Road electrification becomes reality in Germany
Updated: Sep 2, 2021
We largely discussed about how road electrification and catenary technologies are destined to change the world of transport, but, as any ramble about the future, it may have left the lovers of practicality – a treasurable value for those who work in logistics – a bit sceptical about its actual viability. So, to dispel any of your “yes, but…” we will bring you on a short trip: on the A5 highway, in the South of Germany.
We are located a few miles away from Frankfurt am Main, in the prosperous State of Hesse - which, in addition to being the financial capital of Europe, is the second most densely industrialised region in Germany. Predictably, Hesse features a highly strategic and efficient motorway network, for a total of 24 motorways in 21,100 km2 (8,100 sq mi), which strongly backs its effervescent economy.
However, with 135,000 vehicles daily – of which 14,000 trucks – the A5 is one of the most heavily polluted motorways in the country, so that making it sustainable has become an absolute priority.
To tackle this problem, in August 2017 the State of Hesse commissioned the well-known multinational Siemens to build a ten-kilometre overhead contact line for electrified freight transport (precisely the A5 autobahn between the Zeppelinheim/Cargo City Süd interchange at the Frankfurt Airport and the Darmstadt/Weiterstadt interchange).
The e-Highway, which first opened in May 2019 and entered service during summer 2020, has so far been used by five R 450 hybrid trucks equipped with pantographs, supplied by the well-known Swedish truck manufacturer Scania. This latter has also been responsible for vehicle maintenance and data collection during the trials.
As of today, the stretch of electrified road is planned to be extended by seven kilometres, while Scania will deliver seven more pantograph-equipped trucks. This enlargement, due by the end of 2022, will bring to a total of twelve kilometres in the direction of Darmstadt and five kilometres towards Frankfurt.
How it works
Still, we know that to fully convince you, we have to take you inside the technology – as, alas, we cannot take you into the truck (yet).
In brief, the electrification system used on the A5 is composed of three parts: energy supply, pantograph, and hybrid drive technology.
The first one exploits a two-pole catenary system, which leads to a level contact wire to provide stable current transmission even at high speeds. The energy supply for overhead lines derives from substations equipped with medium voltage switchgear, power transformers, rectifiers, and controlled inverters (to feedback the electric energy generated by the vehicles’ regenerative braking).
Then, the pantograph transmits energy from the overhead contact lines to the electric motor of the truck, and can be easily (dis)connected, both automatically and manually, to the contact wire at speeds up to 90 km/h. In addition, the pantograph automatically disconnects in the event of evasive manoeuvres or if the indicators are used.
The hybrid drive technology allows the truck, once it leaves the electrified stretch, to convert back to its traditional combustion engine. The type of hybrid drive used has no restrictions here, and can range from biodiesel, to battery, to fuel cells etc., according to the customer’s preferences. Moreover, the electric motors of the e-Highway trucks also enable recovery of the vehicle’s braking energy like a traditional hybrid car.
Looking beyond Hesse
The great energy-efficiency results of e-Roads encourage for an additional spread of this technology, inside and outside Germany.
In fact, after the A5 trial, other two similar trials have been conducted in the country (the A1 in Schleswig-Holstein and the B462 in Baden-Württemberg), and this amount is destined to grow: estimates show that if a third of the German motorways were electrified, 80% of the country's heavy road transport could go electric, so that the German environment ministry has suggested that 4,000 kilometres of motorways could be electrified in the close future.
Eventually, when looking at the future of e-Roads outside German borders, the major challenge that will have to be overcome is for sure interoperability: experts warn that in order to build an electrified road network at European scale, some form of standardized solution will be required, and an equal effort of coordination will be asked in respect of international, transport corridors.