Emissions targets for transport sector won’t be met by using natural gas alone

Using natural gas fuel combined with other methods could help the road freight and shipping industries meet emissions targets, according to a new white paper released by Imperial College London.

The new white paper, written by academics at Imperial’s Sustainable Gas Institute, Imperial’s Centre for Transport Studies and the University of British Columbia’s Clean Energy Research Centre, examines the potential benefits of using natural gas for ship and truck fuel. It looks at how a switch from heavy fuel oil and diesel could affect greenhouse gas emissions, air pollution, and cost to industry. In 2015, road freight – which includes long haul trucks – contributed 7% of global carbon dioxide (CO2) emissions, and ships contributed up to 2.5%. Both sectors also emit nitrogen oxides (NOx), sulphur oxides (SOx) and particulates, which contribute to air pollution and harm human health.

The paper shows that using natural gas to fuel vehicles and ships releases less carbon than diesel. However, the report found that some natural gases, like methane, leak as they move through the supply chain, which significantly reduces the benefit of switching fuel. 

The authors say switching to natural gas as a transport fuel could provide cost-effective emissions benefits and the technology is available, but it won’t be enough to reach long-term low carbon ambitions. Lead author Dr Jamie Speirs, from Imperial’s Department of Earth Science & Engineering, said: ‘The greenhouse gas benefits of natural gas as a transport fuel are useful in the immediate term, but must be coupled with additional energy efficiency measures and longer-term plans that include much lower carbon truck and ship technologies.’

Such measures for the road freight industry include the electrification of long-haul operations, more efficient logistics processes, improved aerodynamics and more energy-efficient tyres to reduce resistance. However, the report also notes that in recent years, regulations for trucks has improved their energy efficiency to an extent that switching to natural gas for fuel might not reduce the relative benefit of the switch. 

Shipping manufacturers can decrease the amount of energy used by vessels, and money spent on traditional fuel, by installing solar panels to supplement energy needs and using sails to harness wind power. Another method is to use barnacle-repellent paint to prevent build up on the hull and keep the ship streamlined.

Implementing these changes will help the shipping industry meet targets set by the International Maritime Organisation (IMO), which seeks to halve greenhouse gas emissions from ships by 2050 compared to 2008 levels. The road freight industry, which includes goods transport via trucks, is expected to work towards similar carbon reductions.