'E-highways' could slash UK road freight emissions, says study

The UK could eliminate the majority of the carbon dioxide emissions from road freight by installing overhead charging cables for electric lorries on “e-highways” across the country, a report by government-funded academics suggests.

The plan for a so-called electric road system would cost £19.3bn and put all but the most remote parts of the UK within reach of the trucks by the late 2030s, with the potential for the investment to pay for itself within 15 years, according to the report by the Centre for Sustainable Road Freight. The centre is backed by government research grants and industry partners including Tesco, Sainsbury’s and John Lewis.

The catenary cables, powered by the national electricity grid, would link to lorries driving in the inside lanes on 4,300 miles (7,000km) of UK roads through an extendable rig known as a pantograph – similar to those on the top of electric trains. The electricity would power the lorry’s electric motor, as well as recharging an onboard electric battery that would power them to their destinations beyond the electrified roads.

The engineering company Siemens and the lorrymaker Scania have already carried out extensive tests of e-highway electric road systems in Germany, Sweden and the US.

Officials from the UK’s Department for Transport were scheduled to visit the test sites in Germany in March, but the trip was postponed because of the coronavirus pandemic.

The road freight sector is a large contributor to the climate crisis, accounting for 5% of the UK’s carbon dioxide emissions in 2018, according to government figures, as well as pollutants from diesel engines that harm human health. Road transport was the sector with the largest increase in global greenhouse gas emissions over the last decade, according to the Committee on Climate Change, which recommended on-road charging for lorries in its latest report to parliament.

Battery-powered electric lorries and vans are already viable options for the short-range deliveries in urban areas that make up about a third of road freight usage. However, the other two-thirds – long-haul deliveries by lorries – are difficult to decarbonise because of range and weight requirements. The lithium ion batteries used in electric cars do not currently have a high enough energy density to be viable for long-distance haulage, meaning trucks such as Tesla’s planned Semi could require tonnes of batteries, denting their efficiency and raising their cost.

In contrast, a lorry fitted for electric roads would only require a battery of similar size to an existing Tesla car to be able to cover the vast majority of the UK, according to David Cebon, a professor of mechanical engineering at Cambridge University who co-authored the study.

Multiple lorrymakers are developing lorries running on hydrogen fuel cells, but the authors of the study argue that “green” hydrogen trucks would use three times more energy than an electric road system. This is because energy is lost at every conversion: using solar energy to make hydrogen and then a fuel cell to generate electricity again.

The electric road system would also have a major advantage over alternatives in that it would be possible to tax the electricity used by lorries, enabling the government to easily replace revenues lost from taxing diesel fuel, the report said.

“If you have an inefficient energy system, you build fundamental inefficiencies into your economy, which puts the country at a competitive disadvantage,” said Cebon. “You create efficiencies [by using the ERS] that give you financial headroom. The government can generate tax revenues through this scheme because it is efficient.”

The report suggests that a first phase of building work on the busiest roads could take two years, costing £5.6bn. However, electrifying those most popular routes alone would cover almost a third of the miles travelled by heavy goods vehicles in the UK. Later stages would bring the total cost to £19.3bn.

Lower energy costs are predicted to pay back vehicle operators for the investment in new vehicles within 18 months, while electrification infrastructure could pay back its investors – either government or private – within 15 years, the report said.