amounts of natural gas, and hydrogen can often be a drop‑in that lets you decarbonise those really intense processes without ripping everything up and starting again.

‘The interesting question then becomes: when we’ve got a lot of hydrogen flowing in the pipeline, who gets priority and who’s prepared to push the most for it?

‘My instinct is that the automotive sector – trucks and buses – may not be at the top of that list compared with big fixed industrial users, so even if we as an industry create a lot of hydrogen and we as Cummins can stand up a product that clearly works, we still need to see whether the market will actually go for it, and we’re very much in that watching brief at the moment to see how it pans out and when the tipping points arrive.’

That realistic tone sits alongside a clear sense of pride in what has already been achieved on Yarm Road.

‘When you strip the jargon away, what the team here have done is design and build a truck‑sized engine that runs on hydrogen, not some tiny lab prototype, and that’s quite an astonishing thing for a plant in the North East of England to be able to say,’ he adds. ‘You start with a blank sheet of paper, you ask what the architecture needs to look like, what you do with fuel storage and air management and combustion, and then you’re lucky enough, as we are in Darlington, to have a springboard in the form of a world‑class engine engineering team who can take that concept and turn it into hardware you can fire up in a test cell.’

One of the striking points in this account is that, for all the attention hydrogen attracts, Cummins’ green strategy in Darlington is deliberately broader than any single fuel. The local engineering group has been working on a new ‘fuel‑agnostic’ engine approach where core components can be configured to run on advanced diesel, gas, hydrogen and renewable fuels such as HVO (Hydrotreated Vegetable Oil), allowing fleets to decarbonise at different speeds.

Miles tells me: ‘Legislation always drives innovation, it always drives changes in product, and here in Darlington we’ve been developing a new generation of engines to meet the next big emissions step (Euro 7) in 2029.

‘When we were doing that, the original programme wasn’t about hydrogen at all, but we realised a lot of the building blocks – the base hardware, the combustion architecture, the control systems – could be used in different combinations, so we created this fuel‑agnostic principle where we can pick and choose the right parts and construct an engine that’s optimised for diesel, or gas, or HVO, or hydrogen, without having to design four completely separate platforms from scratch.

‘As I said at the recent BUSINESSiQ event with Ben Houchen, this isn’t all about hydrogen, because if you look at our new engine technology we’re making sure it can use sustainable fuels like HVO, where you’re taking waste products and turning them into a low‑carbon fuel that can go into a modern engine.

‘Those fuels are in the market today, they plug into existing refuelling infrastructure, and if we make sure our products can run on them robustly, we can drive significant carbon reductions across the fleet while hydrogen economics and infrastructure mature in the background.’

While hydrogen engines and fuel‑agnostic platforms grab the technical headlines, an equally important part of Cummins’ green story in Darlington is what is happening inside the campus away from the test cells. As environmental project manager, Jaime Mullis is responsible for the campus‑wide projects that help deliver the company’s 2030 and 2050 sustainability targets – from permits and pollution control through to energy, water and waste reduction.

‘My role is very much about the environmental projects that happen within the site boundary, so rather than focusing on the product that leaves the gate, I’m looking at everything inside it that interacts with the environment and making sure it supports our 2030 goals and 2050 aspirations as part of Cummins Destination Zero Strategy,’ he explains.

‘That ranges from managing the campus environmental aspects and impacts, permits and overseeing the site’s environmental performance, to regulating air emissions from key processes such as painting. We also lead initiatives that reduce energy use, cut waste, and generally make the Darlington site as green and efficient as we can make it.

‘Anything that’s funded through that corporate environmental pot, I look after as a project, and we’ve got some big schemes bubbling away in the background that will really help us get over the line on our targets.

‘We’re on track overall, and we’ve already implemented some projects that have absolutely smashed the interim goals we set ourselves, which gives you confidence that if you keep backing the right ideas, you can move a big industrial site like this a long way, quite quickly.’

One of Mullis’ flagship successes is the switch from solvent‑based to water‑based paint across the engine lines, a project that was completed in late 2024 and audited by the council in early 2026. ‘We installed the new water‑based paint system in the fourth quarter of 2024 and it’s been running for about a year now, so we’ve just been through an environmental permit audit with the council and the data from that is really encouraging.

‘What it’s telling us is that we’ve achieved around an 80 per cent reduction in VOC emissions from that process, which means we have already exceeded our 2030 target – that was set at a 50 per cent reduction – by a very comfortable margin simply by implementing this project.

‘We’ve essentially removed solvent‑based paint from all of the engines we produce here, with the exception of marine engines which run through a separate process, so it’s not a small pilot, it’s right at the heart of what we do.

‘When you hit a 50 per cent reduction target six years early and actually deliver more like 80 per cent, it shows that the combination of corporate backing and local engineering know‑how can deliver really big environmental gains without compromising the output that keeps people in jobs.’

‘Alongside air‑emission projects, water has been a major focus, with the campus already running a substantial rainwater harvesting system and looking to expand capacity.

‘We’ve had a 50,000‑litre rainwater harvesting tank out at the front of the site for a number of years now and that feeds all of our shop‑floor welfare toilet facilities, so you’re talking about a really significant reduction in potable water use just from that one system,’ Jaime explains.

‘We’ve now secured additional funding to increase the capacity and add separate rainwater systems because, frankly, we get a lot of rain in Darlington and it feels like a waste if we’re not capturing and using as much of it as we sensibly can.’

The principle is simple but powerful.

‘On the engine plant side we’re using harvested rainwater where most of our water usage actually is, and we know that other parts of Cummins have put in even larger systems that feed things like cooling‑tower top‑ups, so there’s a lot of learning being shared.

‘It might not sound glamorous, but when you combine big tanks, smart controls and the good old North East climate, you can make a dent in both your water footprint and your operating costs, and that’s exactly the sort of win‑win that keeps people engaged in the environmental conversation.’

For him, the green transformation of the Darlington site clearly goes beyond individual projects and into the bricks‑and‑mortar of the campus itself.

‘Within the boundary of the plant, what I can control is how green we are as an operation, so we’re looking at everything from the structure of the buildings and how we upgrade them, through to getting gas out of processes where it’s no longer needed and reducing the amount of waste that flows through the test facilities.

‘We’re working on the fabric of the offices to control heat loss, on systems that let us recycle the oil and coolant we put into engines, and on keeping as much as possible in‑house so we’re not constantly buying fresh materials we don’t really need to be consuming.

‘It doesn’t feel like a compliance exercise where we tick a box and move on; it’s very much about building a sustainable way of operating that makes sense to the people who work here.

‘Sometimes when you talk about the environmental side people can switch off, but if you can say we’ve saved this much money because we’re buying less energy, less fresh oil, less coolant, and by the way we’ve also reduced our emissions and our waste, suddenly you’ve flipped the conversation and everyone sees that being greener and being more efficient are the same thing.’

Behind the technology and the infrastructure is a workforce that increasingly sees Darlington as a place to build a career in the new energy economy, and Miles says the buzz is tangible.

‘Cummins is full of good people; we just seem to employ great people, and that’s not just a line,’ he says.

‘BUSINESSiQ has already spoken to colleagues from the allotments and from other parts of the business, and there is a genuine ethos here about breaking boundaries, being quick enough to keep pace with the market and constantly pushing for new technology, whether that’s in the product or in how we run the campus.’

Jaime, who admits he used to drive past the site without any real idea what happened behind the gates, says the scale of investment was a revelation.

‘I’ve been here about four and a half years and before I joined I’d gone past this place hundreds of times without understanding what was going on.

‘When someone mentioned the job, my first reaction was “diesel engines” and I didn’t really know what that meant in practice, but once you walk around and see the R&D, the test facilities, the new Powertrain Test Facility and the money going into environmental projects, you realise it’s a really good place to work where they’re always pushing for the next bit of technology and the next set of environmental targets, and that constant push to lower and then lower them again is actually very motivating.

‘From the product side we’re always taking on apprentices and graduates, and we’ve got a steady flow of students coming through the organisation, so the skills pool is there,” he tells me.

‘Because hydrogen and new power are relatively novel, we’ve seen people move across from engines into new technologies and then sometimes transfer back again, bringing that knowledge with them.

‘It’s worth stressing that hydrogen isn’t the only decarbonisation lever we’re pulling, especially because the economics and market pull aren’t quite there yet and the government has been pretty clear that it doesn’t see hydrogen as the main solution for decarbonising trucks in our region.

‘The EU takes a different view and says hydrogen’s zero‑carbon status counts in its favour, but UK policy doesn’t line up with that, and if you tie that back to my role in product planning and strategy, we have a team here in Darlington trying to make global decisions in a world where regulation is diverging and sometimes not very firm. What’s good for vehicle operators isn’t always aligned to the pressure on vehicle manufacturers is another dynamic here.

‘The upside for the North East is that we’ve got not just product development but global product strategy being done here in Darlington, so the region has a real voice in those conversations.’

Walk around the site today and it is clear that Cummins Darlington was never just an engine plant; it is a green‑energy campus where hydrogen prototypes and Euro 7‑ready diesels share space with rainwater tanks and water‑based paint lines, all underpinned by a skills pipeline that ties the town into the wider Tees Valley clean‑energy story.

The key is to keep moving.