Better the devil you know?

Trucks powered by liquefied natural gas (LNG) are no better for the climate than conventional diesel trucks, and pollute the air far more than manufacturers claim.

I was shocked to read that independent on-road tests – commissioned by Transport & Environment (T&E), Europe’s leading NGO campaigning for cleaner transport – show that LNG trucks are not a viable solution to reduce emissions of greenhouse gases (GHG) or air pollutants.

“To determine whether the suggested emissions savings can be achieved in the real world, T&E commissioned the Graz University of Technology to undertake testing of a conventional diesel truck and a gas-powered LNG truck,” reads the report’s* executive summary.

In terms of well-to-wheel GHG performance, the LNG truck that was tested delivered lower emissions savings than claimed by the manufacturer. “Over a 100-year global warming potential (GWP), the LNG truck achieved a GHG reduction of 7,5% compared to the tested diesel truck. When looking at a 20-year GWP time frame, the LNG truck had higher emissions than the diesel truck, resulting in 13,4% higher GHGs.”

It highlights that these findings run contrary to the industry’s claims that gas-powered trucks constitute a viable “bridge technology” which could deliver meaningful GHG reductions both in the short and long term. “As the results of this testing project show, betting on LNG trucks is counterproductive,” the report notes.

“The significantly higher global warming potential of methane over 20 years, compared to a 100-year timeframe, means that increasing the number of LNG trucks on European roads today would actually lead to an increase in global warming over the next few decades compared to the alternatives.”

Fedor Unterlohner, freight manager at T&E, says: “Gas trucks are a dead-end for cutting emissions and will even exacerbate the climate crisis today. Only emissions-free vehicles are capable of decarbonising trucking. It’s time for gas fuelling stations to be dropped from the EU’s infrastructure targets and for governments to stop incentivising the purchase of LNG trucks.”

The report highlights that gas trucks don’t fail only as a credible solution for reducing air pollutant emissions, but don’t improve air quality either. “The testing results are showing that particle emissions from LNG trucks, both particle mass and particle number, can be higher than those from diesel trucks.

“The tested LNG truck emitted particularly large amounts of very small particles, which are increasingly considered as the most harmful to human health.”

These cancer-causing particle emissions are also worse in cities and rural driving. In tests it emitted 37 times more ultrafine particles – which penetrate deep into the body and are linked with brain tumours – than the diesel variant. And while the gas truck performed better than diesel for nitrogen oxides emissions, it did not deliver the 90% savings that the truck manufacturer claims.

Unterlohner adds: “LNG trucks are held up as saviours of air quality, but tests show they pollute far more than manufacturers claim. They are also a lot worse than diesel for the smallest and most harmful particles, including in city driving, where they are used for deliveries. Ultimately, gas trucks are just another fossil fuel technology that can never clean up freight.”

Zero-emission trucks, like battery electric vehicles, seem to be the only option to take – but they do have their own set of challenges … And they aren’t very green if you charge them with electricity that is generated by coal stations.

I’m tempted to suggest that in South Africa we stick to the devil we know, but the reality is that everyone has to do their part if we are going to save the planet.

We just have to keep looking.

* Transport & Environment (2021). “LNG Trucks: a dead end bridge. Emissions testing of a diesel- and a gaspowered long-haul truck.” Retrieved from https://www.transportenvironment.org/discover/lng-trucks-adead-end-bridge/