To reach climate neutrality by 2050, trucks and buses need to be entirely decarbonised. Battery electric (BEVs) and fuel cell vehicles running on green hydrogen (FCEVs) emit zero climate emissions and cause no air pollution, making these the only truly zero-emission technologies available to decarbonise trucks. There is increasing consensus among European truck manufacturers and industry stakeholders that battery electric trucks will become the dominant technology. As trucks are heavily used capital goods, the advantage of battery electric vehicles in terms of lower fuel and maintenance costs grows with increasing mileage, making them particularly competitive for long-haul transport.
Under the EU’s HDV CO2 standards, also combustion engine trucks running on green hydrogen (H2 ICE) are defined as ZEVs, as long as they emit less than 1 gCO2/kWh. While indeed H2 ICE trucks do not emit any climate pollutants, they do emit nitrogen oxide (NOx). To limit those air pollutants, H2 ICE trucks are fitted with an exhaust aftertreatment system, which – together with the combustion of lubricants (oils used to lubricate the internal parts of engines) – causes some marginal CO2 at the tailpipe. In total, these trace emissions are expected to be below the current regulatory threshold of 1 gCO2/kWh.
Gas, biofuels and e-fuels are often falsely touted as climate solutions to decarbonise new trucks. Yet each of these fuels still cause environmental harm, with biofuels and e-fuels also facing scarcity issues as other sectors rely on them to decarbonise.
- Biofuels: Growing crops to produce biofuels causes biodiversity loss, increased GHG emissions from deforestation, and threatens food security. Producing advanced biofuels from waste and residue feedstocks has the potential to bring emission savings, provided that stringent sustainability criteria are met. However, only very small quantities of advanced biofuels can be produced when strong sustainability criteria are applied. For example, 45% of Hydrotreated Vegetable Oil (HVO), a so-called ‘renewable diesel’, currently consumed is made from palm and palm derivatives. HVO made from waste or residues (e.g. used cooking oil or animal fats) is only available in very limited volumes and expected to be primarily used to produce sustainable aviation fuels (SAF). Biomethane is the other main biofuel raising interest from the trucking sector. It can only be sustainably produced in limited quantities, and methane slip can potentially wipe out all GHG savings compared to fossil gas.
- e-fuels: Producing e-fuels is a highly energy-intensive process which makes inefficient use of renewable electricity. Refuelling a conventional truck with synthetic diesel would cost 50% more and emit 3 times more GHGs than driving a battery electric truck in 2035. Production volumes will remain low for the foreseeable future, and would not suffice to meet demand from aviation, shipping, and the chemical industry, which have no alternatives to decarbonise.
- Fossil gas: Liquified natural gas (LNG) is just another fossil fuel. It offers only negligible greenhouse gas savings and no air quality benefits when used in trucks. But most importantly, gas trucks emit methane, particularly during cold starts. Though methane does not accumulate in the atmosphere, it is a far more potent greenhouse gas than CO2, with a global warming potential 28 times superior to that of CO2 over 100 years. Gas cannot be a transitional technology as it increases near-term warming instead of relieving it.
In the context of the HDV CO2 standards, the inclusion of e-fuels and biofuels would create regulatory loopholes as truckmakers have no control over how trucks will be refuelled over their lifetime. So they cannot guarantee emissions savings. Relying on bio and e-fuels to decarbonise trucks shifts the responsibility for and costs of the transition away from manufacturers onto fuel suppliers and fleet operators.
The CO2 standards for HDVs leave flexibility to manufacturers how they want to comply with the reduction targets. They can choose their own focus between producing more efficient internal combustion trucks or selling more ZEVs more quickly. While ZEVs will increasingly dominate the compliance strategies of truck makers, it can also be expected to see modest fuel efficiency improvements of 1.3% per year for heavy trucks and 0.5% in other segments.