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Carnot Engines Redefining Heavy-Duty Power for a Decarbonized Future

The Challenge: How to replace the Diesel Engine?

At Carnot we are taking on the biggest challenge of our age; decarbonizing heavy-duty power and how to replace diesel engines. 

Hard-to-abate sectors — from shipping to long-haul road transport to remote power generation — face the biggest challenge in reaching net zero. Traditional internal combustion engine and especially diesel engines, waste much of their fuel energy as heat, and many cannot operate effectively on next-generation low-carbon fuels like hydrogen or ammonia.

Decarbonizing heavy-duty power requires technology that combines exceptional fuel efficiency with full fuel flexibility, without compromising on performance, reliability, or cost-effectiveness.

Carnot Engines – The World’s most efficient, multi-fuel engine

At Carnot Engines, we are developing the world’s most efficient engines. Conventional engines operate around 35% efficiency, where a Carnot Engine can operate at over 70% break thermal efficiency. By doubling fuel efficient, we half fuel consumption, delivering enormous cost savings to our customers.

A Carnot Engine can also work on any fuel, and switch anytime. A Carnot Engine can run on:

  • Hydrogen
  • Ammonia
  • Methanol
  • HVO/Biofuels
  • Biogas
  • LNG
  • Diesel

Our design targets >70% brake thermal efficiency — more than double the efficiency of many conventional diesel engines. By operating at higher temperatures and eliminating most cooling losses, Carnot Engines aim to dramatically reduce fuel consumption and slash greenhouse gas emissions across the toughest sectors.

Applications Across Multiple Sectors

Our technology is built for the hardest jobs in the most demanding environments:

  • Maritime power — main propulsion and auxiliary power units (APUs) for ships

  • Heavy-duty road transport — trucks, buses, and specialist vehicles

  • Off-grid and industrial power generation — remote mining, construction, and backup systems

These sectors demand high reliability, long service life, and global maintainability — our engines are being engineered to meet or exceed these benchmarks.

Driving Maritime Decarbonization

Shipping accounts for nearly 3% of global CO₂ emissions, and international regulations are tightening fast. Carnot Engines is working with leading shipping companies to demonstrate hydrogen and ammonia-fuelled engines in real-world maritime environments.

Upcoming trials include:

  • Hydrogen-powered auxiliary engine testing aboard a commercial vessel

  • Hydrogen Engines for Shipping with the UK’s first hydrogen auxiliary engine sea trials 

  • Ammonia-fuelled APU retrofit projects for improved efficiency and emissions reduction

  • Ammonia Marine Engines and Auxiliary power units 
  • Fuel-Flexible high efficiency engines
  • Decarbonised Port Power

Designed for the Net-Zero Transition

Our approach solves three critical barriers to decarbonizing heavy-duty power:

  1. Fuel flexibility — switch between low-carbon fuels as supply chains develop

  2. High efficiency — reduced fuel use means lower emissions and operating costs

  3. Modular scalability — from smaller APUs to MW-scale maritime powerplants

This combination allows operators to begin cutting emissions now while staying adaptable for future fuels and standards.

Carisbrooke Shipping is a family-owned British shipping company established more than 50 years ago. They have pioneered increasing vessel efficiency and reduced vessel emissions with a continued dedication to innovation and improving vessel design. We have had the great pleasure of working with Carisbrooke Shipping for several years including co-operating on a series of Clean Maritime Demonstration Competition grants, the UK Government’s flagship maritime decarbonising research grant. To date, we have won all three rounds of this competition together.

 

The Carisbrooke Team visit the Carnot Test site 

Our Partnership focuses on exploring how our technology can decarbonise the maritime industry. We are deploying the UK’s first hydrogen auxiliary power unit onboard a Carisbrooke Shipping Cargo Vessel and working closely together with Bureau Veritas and the Maritime and Coastguard Agency in delivering this project. By demonstrating how to deliver hydrogen auxiliary power for the marine industry, we can help to accelerate the decarbonising journey of the maritime industry globally and help the industry achieve the imminent IMO Decarbonising regulations.

Carisbrooke has also become Carnot’s primary Marine advisor, helping us focus our strategies and products for the Shipping Industry to maximise our product impact. They will also be our early customer for our first marine products.  

Carisbrooke has taken the leap from Partner to Customer and now to Investor and Advisor, demonstrating we have the technology to decarbonise the maritime industry. We look forward to working closely with Carisbrooke Shipping over the coming years and would like to thank them for their continued support.

Carnot & Carisbrooke Hydrogen Auxiliary Engine Project