From Trolleys to e-Highways? Paving the Road to Eco-friendly Transportation

While electric cars, bikes, and scooters might be an everyday staple to an urban environment as ways to help with GHG (greenhouse gasses) emissions, an often overlooked contributor is long-haul trucks. 

According to the European Environmental Agency (EEA) indicator assessment, road transport GHG will increase by 32 % by 2030 compared with 1990 marker levels, even with existing measures. Long-haul journeys on highways (>310 miles) are almost exclusively made by trucks powered by diesel engines, especially those connecting ports and airports with distribution centers. 

 

A chart of US CO₂ emissions by transportation and vehicle type. Image used courtesy of EPA [data] and Fleming et al

 

As the world strives for greener technology, one potential solution to help with long-haul trucks is e-Highways or electrified highways. 

This article will look at what precisely an e-Highway is, who is pioneering this technology, and what they have done so far in electrifying roads for long-haul trucking. 

 

What Makes an e-Highway?

Typical, what makes a general highway an e-Highway is the use of an overhead electrical wire system that supplies heavy load vehicles with electricity to drive long miles without stopping to plug into charging stations. Rather than manufacturing a heavy electric vehicle from scratch, e-Highways would use the existing road infrastructure and turn any heavy truck into a proposed plug-and-play electric vehicle. 

 

Managing E-Highways

With the support of major global players, including Cisco System Inc., Huawei Technologies Co. Ltd., Honeywell International Inc., AT&T Inc., IBM Corporation, Schneider Electric SE, and others, e-Highways hope to pick up speed and take truck electrification to the next level sooner rather than later. Despite the interest and company backing, e-Highways have some challenges to overcome. 

Creating an e-Highway takes a lot more than connecting combustible engine trucks to an overhead wire infrastructure.

 

An example e-highway system. Image used courtesy of Siemens and the California Energy Commission

 

The adaptation to a smart electrified system requires further development in:

• Hardware and power systems, like electric batteries or hydrogen cells as a complete replacement for fossil fuel or as a hybrid REF (renewable energy fuel) power system
• Software for control, monitoring, management, and communication between components
• Deployment services, whether on the cloud or on-premise
• Technologies to improve road safety, manage traffic, collect data, and reduce infrastructural damage

When you first look at the system for an e-Highway, you might think the electrification system is similar to conventional cable cars; however, it is not identical. It needs innovation to take it to the next level beyond cable cars or trolleys. 

Hoping to do just that, two German companies, Siemens Mobility, in collaboration with Continental Engineering Services (CES), and Traton, are heavily invested in preparing the technology and the infrastructure to reshape everyday product transportation through e-Highways. 

The future of road freight transport implemented by these companies in many aspects still resembles historical trolley systems, at least when viewed from afar; however, the rails are missing. To take that next step towards integration, Siemens and Traton have a unique electrification smart pantograph system.  

 

Siemens Plans to Electrify 4,000 km (~2485 miles)

First off, let's take a look at the solutions from Siemens Mobility. Recently, Siemens hopes to mobilize its rail electrification experience. In tandem, CES intends to provide automotive capabilities so the companies in partnership can cover the most used 4,000 km (roughly 2485 miles) of the 13,000 km-long German highway infrastructure with an overhead wire grid. 

Siemens' "trolley" trucks will have a smart pantograph equipped with sensors that enable the device to stick out, retract, and "hover" above ground while connected to the overhead wires at speeds of up to 90 km/h. 

 

Siemens' e-Highway plan infographic. Image used courtesy of Siemens

 

Decades of successfully using trolley cars and the relatively low cost of creating the infrastructure can cover the busiest highway kilometers, optimizing the efficiency of such systems up to 80%.

 

Roof-mounted Smart Pantographs

Unlike pantographs used in trolley cars and open-pit mines, which are limited by their close positioning to overhead lines, these devices are mounted to extend and make the system viable at speed, and to be put away when not in use.

Trucks can exchange power when passing by on uphill or downhill sections and refeed the braking power to the e-Highway system or the power grid. They could run on a combination of an electric battery or hydrogen cell and a combustible engine system or be fully electric to use on standard non-electrified roads.  

Smart pantographs are a technological milestone that can be roof-mounted on other vehicles, including buses, making for an extra opportunity to reduce GHG produced by multi-passenger vehicles.  

 

Traton Hybrid Trucks

Another solution comes from Traton. Traton's e-Highway, which currently takes place on a track near Frankfurt am Main, is still in the testing phase. 

However, the initial results of the effect on carbon emissions reduction are encouraging. If the project proceeds according to plan by 2022, the A5 highway between the cities of Frankfurt and Darmstadt will have hybrid trucks driving in one lane, while the rest of the vehicles will use additional lanes. Trucks would have a battery sufficiently charged to enable successful overtaking while the pantograph system gets off and back onto the power grid. 

 

The pantograph system can extend and retract to charge. Screenshot used courtesy of Traton

 

Motivated by the success of the Swedish Scania truck used in the testing, Sweden is also looking to implement e-Highways locally and expand the truck trolley grid beyond German borders.

 

Can We See Massive Highway Electrification Soon?

Enjoying the convenience of clean, safe, and quiet trolley systems are regaining popularity as fossil fuels fade into the background. Electrified highways complement other carbon-reducing transport modes and fit into the transitory period without significantly disturbing current motorway infrastructure and regulations. 

Pantographs were once quite limited in their structural design; however, smart mechatronics has helped many devices lessen structural vibration and improve stability and deployability. 

Smart pantographs are already used on train systems across Europe as a low-cost diagnostic kit for maintenance and preventing failure occurrences; they could also enable the creation of lightweight power and monitoring systems for e-Highways.

However, trucks packed with hybrid power inevitably cost a lot more than standard fossil fuel trucks. Even if the overhead grid is placed as planned, the main question is: how many truck drivers will purchase the vehicles or the batteries to use it. 

Despite the e-Highway goal being far-reaching and not in the near future, it will be interesting to see if other solutions and technologies come about or if this solution can actually take off, especially in the US.