Driving decarbonization

EU heavy-duty trucks leading the way

The effects of climate change are increasingly clear, and the urgency to act and act now is evident. Quantitative targets and limits are in place to drive the transition to a low carbon economy, such as those in the Paris Agreement, the European Green Deal and the Fit For 55 package. To meet these ambitions, we all recognize the importance of fast-tracking CO2 emission reductions in the road transport sector to secure the maximum climate benefits as fast as possible, as economically as possible, allowing all available technologies to play their part.

At Westport Fuel Systems, we have developed a technology based on our proprietary HPDI™ fuel system that is optimized to enable the most advanced internal combustion engines to operate on hydrogen. H2 HPDI™ is a cost-effective, high-performance, high-efficiency solution that enables an accelerated adoption of hydrogen in the heavy-duty mobility sector.

As per the European Commission’s proposal for a Regulation setting CO2 standards for new heavy-duty vehicles (HDVs), this technology would be recognized under the revised “Zero Emission Vehicle” (ZEV) definition. We welcome and support this definition, which sets the “ZEV” threshold at 5g/ton-km of CO2. This “ZEV” threshold gives fleet operators access to the benefits of the “ZEV” label across a broader range of high performing vehicle solutions, and in doing so supports the move away from diesel trucks and accelerates the transition to low carbon transport. Further tightening of the “ZEV” threshold would push fleet operators to keep diesel trucks on the roads for longer, slowing down the EU’s decarbonization efforts.

The Commission proposal for “ZEV” at 5g CO2/ton-km works, for fleet operators, consumers, and the climate.


“90% by 2040 means that the vast majority of new trucks and long-distance buses coming on the market will be zero emissions, powered by batteries, fuel cells, or even hydrogen-powered internal combustion engines.”

Frans Timmermans, former Executive Vice President of the Green Deal and EU Commissioner

The current landscape

The road transport sector currently contributes approximately 20% of the European Union’s CO2 emissions , and heavy-duty vehicles serving the freight sector and public transport account for 28% of this total. To meet the Paris Agreement goals, the sector will need to reduce emissions intensity by more than 80% in less than 30 years. More immediately, the sector's emission intensity must fall by roughly 30% by 2030 .

The Paris targets will not be met if current trends continue. This is a serious challenge, but it is also an opportunity for EU manufacturers, industry, and decision-makers to work together to meet the challenge we are faced with, delivering on the Paris and Green Deal promises in a constructive and positive way for the planet and the industry.

The “ZEV” label conveys valuable benefits to qualified vehicles, and in turn, to fleet operators. Access to more vehicles with the “ZEV” label is a key tool in incentivizing adoption of the cleanest, highest-performing vehicles across the heavy-duty road transport sector.

ImageH2 HPDI™ – A fuel system for high power, high efficiency, pilot-ignited hydrogen internal combustion engines for the heavy-duty market

The challenge

With over 6 million heavy-duty trucks in the EU and an estimated 30% rise by 2050, ensuring that new trucks utilize all clean technologies available, including hydrogen internal combustion engines, is of the utmost importance if we are serious about this challenge.

Achieving carbon neutrality is a huge undertaking for the heavy-duty road freight sector, accounting for 28% of the EU’s road transport emissions and still using diesel for 96% of its final energy demand1.

Of all EU fleet operators, 99% are small and mid-size enterprises (SMEs), so the affordability of vehicles and solutions is key to cut down road freight emissions while retaining competitiveness. To facilitate a viable, practical, affordable route to decarbonization, fleet operators need access to the broadest range of technologies that can meet simultaneous needs, including:

A ZEV threshold of 5g CO2/ton-km will help make the economics of low carbon HDVs more viable for more fleets.

1 Includes diesel blended with biodiesel

5g CO2/ton-km: the road to a better future

To achieve these challenging objectives, we are developing high performance hydrogen internal combustion engine systems for heavy-duty vehicles (HDVs) that outperform other clean technologies, such as fuel cells, in terms of market readiness and cost-effectiveness. These hydrogen engines provide an attractive alternative to decarbonize HDVs without sacrificing the vehicle efficiency that is so central to fleet economics. A transition from fossil-fueled engines is critical for commercial road transport, and a new generation of advanced internal combustion engines can hasten hydrogen adoption.

Within the European Commission’s Regulation setting CO2 standards for new HDVs, a key element is the label assigned to vehicles that meet the “Zero Emission Vehicle” (ZEV) definition. In its proposal, the Commission has taken a pragmatic approach to a revised definition, setting a threshold of vehicles less emitting than 5g CO2/ton-km.

The Commission proposed threshold for “ZEV” labelling is well aligned with the overall trajectory for decarbonizing the HDV sector:


Reduce total HDV CO2 emissions by 30% by 2030


Reduce total HDV CO2 emissions by 80% by 2050


Reduce the average CO2 emissions of new HDVs by 90% by 2040


Set the threshold for “ZEV” labelled new HDVs such that CO2 is reduced by >90%

European Commission trajectory for decarbonizing HDV sector

Why is the “ZEV” label important?

At 5g CO2/ton-km, the “ZEV” label plays a key role for European small and medium enterprises (SMEs): vehicles that attain this label are eligible for several key benefits, most of which are conveyed to the fleet, and in turn the consumer. These benefits are operational and economic, and play a pivotal role indriving the widespread adoption of low emission trucks. Among them are sought-after privileges, such as:

The “ZEV” label conveys a number of fleet operator benefits arising from transport policies and regulations. These benefits are key market enablers stimulating adoption of hydrogen solutions.

What technologies are “ZEV” candidates?

At the 5g CO2/ton-km limit, it is only a limited number of solutions that are conceivable, therefore there is a significant technology chasm between even “Low Emission Vehicle” (LEV) threshold and the “ZEV” one. The technologies that have the capability to attain the “ZEV” threshold share some similar attributes:

  • All require new fuel/energy infrastructure
  • BEV and FCEV require whole new powertrain systems and manufacturing and supply chains
  • H2 ICE technologies retain manufacturing assets for internal combustion engines
  • All reduce tailpipe CO2 by more than 90%
  • All reduce diesel usage by more than 90%
  • None can operate on diesel alone (in the absence of electricity or hydrogen)

The 5g CO2/ton-km “ZEV” threshold is not an open door to a myriad of solutions, it remains a technologically demanding limit while offering the diversity of benefits that will aid market adoption.

A 5g ZEV threshold is not an open door

“ZEV” at 5g is attainable by only a limited number of technological solutions. Other solutions are unlikely to even reach the “LEV” threshold, including conventional dual fuel H2 ICE. Based on scenario for subgroup 5 LH.

The Commission's proposal of a 5g CO2/ton-km threshold is a challenge for most existing technologies. Only a select few — battery electric (BEV), fuel cell electric (FCEV), spark-ignited hydrogen internal combustion engines (ICEs), and a limited subset of pilot-ignited hydrogen ICEs — stand as potential candidates to achieve the “ZEV” label at this level. Should the threshold be lowered, it could effectively place the “ZEV” label out of reach even for the most advanced hydrogen engines.

When compared through a narrow lens of tailpipe emissions only, the fuel cell electric, spark-ignited hydrogen engine and pilot-ignited hydrogen engine powertrains show varying levels of tailpipe CO2. However, on a broader, well-to-wheel basis, the differences in efficiency of hydrogen use has a significant impact on total CO2. In scenarios where the cleanest, 100% renewable (green, electrolytic) hydrogen is used, the disparities between these technologies are minimal – highlighting why high efficiency can overcome the small differences in tailpipe emissions. If hydrogen with a higher carbon intensity is used, the higher efficiency of pilot-ignited engines helps mitigate the carbon intensity, leading to lower overall CO2 emissions.

Mission Profile Weighted CO2 Emissions

Comparison of Tank to Wheel (Tailpipe) and Well To Wheel CO2 emissions for hydrogen and diesel powertrains. Westport Fuel Systems analysis based on a 5 LH subgroup HDV over VECTO mission profiles, using fuel carbon intensities taken from JRC WTT v5.0.

The 5g CO2/ton-km "ZEV" threshold recognizes that efficiency is a key metric for hydrogen use, setting a pragmatic balance between challenging tailpipe limits and acknowledging the broader emissions picture.

Access to a wider array of vehicles and technologies that are eligible for the “ZEV” label increases both the utility and economic affordability of low carbon solutions, for even the most challenging vehicle segments. In turn, this will result in greater adoption rates, faster displacement of diesel use, support for capacity growth in new fuel/energy infrastructure and accelerated reduction in the carbon footprint of HDVs.

This wider array of “ZEV” vehicle solutions enables European transport operators, including SMEs, to optimize technology choices to the business and cost needs of their operations: cost-saving potential is the main driver for road freight carriers to make decarbonization investments.

EU Heavy Duty Road Freight in Numbers


Of the EU’s road transport emissions


Road Carriers operating across the EU


Of the 500,000 Road Carriers across the EU, 99% are SMEs


Of SME Road Carriers have a projected growth of +47% freight movement between 2015—2050


The cost saving potential is the #1 incentive for SMEs to decarbonize fleets

Driving decarbonization forward

Considering these insights, the Commission's proposed threshold of 5g CO2/ton-km emerges as a rational redefinition of the “ZEV” label, one that should be retained.

While representing a significant technical challenge, the Commission proposal broadens the horizons of truck operators by offering them access to a more extensive array of low carbon vehicle solutions. It enables operators to make informed choices, aligning vehicle specifications with both economic and operational imperatives, all while driving forward the imperative mission of decarbonization.

A “ZEV” threshold at 5g CO2/ton-km works, for fleet operators, consumers, and the climate.

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