Ever since the Paris Climate Agreement, there have been incessant debates on the transport industry’s mammoth impact on the uncontrolled rise of global carbon emissions to date. This led to the industry being inundated with regulations directed at curbing its carbon footprint.
Local governments have also tried cajoling the transport industry to adopt low-emission vehicles and alternative fuels by providing tax benefits and grants for companies developing greener technology. One such scheme prevalent across several countries is the low tax rates for trucks that burn liquified natural gas (LNG) as fuel – based on the understanding that LNG pollutes less than diesel.
However, findings from a recent study conducted by Transport & Environment (T&E), a European NGO, show that the trucks powered by LNG do not fare better in terms of carbon emissions when compared to diesel trucks. The study examined three recent and popular LNG truck models – Iveco Stralis Hi-road, Volvo FH420, and Scania G340 – and compared their emissions to that of an average diesel truck in the market.
“The three LNG trucks tested emit two to five times more poisonous NOx than the diesel truck with the lowest test result when driven in a combination of urban areas, regional routes and motorways,” said the T&E report. “When driven in towns and cities, the gas trucks release two to 3.5 times more NOx than the tested diesel truck with the lowest emissions. Trucks powered by biomethane (biogas) would have the same air pollutant emissions as trucks running on fossil gas because the fuel characteristics are the same.”
The results are startling, as governments have largely been conducive of LNG-powered vehicles, with policymakers approving tax breaks and subsidies for businesses willing to move towards LNG trucks.
Apart from being a lot more caustic to air quality, LNG trucks also emit particulate matter – volumes that are comparable to diesel trucks. Though no contributor to global warming in itself, the microparticulate matter can get lodged within the lungs when inhaled, thus causing complications and in some cases, death.
Curbing NOx emissions is critical in Europe, especially in the wake of the Dieselgate scandal, which is estimated to have caused enough damage to air quality for it to result in 5,000 additional premature deaths annually across the continent. Most of the air quality deterioration happens in urban spaces, which also are more densely populated compared to the countryside.
Then there is the issue of people migrating towards industrialized regions in search of work and better living conditions. In Europe, roughly three in every four Europeans live in an urban setting, and the numbers are only going to increase as we move forward. Municipalities are realizing the issue and are bringing in sweeping reforms that include splitting cities into zones and banning old and highly polluting vehicle models from driving within central and highly traffic prone zones.
The research study on LNG trucks was carried out by Dutch applied science research organization TNO, which reported that in urban driving conditions, NOx emissions from all the three tested LNG trucks measured to be 39% to 117% higher than an average diesel vehicle tested earlier at the site.
These findings directly negate the claims of automakers, who argue that LNG trucks have negligible carbon emissions compared to diesel trucks. “The TNO reports show that these claims are not true. In fact, the Scania and Iveco trucks tested emitted quite large numbers of particles per kilometer during urban driving conditions,” said T&E in its report. “These emissions during urban driving are particularly worrying as they can have a significant impact on air quality in towns and cities.”
The EU policies see LNG to be a cleaner alternative in transport systems, which when the recent findings are accounted for, may not be not the case. The Alternative Fuels Infrastructure Directive (AFID) supports the development of infrastructure for alternative fuels, and it lists LNG to be one of the primary alternative fuels that can replace diesel as fuel for trucks. This has resulted in European truck manufacturers receiving up to €17 million in funding via various EU research grants for perfecting LNG powertrains.
European countries struggling to reduce carbon emissions despite massive tax cuts and regulatory measures, will need to wake up to the emissions reality of LNG trucks and look to cease schemes that encourage its adoption within the transport sector.
Chad Hillard
Do we know if the diesel powered vehicles used had an SCR after treatment system and did the LNG trucks have this as well?