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25 August 2017

Siemens tests eHighway for electro-trucks, potentially solves battery problem

By Jack Vernon

Siemens has been commissioned by the German state of Hesse to build an overhead contact line for electrified road freight, on a 6-mile stretch of highway that will supply electricity for the electric drivetrain of hybrid trucks. The ‘eHighway’ concept was originally presented in 2012, and now looks like a sensible way of electrically powering trucks and reducing their emissions. Haulers could save enormous sums on fuel costs, if highways authorities can see the environmental benefit and foot the bill to adopt the technology – perhaps through a public-private partnership.

Trucks have presented one of the most difficult challenges to those looking reduce vehicle emissions. According to the Environmental Protection Agency (EPA), in 2015 large and medium sized trucks accounted for 24% of all transport emissions in the US. Finding a solution for reducing truck emissions is difficult because of their enormous weight. Unlike cars and lighter vehicles, they do not make good candidates to be powered by batteries – unlike the types of electric vehicles consumers are currently being directed towards as the main solution to reducing their transport emissions.

This is because the average car weighs 4,000 to 6,000 pounds (1,800Kg to 2,700Kg), whereas a fully loaded truck can weigh up to 80,000 pounds (36,000Kg). A typical truck fuel tank holds 190 gallons of diesel and uses around an average of 1 gallon every 5 to 6 miles – giving it a range of around 950 miles per refuel. Given that batteries are considerably less energy dense than a fuel substance like diesel, they would take up far more space and weight in the truck than is currently dedicated to storing diesel, reducing the total potential hauling capacity of the vehicle.

The Siemens eHighway cable system enables a truck to be driven electrically without using the electricity in its batteries. In the original 2012 project in Sweden, truck company Scania adapted two trucks with a diesel-hybrid drive capable of running on electric power from the overhead cable when available automatically. The trucks then switch to diesel power at the very start and end of a journey on smaller roads that don’t have the power lines. The trucks used in the original project could demonstrate a top speed of 55mph while being driven by the electricity from the overhead cables.

Using cables to electrify the vehicle also means a far less dramatic redesign than a battery-powered truck may require. Asides from the addition of a roof mounted cable connecter and an electric drive train motor, the vehicles used as part of the project are no different to the rest of those in Scania model range.

Electrifying trucks with battery storage would mean a more fundamental redesign of the truck itself to fit the large volume of batteries that would be required, than adding the roof connector required to connect to the power cable. The batteries would also come at a far greater total expense than the modifications required for adding the eHighway tech to the truck – although this cost maybe offset by the reduction in fuel costs enabled by running solely on electricity. Adding batteries may also adversely impact a trucks handling capability.

However, the battery powered truck concept is by no means dead. Tesla is set to unveil its electric truck design in September. Very few details are currently available about the truck, as to its size, range, and battery capacity, apart from the fact that the model will go into mass production in 2019-2020.

It is worth considering that the approaches are not mutually exclusive and both eHighway’s and Tesla’s electric trucks may both work successfully together. Trains and trams have been electrified for more than a hundred years, but now those same concepts are being applied to electrically power trucks. Many roads already have electrified tram and rail lines, providing a template that in some cases might be easily and inexpensively modified to add eHighway or a similar system.

Siemens eHighway, if it were to become a widely adopted solution, shifts the focus of tackling the problem of truck emissions away from the hauling companies and onto the authorities that govern highways. Adding electric cables would take large infrastructure investments from those authorities, they would be taking on the brunt of the costs of funding the infrastructure to enable electrically driven truck vehicles, and would lose out on diesel taxes. However, they might look to recover these losses from the haulers.

The cost of installation is obviously a large barrier. The critical argument in justifying the investment into eHighway is the pursuit of truck emissions reduction. Areas that might most benefit from the investment are those towns and cities that lie in the pollution corridors of major highways – and so a local authority will be able to use that as a justification for installing the infrastructure.

Air pollution from highways has been shown to be one of the most significant causes of ill health in the densely populated areas surrounding the highways. In 2016, Beijing announced that it would build a pollution ventilation system to help tackle the issue, showing that governments are already looking for serious alternatives to tackle this issue. Popular truck routes such as between ports and other major distribution centers would make for sensible highways to upgrade – and full deployments of electrified roads sound unfeasible.

A number of national governments have now laid down commitments to ban the sale of gas driven vehicles. Germany has set a date of 2030 with the UK and France choosing 2040. Governments will need to start acting swiftly if they are going to be able to meet those commitments. This pressure on regulators may well mean Siemens’ eHighway system picks up a wave of new contracts for the product in the coming years.

The other major trend in the trucking industry, is the gradual move towards autonomous driving and truck platooning. Riot covered the European Truck Platooning Challenge in 2016, which saw a convoy of trucks autonomously drive in a platoon using an 802.11p WiFi standard to communicate with each other. This allows the trucks to drive closer to each other, reducing air resistance and the total fuel cost for those trailing the front-runner by 15%.