The opportunity of road electrification for trucking
Energy efficiency, environmental conservation, resource limitation: many growing concerns call for the transportation sector to embrace a future without fossil fuels. Still, finding a valid alternative to petroleum has proven to be very difficult. The main issue? Electric vehicles (EVs) - the most promising green option in terms of energy security and emissions reduction – still lack a sufficient energy storage and are thus unsuitable for long haul freight. Engineers and entrepreneurs soon realised that electrifying vehicles would have not be sufficient: the solution? Electrify the roads themselves.
An electrified road (e-Road) is a transportation infrastructure which ‘‘delivers the electrical power to charge EVs efficiently while stationary or even in motion, using specific conductive or contactless charging systems”: thus, an e-Road can serve ordinary vehicles and, meanwhile, power electric ones. Let’s see how.
The state of art
e-Roads rely mainly on two types of technology: a conductive catenary system or an inductive recharge infrastructure.
As for the former, the ancestor of today’s catenary e-Roads is the well-known trolley bus, first invented by Siemens in the far 1882. Since then, conductive powering has much developed in terms of flexibility: nowadays, electricity can reach the vehicle both from a conductive strip placed at road surface or via an overhead pantograph (the most promising solution for heavy trucks).
The latter is also based on a very old idea (that of powering vehicles through an onboard storage of energy, dating 1842), that was revitalised by a novel invention: contactless recharge. This technique consists in using a Wireless Power Transmission system (WPT) to recharge EVs in movement, so to overcome their dependence on frequent plug-in charges. In particular, the Inductive Power Transfer technology (IPT) has shown great performance and applicability: here, power is transferred via induction between two magnetically coupled coils, one placed under the pavement (transmitter), another at the bottom of vehicles (receiver). Such recharge can happen statically, in parking lots or at traffic lights queues, or even dynamically (highway lanes).
The benefits of e-Roads
Road electrification has incredible advantages in terms of energy efficiency and lowered emissions: according to a study by Siemens, these systems have an energy efficiency of 77%, compared to 62% of battery-powered trucks and 29% of hydrogen fuelled trucks. And, since e-Roads eliminate the inherent limitations of EVs (i.e., little autonomy, time-consuming recharge), these infrastructures also promise to foster a more widespread use of greener vehicles.
Some more technology-specific advantages are to be mentioned: catenary conduction systems are very durable (several decades) and require relatively low maintenance; plus, we already hold much knowledge about this technology (nowadays very common for trains, trams and buses). At the same time, IPT technology permits to reduce the battery size of electric vehicles, which eventually leads to equally diminished cost, space, energy consumption, lithium usage and road wear.
The challenges ahead
Just like any revolution, road electrification is not free of challenges. On this matter, the trickiest problem is the construction of the infrastructure itself, which entails large initial investments and multiple technical difficulties, such as ensuring a successful recharge; integrating new facilities into the existing road structure without mining its performance; ensuring swift, cost-effective maintenance in the long term.
More specifically, some of the problems with catenary systems are that electric trucks and electric cars need to have separate lines, and that overhead infrastructures often encounter resistance from locals, which consider them “visually invasive”. Similarly, IPT technologies require a very delicate phase of design and implementation: if not successfully integrated into the pavement, the fragile IPT facilities will not provide sufficient recharge and may even alter the road’s ordinary service.
Where, when, and the next steps
But who are the brilliant minds that are already implementing such emergent technologies? In these early stages, Sweden has shown to be the absolute forerunner in road electrification. In 2016, it was inaugurated the world's first e-Road, featuring an overhead line system, and still here took place the first trial for a wireless electric public road, in December 2020.
Germany is equally advanced in the use of overhead catenary systems and is now testing wireless technologies in the city of Karlsruhe. At the same time, Italy is taking steps to electrify the A35 highway in Lombardy, using both the afore mentioned techniques.
In light of the above, it seems that e-Roads really hold the numbers to finally overcome the fossil fuel conundrum, enlarging the benefits of electric vehicles to a much broader scale. Thus, road electrification appears not only as a brilliant invention, but also an urgent step the sector must take in order to foster a de-carbonised future.