The promise of hydrogen technologies

How hydrogen can fuel a more sustainable transport system

Hydrogen technologies
Credit: Pixabay


In my August article on the rise of green motorsport, I briefly talked about alternative cleantech and fuels. In this article, I focus on HICE,  comparing it to hydrogen fuel cells, which we covered in a previous article (linked below). Later, I will delve into renewable fuels.

Hydrogen internal combustion engine (HICE)

An internal combustion engine fueled by hydrogen presents a unique and promising solution in the pursuit of cleaner and more sustainable transportation technologies. One of its primary advantages lies in the fact that the combustion of hydrogen generates significantly fewer carbon-based pollutants compared to traditional gasoline or diesel engines. Hydrogen combustion yields only water vapour. However, it has certain limitations that can hinder its path to achieving zero emissions:

Handling and storage

Hydrogen, as a gas, is highly flammable and requires special handling and storage procedures to ensure safety. Its lightweight and highly diffusive nature can lead to challenges in containment, especially in a vehicle’s fuel system. Ensuring the safe transport and storage of hydrogen is a key consideration in the widespread adoption of HICEs.

NOx emissions

Although hydrogen combustion is cleaner than petrol or diesel in terms of carbon emissions, it can produce nitrogen oxides (NOx) during combustion. This occurs because the combustion takes place in an atmosphere containing nitrogen and oxygen, and the high combustion temperatures in the engine can lead to NOx formation.

NOx is a pollutant that contributes to smog and can have adverse effects on air quality and human health. To achieve true zero emissions, HICEs need to address and minimise NOx emissions through advanced combustion control and exhaust after-treatment technologies.

Energy efficiency

Hydrogen has a lower energy density compared to conventional fuels like petrol or diesel. As a result, more hydrogen needs to be consumed to produce the same amount of power. This can impact the overall energy efficiency of the engine and may necessitate larger engines or the use of turbochargers and superchargers to compensate for the lower energy density.


Several businesses have made significant advancements in hydrogen technologies for road transport. A notable example is Dumarey Hydrocells, a brand of the Dumarey Group, based in Turin (Italy). Previously known as PUNCH Hydrocells, they cover the entire value chain of the hydrogen ecosystem: production, storage & distribution, fuel cells and HICEs.

Originally, it was part of Fiat-GM Powertrain (an alliance between Fiat and GM). In 2005, Fiat left and became GM Powertrain Europe Turin, a centre for diesel engines and related electronic control development of GM globally. In 2020, GM sold it to the PUNCH Group (now the Dumarey Group), becoming PUNCH Torino, with the mission of developing innovative propulsion and control systems.

The Dumarey Group is a Belgian company developing propulsion systems for hybrid and electric vehicles. In January 2023, The European Investment Bank (EIB) and PUNCH announced a financing agreement of €40 million for hydrogen propulsion technologies. The Dumarey Hydrocells team in Turin will receive the majority of the investments.

(I met them last year at a mobility technology event in Turin, where Fiat was founded in 1899. Fiat, formerly part of FCA, is now a subsidiary of Stellantis. I worked for Fiat in the ’90s.)

HICE vs hydrogen fuel cells

HICE and hydrogen fuel cells are two distinct technologies that utilise hydrogen as a fuel source to power vehicles and machinery. Let’s compare HICE and fuel cells in several key aspects:

Aspect HICE Fuel cells

Operating principle

HICEs operate on the same basic principles as traditional internal combustion engines, such as petrol or diesel engines. They combust hydrogen with air to produce mechanical power. They are characterised by the familiar “burn and explode” process found in traditional engines Hydrogen fuel cells generate electricity through an electrochemical process. Hydrogen is split into protons and electrons, and as protons pass through a membrane, electricity is produced. This electricity is then used to power electric motors that drive the vehicle


While HICEs produce fewer carbon-based pollutants than conventional engines, they can still emit nitrogen oxides (NOx) and have some greenhouse gas emissions associated with the production and transportation of hydrogen Fuel cells are renowned for being nearly emission-free. The only byproduct of the hydrogen fuel cell process is water vapour, making them a truly zero-emission technology


HICEs tend to have lower overall efficiency compared to fuel cells. This is because of the inherent limitations of the internal combustion process, including heat losses and incomplete combustion Fuel cells are more efficient in converting the chemical energy in hydrogen to electricity, which is then used to power the vehicle


HICEs can be simpler in design and easier to retrofit into existing vehicle platforms. They may not require a significant departure from traditional petrol or diesel engines Fuel cell systems can be more complex and require a separate electric motor or powertrain system to drive the vehicle. The entire vehicle needs to be re-designed


Hydrogen fueling infrastructure for HICEs is a lot less developed compared to petrol or electric charging infrastructure Fuel cells require dedicated hydrogen refuelling stations. There are only a few stations at present but are growing in number


HICEs have found applications in certain heavy-duty vehicles like trucks and buses, where combustion engines offer advantages difficult to replicate Fuel cells are more commonly used in passenger vehicles and other applications where zero emissions and high energy efficiency are a priority

Both HICE and hydrogen fuel cells have their unique advantages and challenges. For more on hydrogen fuel cells see my article: Fuel Cells: a reason why Elon Musk may be wrong.

Hydrogen technologies for rail, aviation and shipping

Hydrogen technologies have emerged as promising solutions to decarbonise the rail, aviation and shipping industries too. Some companies have made advancements in hydrogen technologies for these industries. Notable examples include:

  • Coradia iLint – the world’s first commercial hydrogen-powered train, currently in operation in Germany and Austria
  • ZeroAvia’s hydrogen-powered aircraft for 19 passengers, expected to enter service by 2024(5)
  • Ballard Power Systems’ pioneering work on hydrogen fuel cells for ships

Disclosure: I am an investor in Ballard Power Systems, which also develops solutions for automotive businesses. (I started to learn about fuel cells in the late 90s working for Ford in the US.)

Final thoughts

HICEs are simpler in design and can be more readily adapted to existing vehicles, but they do not achieve the same level of emissions reduction and energy efficiency as fuel cells. Hydrogen fuel cells are highly efficient and nearly emissions-free but come with infrastructure challenges and complexities in integration. The choice between these technologies often depends on the specific application and the environmental goals of the project.

Both technologies have the potential to play important roles in reducing greenhouse gas emissions in the transportation sector. Especially for larger vehicles. HICE more in the short and medium term, fuel cells in the long term.


P27 is a member of the Coalition for the Decarbonisation of Road Transport (CDRT), established by the Green Finance Institute and supported by the UK Treasury. The scope of the CDRT includes hydrogen technologies, explored as part of potential solutions for heavy goods vehicles (HGVs). Below you can find the coalition’s activities (we provided assistance on some):

CDRT projects and reports

To learn how we can help your business explore or invest in these new technologies:

Business services


Mauro Tortone

View posts by Mauro Tortone
Mauro advises financial services, technology and mobility businesses and leads the Strategy & Finance practice. His expertise is in strategic change, capital markets and more. Mauro has over 25 years of experience working with banks such as UBS and Deutsche Bank, smaller financials, fintechs and others across Europe, the US and Asia. He sat on the CISI Corporate Finance Forum Committee for ten years and is passionate about sustainability.
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