ACS News Service Weekly PressPac: May 20, 2015

Natural gas versus diesel: Examining the climate impacts of natural gas trucks

"Influence of Methane Emissions and Vehicle Efficiency on the Climate Implications of Heavy-Duty Natural Gas Trucks"
Environmental Science & Technology

Some major trucking companies are turning to natural gas to fuel their fleets — and to earn “green” credit among customers. But celebrating lower emissions could be premature, according to an analysis in the ACS journal Environmental Science & Technology. Researchers have found that converting heavy-duty trucks to run on natural gas could lead to negative climate impacts if steps are not taken to improve engine efficiency and reduce methane emissions from the fuel’s supply chain.

Burning natural gas emits less carbon dioxide (CO₂) into the atmosphere than other fossil fuels, but the process of getting natural gas out of the ground and delivering it through pipelines releases methane, a much more potent greenhouse gas than CO₂. So, Jonathan Camuzeaux and colleagues wanted to investigate the climate impacts of switching to natural gas in different types of heavy-duty trucks.

The researchers examined a range of assumptions for methane leakage and several different kinds of commercial, natural-gas truck engines. They calculated that switching heavy-duty truck fleets from diesel to natural gas could lead to worse climate impacts over the next 50 to 90 years than remaining with diesel due to methane’s high potency as a greenhouse gas in the near term. But, they added, reducing methane losses from the supply chain and improving natural gas engine efficiency could make switching fuels climate-friendly.

The authors acknowledge funding from the Robertson Foundation.

Making heavy-duty trucks “greener” by switching to natural gas will require changes to the fuel supply and engines.
Credit: Daniel Deitschel/iStock/Thinkstock