When I first heard, almost a decade ago, that trucks might be powered by overhead cables like electric trains and trolley buses, I considered it a fanciful idea. Now, after seven years of successful trials, mainly in Sweden, Germany and California, both on test-tracks and public roads, I reckon that it offers an effective means of decarbonising road freight. Others are more sceptical.
Let’s first consider the advantages of electric road systems (ERS). Top of the list is the efficiency with which it distributes low carbon electricity to vehicles – around 3.3 times higher than the use of green hydrogen as the energy carrier. The dynamic charging of vehicle batteries while on the road makes it possible to ‘downscale’ their size and weight, reducing the loss of carrying capacity, the demand for scarce battery materials and the capital cost of the truck, around half of which can be battery-related. The creation of e-highway corridors on busy routes would also relieve pressure on ‘static’ charging facilities where vehicles relying solely on batteries will require fast-charging during driver rest-breaks.
Critics of ERS mainly question its capital cost and safety. At €2-3million per km, the installation of catenaries on one motorway lane in each direction is expensive, but several UK, German and international studies have shown that this would still prove the most cost-effective way of decarbonising HGVs. The main safety concern is that overhead cabling might fall onto the road, harming road users. Automatic power cut-offs would minimise the risk of electrocution, but the cables themselves could pose a hazard.
This assumes, of course, that electrification will be by overhead catenary. Power can be transferred from below using induction loops or contact rails embedded in the road surface. French and Italian motorway operators favour these technologies, considering them to be safer, cheaper to install and maintain, and able to power cars, vans and coaches as well as trucks, thereby spreading the capital costs across a larger vehicle population. These surface-based ERS technologies, though, are at an early stage in their development and have had very limited piloting.
One of the biggest obstacles for ERS is its rejection by several European truck manufacturers. They are wedded to using batteries and hydrogen fuel cells as decarbonising technologies, dismissing ERS on various technical, operational and commercial grounds. They doubt the commitment of governments to electrify sufficiently dense road networks to justify carriers’ investment in ERS-enabled lorries. Some are uncomfortable with the degree of infrastructural dependence this would entail, but the need for dense networks of recharging, and possibly hydrogen-fuelling, stations makes such dependence inevitable on all paths to net-zero road freight.
Scania, on the other hand, belongs to a consortium funded by the UK government to study ERS, which recently concluded that it ‘will present the lowest carbon and most energy-efficient option to decarbonise freight.’ ‘A national ERS rollout’ for HGVs ‘would remove approximately 5% of the UK’s total greenhouse gas emissions’. Hence, my support for what once seemed a far-fetched idea.
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