Writing this major review for SAE has been a real eye-opener. I had the privilege of working with 19 experts, many world leaders in their fields. They provided technical inputs on topics as diverse as future battery technologies, critical metal mining, the impact of particulates on public health, green hydrogen production and balancing electrical demand.
I was expecting to learn about supply constraints for electrification, the value of active travel and the efficiency of public transport. What really surprised me was the huge potential of electric road systems.
Ramping up battery electric vehicle (BEV) production to fully decarbonize the automotive sector in time to meet climate goals will be a huge challenge. We simply don’t have the critical metal supply from current mining operations and, with current lead times, new mines won’t be commissioned quickly enough. Even if we do manage to electrify our road transport, this won’t solve the particulate pollution problem. Millions of people will continue to die from respiratory diseases caused by inhaling tiny particles produced by brake and tire wear.
Active travel is the clear winner for urban transport. Walking and cycling around cities not only eliminate greenhouse gasses and particulates. They also massively improves public health through increased activity levels – cutting heart disease, cancer and mental illness. Cities can transition to active transport by creating new road infrastructures that are far cheaper than other transport solutions while paying for themselves rapidly through reduced healthcare costs. I’m actually just launching another project that will address the need for new forms of lightweight vehicle that better integrate peoples urban travel needs.
Despite the huge scope for active travel for short and often urban journeys, these short journeys only account for 11% of greenhouse gas emissions. Decarbonizing the remaining emissions caused by heavy goods transport and longer journeys requires a different solution. The options are essentially public transport or automotive electrification. The cultural shift to active travel within cities will facilitate public transport by providing the ‘first and last mile’ transport needed for A-to-B journeys.
While hydrogen is often seen as the only solution for long-haul heavy vehicles, there is an alternative. Electric road systems (ERS) could provide an incredibly efficient way to electrify road transport for longer journeys. Systems with conductive rails on the road surface or inductive loops just below it have been developed. These can identify individual vehicles and energize short sections of road as they pass over, allowing each vehicle to be billed for just the electricity they use. If only the major roads are electrified then vehicles will still require batteries but they can be much smaller, to provide power for just the last few miles away from the highway. Techno-economic studies have shown that the cost savings from reduced batteries would more than offset the cost of the ERS infrastructure. Such an approach greatly reduces the current bottleneck of supplying the critical metals required for battery production.
https://www.sae.org/publications/technical-papers/content/epr2020014/If you want to find out more about this report it can be purchased directly from SAE International.
I had a similar idea for use with hybrid trolley / battery buses.
So you would use the overhead lines in the suburban regions and leave the urban centers clear (where you use batteries (but say 1/3-1/4 the size of a full battery bus).
The buses could hook on / hook off the conductive pairs using machine vision to guide them (easy as it is only 2 dimensional (X and Z)).
You could charge on the way to and from the terminii, thus you wouldn’t have to waste time charging that the terminii.
The main problem I can see is people crashing into the overhead lines, the cost of installing them and the need to get standards agreed quickly so machines and systems could interoperate.
Ideally, you could use this idea for long range trucking as well.
(As an emergency, you could add a diesel genset to get you home if things went pear shaped).