A British engine manufacturing start-up is taking inspiration from a 200 year-old principle of thermodynamics to achieve a significant breakthrough in engine technology, one which promises a phenomenal 70%+ efficiency and zero emissions to boot. The Manufacturer’s James Devonshire sat down with Carnot Engine’s Head of Sales, George Hunter, to find out more…
Google ‘Carnot heat engine’ and the first result you’ll see is a Wikipedia entry explaining how a man by the name of Nicolas Léonard Sadi Carnot (Sadi Carnot) – a French military engineer and physicist – developed the most efficient heat engine that was theoretically possible in 1824.
Fast-forward to today and Londonbased Carnot Engines (Carnot) is bringing this engine technology into the 21st century, pioneering a massive breakthrough in performance while accelerating the adoption of decarbonised fuels.
As Carnot boldly states on its website: ‘Our objective is to have gigaton scale CO2e impact, decarbonising the most heavily polluting industries, and offer an engine technology which can become the biggest accelerant of reaching net zero.’
But could a technology developed exactly 200 years ago really hold the answer to advancing the world’s net zero ambitions? As you’ll discover, George certainly thinks so and his enthusiasm is rather contagious.
Current generation engines are fundamentally limited
Carnot was founded in 2019 by three pioneering engineers who wanted to solve the challenge of decarbonising large demand applications such as trucks, ships, generators and more.
As George pointed out: “Hydrogen fuel cells coupled with batteries are a brilliant combination for decarbonising light loads and shorter journeys. But when you get to the most heavily polluting industries and applications, you really need an engine because nothing else quite offers the same power density or high end range.”
However, according to George, the current generation of engines are fundamentally limited in that they only operate in the 25-35% efficiency range. And when you start exploring more sustainable fuels, like hydrogen and ammonia which are generally more expensive than fossil fuels, the economics of the exercise fall apart.
Inspiration from 200 year-old tech
Carnot’s innovation takes its inspiration from a 200 year-old principle of thermodynamics, known as the Carnot cycle.
The Carnot cycle is a theoretical thermodynamic cycle that represents the most efficient way to convert heat into work (or vice versa) using an idealised heat engine. The Carnot cycle is crucial in thermodynamics because it sets the upper limit on the efficiency any heat engine can achieve, based solely on the temperatures at which it operates.
While no real engine can achieve true Carnot efficiency due to factors such as friction, heat losses and material limitations, engineers can use the Carnot cycle to improve the performance of actual engines – and that’s exactly what the engineers at Carnot have done.
“Over the last five years, we’ve focused on dialling in our technology to get it to a point where it’s fit for purpose”, added George. “We’ve now proven that we can make an engine based on Carnot’s work, one that can handle the conditions we subject it to.”
George explained that Carnot has successfully taken engine efficiencies from 25-35% to 68-72%. “And, of course, if you double the efficiency, you halve fuel consumption. For companies spending hundreds of thousands on fuel each year, the cost savings can be realised pretty quickly.”
A fuel agnostic approach
As if doubling engine efficiency wasn’t enough, Carnot is also taking a completely fuel agnostic approach.
“We can run our engines on hydrogen, ammonia, methanol, biofuel, biogas, LNG, diesel, LPG and we can upgrade the engine to different fuels,” explained George.
“So, on one side you’ve got the massively increased efficiency, which saves money and lowers costs, and on the other there is a completely flexible fuel strategy,” he added.
With Carnot’s architecture, companies can be opportunistic in their approach to decarbonisation, switching between fuels as and when they need. “We can provide people with the right solution to meet their requirements.”
And with this fuel agnostic approach comes the real key to decarbonising engines. By running on hydrogen, ammonia or biogas, for example, companies can realise true zero emissions.
“There’s a perception that engines are inherently bad from a net zero point of view, but that is misguided. There is nothing fundamentally wrong with engines, it’s the fuels you use and how you use them that causes engines to produce emissions,” George said.
Attracting attention
Carnot’s combination of significantly improved efficiency and fuel flexibility has caught the attention of both investors and the government alike.
Indeed, the start-up has secured millions in UK government grants, including a £1.5m Energy Catalyst Grant and several injections of funding via the Department for Transport’s Clean Maritime Demonstration Competition.
Mitsui O.S.K. Lines (MOL), a Japanese transport company and one of the largest shipping organisations in the world, has also recognised Carnot’s potential. The Tokyo-headquartered conglomerate recently announced its intension to invest directly in Carnot, becoming the company’s latest shareholder and partner for the maritime industry.
As part of the collaboration, Carnot and MOL are co-developing a Maritime Auxiliary Power Unit (APU), optimised for the MOL fleet and aligned with its decarbonising strategy. As George outlined: “This includes using Carnot’s high-efficiency engine technology to reduce fuel consumption and emissions while utilising our fuel agnostic capabilities to adopt different decarbonised fuels including ammonia, methanol and LNG.”
A Carisbrooke Shipping vessel will be involved in a hydrogen auxiliary engine trial in January
Why the 200-year wait?
Perhaps the most obvious question surrounding Carnot’s technology is why hasn’t Sadi Carnot’s work already been developed by someone else?
According to George, there have been several attempts to create a heat engine with minimal energy losses, all of which ultimately failed because they were undertaken by existing OEMs.
“Back in the 1970s and 1980s, there were several attempts to make adiabatic engines”, added George, referring to a process in which no heat is transferred into or out of a system. “These effectively uncooled engines incorporated high temperature materials, like ceramics.”
But the problem with ceramics is that they behave very differently to metals. For example, while ceramics are brilliant at handling compressive loads and high temperatures, they aren’t so adept at handling cyclic loading with twisting motions. And when you consider that most engines are riddled with such movements, ceramics simply can’t stand up to the challenge.
The other sticking point for OEMs is that they have established manufacturing infrastructures which represent significant investments. Starting again from scratch to create what is necessary to build a brand new type of engine just isn’t feasible.
So, what some did was to use coatings and liners in place of ceramic materials. The issue with this was these materials behaved very differently to metals when subjected to high temperatures. The result is different materials shrinking and expanding at different rates, which inevitably leads to failures.
As George added, for OEMs, it’s not simply a case of taking tried and tested engine designs and adapting them. It instead requires a whole new approach and philosophy.
Another factor in all of this is that manufacturing technologies have also advanced enormously in recent years. Innovations like 3D printing are making it a lot easier and cost effective to make bespoke parts. Moreover, the ability of manufacturers today to work to micron level tolerances makes innovations like Carnot’s more achievable.
Carnot takes its name from Nicolas Léonard Sadi Carnot (Sadi Carnot) – a French military engineer and physicist – who developed the most efficient heat engine that was theoretically possible in 1824.
Carnot Engines out in the wild
So, when can we expect to see a Carnot Engine out in the wild? George said they have plans to deliver the UK’s first hydrogen auxiliary power unit sea trial in January.
As he explained, on most ships the main engines are responsible for propulsion while auxiliary engines provide electrical power for the ship’s various systems and equipment. The problem with these auxiliary engines (think of them as basically generators) is they tend to be diesel or petrol powered and have an oversized contribution to the vessel’s overall emissions profile.
Carnot and its partners Carisbrooke Shipping, Brunel University and the Manufacturing Technology Centre will be trialling a hydrogen engine for such an application in January. One of Carisbrooke Shipping’s K-Class cargo vessels will have a zero emission 50kW hydrogen auxiliary engine demonstrator mounted on its deck. The ship will then make trips back and forth between Bristol and Belfast to basically prove that the technology can be relied upon when needed.
It should also be mentioned that such a trial is no mean feat. George said that they’ve been working for some time with regulators, ports and His Majesty’s Coastguard to lay out how such fuels can be used in a maritime context.
In addition to this trial, Carnot is also embarking on a biogas project in Indonesia which will use gases generated from agricultural waste to power a mini-grid setup. With another biogas project in the Netherlands and a hydrogen project in Korea, 2025 will be the year in which Carnot proves its technology in real world situations.
Addressing the manufacturing skills shortage
Like many manufacturers today, Carnot isn’t immune to the ongoing skills shortage impacting the manufacturing industry. To address the situation, the company has developed its own apprenticeship programme and is reaping rewards as a result.
But as George highlighted, Carnot’s recruitment challenges aren’t focused at the top end of their business, but rather the mid-level.
“At the senior level, we’ve managed well by tapping into a network of seasoned professionals from the Formula 1 industry, where several of our people hail from”, he said. “These are people with 20 to 30 years of experience who have built and designed engines throughout their careers. And many were looking for a change – whether that’s a new challenge or simply a better work-life balance – and our connections within F1 have made this recruitment at the top end relatively straightforward.”
However, filling roles at the mid-level has been a much bigger challenge for Carnot. The pool of candidates with the right combination of skills and experience it needs is practically “non-existent”, according to George.
To address this gap, the company has leaned heavily on apprenticeships. Their approach involves bringing in young talent directly from college. “They spend one day a week in school and four days a week with us,” said George, “gaining hands-on experience in the workshop.” This longterm investment in apprenticeships allows Carnot to build and mould the talent it needs from the ground up.
While it’s a slow process, taking years to fully develop these individuals, George said it is proving to be an effective strategy. “These young recruits are passionate about working with their hands rather than sitting behind a desk – they want to be involved with engines and tools. Creating an exciting and engaging environment has also helped us retain these apprentices.”
In the long-term, George believes the entire industry needs to focus more on apprenticeship programmes as a solution to the skills gap. While it’s a long-term commitment, with the right vision and environment, it “can build a sustainable talent pipeline for the future.”
Discover more about Carnot Engines at carnotengines.com
Key takeaways:
- Carnot Engines is a London-based start-up that takes its inspiration from a 200 year-old principle of thermodynamics
- Carnot’s engine architecture boasts significantly improved efficiency vs. traditional engines and is fuel agnostic
- Carnot has secured millions in UK government grants and investment from big shipping players
- Carnot has proactively addressed the ongoing skills shortage by developing its own apprenticeship programme
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