· 12 min read
The global transition to a low-carbon economy requires the large-scale deployment of clean energy technologies, fundamentally reshaping value chains and stakeholder dynamics. Among these technologies, hydrogen—long integral to the energy and chemical industries—is emerging as a key enabler of deep decarbonisation. Clean hydrogen offers a viable solution for reducing emissions in hard-to-abate sectors such as steel, cement, aviation, shipping, rail, and long-haul road transport, where electrification remains technically or economically challenging.
However, unlocking hydrogen’s full potential requires more than recognising its environmental promise. It calls for a coordinated redefinition of roles across the public and private sectors and aligning industrial strategies around a shared vision. Success hinges on a comprehensive approach integrating economic viability, supportive policies, technological innovation, and robust safety standards.
Transportation is the second-largest producer of global carbon dioxide (CO2) emissions, after electricity and heat generation (see Figure 1), and one of the most challenging sectors to decarbonise due to its distributed nature and the advantages provided by fossil fuels in terms of high energy densities, ease of transportation, and storage. Greenhouse gas emissions from transportation primarily come from burning fossil fuels in cars, trucks, ships, trains, and planes. Globally, over 94% of transportation fuels (gasoline, diesel, and jet kerosene) are petroleum-based.
Figure 1 - CO2 emissions by sector, World, 1990-2021 / Source: IEA (2023)
According to the International Energy Agency (IEA), in 2022, global CO2 emissions from transport grew by almost 3%, reaching 8 Giga tons (Gt) and nearly reaching pre-pandemic levels (Figure 2). Aviation was responsible for much of this increase, as air travel rebounded from pandemic lows. While hydrogen offers significant potential to accelerate the decarbonisation of transportation, it is best viewed as a complementary solution rather than a competitor to other low-carbon strategies. (Figure 3).
Figure 2 - 2022 global CO2 emissions from transport by segment / Source: IEA (2024) and author’s elaboration
Figure 3 - Hydrogen applications in the mobility sector / Source: Hydrogen Council
The hydrogen molecule: Production and applications
Global hydrogen production stands at over 75 million tons annually, mostly from fossil fuels like natural gas and coal. However, to unlock hydrogen’s full environmental potential, it must be produced using zero-carbon electricity via water electrolysis—yielding what’s known as green hydrogen.
Today, hydrogen is primarily used in petroleum refining and fertiliser production, while transportation and utilities are emerging markets. As global decarbonisation efforts intensify, hydrogen demand is projected to increase in the coming decades, with clean hydrogen potentially capturing up to 14% of future global energy markets.
The rate of hydrogen adoption will depend on the competitiveness of production costs and the deployment of enabling infrastructure at scale. Today, renewable hydrogen is two to three times more expensive than hydrogen produced from fossil fuels. However, production costs are expected to decline to $2.5 to $4.0 per kilogram by 2030, from today’s $4.5 to $6.5 per kilogram thanks to technology improvements, economies of scale, cost reductions along value chains, and carbon pricing policies.
"Overall, clean hydrogen holds significant market potential across energy systems. As a versatile energy carrier, it can store renewable energy, enhance grid stability, fuel stationary applications, power fuel-cell vehicles, and serve as a key feedstock for synthetic fuels in hard-to-abate sectors such as aviation and shipping."
Road transportation
Road vehicles account for about 74% of transportation-specific emissions (Figure 2). In 2022, private cars and vans were responsible for more than 25% of global oil use and around 10% of global energy-related CO₂ emissions. Hydrogen-powered fuel cell electric vehicles (FCEVs) offer substantial promise, with significant advantages over battery electric vehicles (BEVs) in terms of refuelling times and driving ranges. Refuelling times are much shorter; filling current models takes between three and five minutes and closely resembles the experience with a conventional vehicle. In contrast, recharging a BEV can take between 20 minutes to 12 hours, depending on the battery size, charger capacity, and depth of charge. Driving ranges vary but are similar to conventional vehicles (400-600 km). Fuel cells also provide higher energy densities, lower weights, and a lower material footprint than lithium batteries. Given these benefits, FCEVs are ideally suited for end users who require low downtimes, drive long distances, and carry heavy loads, such as taxis, buses, trucks, and heavy-duty vehicles.
However, widespread adoption of FCEVs faces significant challenges, including high ownership costs and limited infrastructure:
• Fuel cells are more expensive than comparable-sized light-duty conventional vehicles, even if leasing packages often include fuel, service, and maintenance, making the total ownership costs relatively similar. For heavy-duty trucks, analysts foresee that hydrogen could become competitive with diesel by 2030.
• Only about 1,100 hydrogen refuelling stations are operational globally, compared to over 2.7 million public charging points worldwide. Building a hydrogen fuelling station currently costs between $1.5 and $2 million, while an ultra-fast-charging electric vehicle station with a single 150 to 350 kW charger can cost between $85,000 and $250,000.
Next stop: Hydrogen trains
Rail is one of the most energy-efficient and clean transport modes. Trains carry about 7% of global motorised passengers and 6% of freight while accounting for about 1% of the overall transportation sector’s CO₂ emissions. As a reference, on a well-to-wheels basis, rail emissions per passenger average around one-fifth of those of air travel.
As old diesel trains are phased out of rail networks, hydrogen could become the answer to the sector’s complete decarbonisation. Hydrogen offers greater flexibility and affordability, particularly over long distances and in rural areas.
However decarbonising rail systems remains a difficult value proposition, with diesel trains still dominating in many countries. In 2021, among EU-27 countries, nearly 44 % of rail lines were still diesel-powered, compared to the near totality of freight and passenger rail locomotives in the US. So far, electrification has been the preferred decarbonisation option, but interest in hydrogen alternatives is rising. Hydrogen-powered trains have been in service in Germany since 2018, and pilot tests have been completed in Austria, the Netherlands, and Sweden. In 2023, France ordered twelve hydrogen trains to begin commercial operations by 2025, and Italy allocated €300 million to new hydrogen trains and associated green hydrogen projects. In February 2024, California announced a $127 million investment to double its hydrogen-powered passenger train fleet. It is important to note that while, so far, advanced economies have driven most hydrogen rail projects, developing economies have also recently started to invest. Notably, India has announced a pilot project to produce hydrogen trains in Chennai.
Cost is a key motivation for adoption. Hydrogen trains reduce emissions at a significantly lower cost than track electrification. While a new Alstom hydrogen-powered train can cost up to 11 million, electrifying a single kilometre of track could cost upwards of $1 million. Hydrogen trains are particularly valuable in rural areas, where fewer passengers tend to travel longer distances.
Another significant advantage of hydrogen-powered trains is their ability to operate as bi-mode systems on electrified and non-electrified tracks—offering flexibility as most rail lines remain unelectrified. They’re also more resilient to disruptions, as they can switch to fuel cells if the electric infrastructure fails.
However, infrastructure deployment and hydrogen's lower volumetric energy density than diesel are major constraints. Advancements in hydrogen compression and storage will be essential to improve scalability and cost-efficiency.
Shipping
Despite being one of the most efficient forms of freight transport, shipping remains a challenge for decarbonisation efforts. In 2022, the sector accounted for about 2% of global and about 11% of transportation-related CO₂ emissions, and it has in place a revised (now in line with the Paris Agreement) self-imposed goal of reducing emissions by 40% by 2030 from 2008 levels and being net-zero by 2050.
Thus far, electrification has been the preferred decarbonisation option, with battery-operated ships are already replacing vessels running on marine diesel oil (MDO) for short-distance operations like ferries. But complete electrification remains a problematic value proposition due to the volume of cargo that operators would lose to store enough energy for long-distance shipping. Large ships crossing oceans would simply need too many batteries. Hence, low-carbon fuels with high energy densities, such as hydrogen and ammonia, are expected to play a key role in the industry. On an energy content parity, while batteries require 64 times more volume than MDO, hydrogen and ammonia only need 8 and 3 times more, respectively.
Ammonia, a hydrogen-based molecule, can be combusted in an engine or used in fuel cells. It stores twice as much energy per volume as hydrogen and requires only mild refrigeration (-35°C), unlike hydrogen’s cryogenic needs (-253°C). However, its toxicity to humans and marine life raises important safety and environmental concerns.
Costs are critical as hydrogen-based fuels are still more expensive than conventional ones. Due to the added conversion steps, costs are even more significant in the case of ammonia. Although orders for new ships are starting to show a trend toward alternative fuels—in 2022, 90 (11% by tonnage) new-build orders were for ammonia-ready vessels, and three for hydrogen- ready vessels. Robust global hydrogen and ammonia networks to ensure that ships can refuel at any port will be key for the sector’s transition to a low-carbon economy. Policymakers must support innovation, deployment of enabling infrastructure, and the definition of appropriate safety standards and regulations.
To date, over 200 companies have joined forces in the Getting to Zero Coalition, which aims to achieve commercially viable zero-emission shipping by 2030 and full decarbonisation by 2050. According to the International Council on Clean Transportation, liquid hydrogen could fuel up to 99% of existing interoceanic routes between China and the United States with the addition of a single refuelling stop. As of 2022, more than 203 zero-emission shipping pilot projects had been demonstrated worldwide, up from 106 and 66 in 2021 and 2020, respectively.
Hydrogen powered skies
As international travel demand recovered after the Covid-19 pandemic, aviation emissions reached about 80% of their pre-pandemic peak. In 2022, aviation accounted for 2% of global energy-related CO₂ emissions and 11% of transportation-related CO₂ emissions. But its true climate impact is higher due to non-CO₂ pollutants like nitrogen oxides and soot. With demand growing over 5% annually between 2010 and 2019, scalable decarbonisation is crucial to meet net-zero goals by 2050. Efficiency gains alone are not enough—sustainable aviation fuels (SAFs), including hydrogen, are set to play a central role, though they currently make up less than 0.1% of fuel use. Hydrogen and drop-in fuels represent two competing pathways for decarbonising aviation, each with distinct advantages and challenges. Specifically, drop-in SAFs, such as biofuels and synthetic e-fuels, are compatible with existing aircraft and refuelling infrastructure, allowing for immediate integration into current fleets with minimal modifications, thus providing a near-term edge in commercial viability.
The advantages of hydrogen as an aviation fuel have been well-known for decades. Its mass-based energy density is three times that of jet fuel, and it is already used in space programmes. As battery-powered aircraft face weight and safety limitations, hydrogen offers a more scalable solution. Hydrogen can be used via direct combustion in jet engines or in fuel cells to power electric motors—or a combination of both.
However, the path to hydrogen-powered aviation is still taking shape and will require coordinated investment across value chains. All stakeholders must accelerate efforts to advance enabling technologies and infrastructure. The sector will need to adapt innovations from both the automotive and aerospace industries, focusing on minimising weight and cost. One of the most critical technical challenges is the safe onboard hydrogen storage while complying with stringent aviation safety standards. Addressing this will require the development of hydrogen-specific safety protocols and regulatory frameworks. Moreover, widespread adoption will depend on the availability of robust refuelling infrastructure. Since airports have concentrated fuel demand, onsite hydrogen production offers a promising solution to reduce logistical complexities and distribution costs.In 2023, the first test flights using fuel cell-powered electric motors took place. ZeroAvia flew a 19-seat aircraft with a hydrogen-electric engine on its left wing, while Universal Hydrogen flew a 40-seat regional airliner with a fuel cell powering one of the engines. In parallel, assessments of alternative propulsion systems have been conducted. Rolls- Royce and easyJet have performed a ground test combusting green hydrogen in a regional jet engine. Airbus has also designed and produced the first cryogenic liquid hydrogen tank prototype.
Conclusion
Hydrogen faces several critical barriers—particularly in storage, infrastructure, and cost—that must be overcome before becoming a transformative force in transportation. Hydrogen’s competitiveness in road transport will hinge on the total cost of ownership and availability of refuelling infrastructure. Heavy-duty and long-haul segments offer the most promise, with captive fleets enabling early adoption and improved station utilisation—though reducing delivered hydrogen costs remains essential.
In rail, hydrogen trains are well-suited for freight and regional routes where, due to long distances and low network utilisation, electrification is not viable. Their bi-mode capabilities offer added flexibility.
Shipping and aviation have limited low-carbon fuel options, representing a significant opportunity for hydrogen-based fuels. In maritime transport, hydrogen and ammonia can outperform battery ships and help meet emissions goals—but high fuel costs, cargo volume losses, and global refuelling infrastructure remain barriers.
In the aviation sector, synthetic drop-in fuels are promising but energy- and cost-intensive. Direct hydrogen use could also play a role, but the sector must adapt technologies from automotive and space industries while meeting stringent safety standards.
Going forward, innovation will be crucial to reducing costs and improving the performance of electrolysers, fuel cells, and hydrogen-based fuels. Progress is needed to address technological challenges around weight and hydrogen storage, particularly in the maritime and aviation sectors.
From a policy perspective, adoption at scale will require to:
• Integrating hydrogen into national and international energy strategies, with attention to geopolitical and market dynamics
• Implementing supportive policies, including carbon pricing and low-carbon targets, to drive market demand for clean hydrogen
• Address investment risks, especially for first movers, such as targeted and time-limited loans and guarantees
• Focusing on new hydrogen applications, clean hydrogen supply, and infrastructure projects
• Strengthening R&D and public-private partnerships to accelerate innovation and commercialisation
• Harmonising standards and removing regulatory barriers, while developing robust certification systems for low- and zero-carbon hydrogen.
Until now, technological limitations, economic barriers, and consumer preferences have slowed the large-scale adoption of hydrogen in transportation. However, emerging geopolitical drivers—particularly the urgency of climate change and sustainable development—are shifting the landscape. Global stakeholders must now define their roles in shaping this transition.
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