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Aona Stuart reports on electric highways and their potential environmental impacts

Railway overhead electric cables are installed across the UK as part of the electrification of the rail system. In 2020 the Centre for Sustainable Road Freight published a white paper titled Decarbonising the UK’s Long-Haul Road Freight at Minimum Economic Cost (bit.ly/3rYPlah), regarding the proposals for similar structures on UK highways – ‘electric highways’, or e-highways.

The proposals include an electric road system, which would encompass overhead electric cables to charge heavy goods vehicle (HGV) batteries, emissions capturing tunnels and barriers near residential areas, electric car-charging forecourts and a review of speed limits. They would be completed in three phases, ending in the 2030s and covering 65% (13,808km) of HGV-km roads, as shown in Figure 1 below.

Potential benefits

While metric tonnes CO2 equivalent (MtCO2e) emissions reductions have occurred in the power and industry sectors, Climate Change Committee data (bit.ly/2ZnE0Ey) shows that the surface transport sector is the highest emitter of CO2e, at 117 MtCO2e per year. Completion of the e-highway proposal would lead to a reduction of approximately 13.4 MtCO2e per year, while the increase of electric vehicles (EVs) due to the ban on the sale of new petrol and diesel cars post-2030 will save approximately 300 MtCO2e between 2030-2050, according to the government’s 10 Point Plan for a Green Industrial Revolution (bit.ly/3pnDBfS). The EV MtCO2e savings are dependent on an attractive market choice.

Bloomberg’s Electric Vehicle Outlook Report 2020 (bit.ly/3preGrN) predicts that there will be 54m global sales of EVs in 2040, compared to 2.1m in 2019. The e-highway proposal, in conjunction with an increase in EV use, would save between 434 MtCO2e and 568 MtCO2e by 2050, based upon e-highway proposal completion by 2030 and 2040 respectively. These savings would lead to a reduction in climate effects.

Emissions capturing tunnels and barriers near residential areas, electric road systems on 65% of HGV-km roads and an increase in use of EVs could help to improve air quality and reduce noise near residential areas. According to Ahanger et al.’s 2017 paper ‘Reduction of air pollution levels downwind of a road with an upwind noise barrier’, this would reduce concentrations of nitrogen dioxide (NO2), concentrations of particulate matter (PM2.5 and PM10) and road noise emitted by vehicles near residential areas. A decrease in noise levels, NO2, PM2.5 and PM10 near residential areas may also reduce the biodiversity impacts on surrounding fauna.

“Completion of the e-highway proposal would lead to a reduction of approximately 13.4 MtCO2e per year”

Areas of concern

It is important to remember that while e-highways may have benefits in the long term, construction will cause climate effects in itself – for example CO2e emissions from the carbon-heavy activities involved in producing and transporting materials (such as cement production, steel production and shipping). In addition, the vegetation clearance that would likely be required for car-charging forecourts could have an impact on the surrounding landscape, and the electric road systems for HGV-km roads may lead to visual impacts for passengers. This could be mitigated by constructing electric road systems on a single lane and planting emission capturing tunnel exteriors with vegetation, although these options have not been explored in any policy papers.

While it is true that a reduction in noise and pollution would benefit biodiversity in a broad sense, the risks to bird and bat populations could actually increase, due to interference from the electric road system overhead power cables on HGV-km roads. The increased land take for car-charging forecourts also has to be factored in when it comes to calculating the effects on surrounding fauna – and in addition, the e-highway proposal may be exempt from the 10% Biodiversity Net Gain in the Environment Bill, as it would be a classed as a major infrastructure project and covered by the Planning Act 2008 (as amended). Furthermore, the success of e-highways in reducing climate impacts would primarily rest upon the capacity and decarbonisation of the electricity grid.

E-highways could help the UK to reach net zero by 2050 and reduce climate change impacts, but all of these issues would need to be properly addressed – and the environmental assessment system perhaps even split into regions, in order to ensure that all potential impacts, mitigations and assessments of the likely effects across the country can be accurately and comprehensively captured.

Aona Stuart is a graduate environmental consultant at WSP and a member of IEMA Futures.

Image credit: Getty