Zombie technologies of electric vehicles: e-roads
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Oct 31, 2019
James Carter

In the final article of our Halloween-themed series, James Carter explains why high costs and technical challenges make electric roads better suited to rail than cars

This is the fourth and final article in a Halloween-themed series in which we present four technologies that display zombie characteristics

We’ve all seen it: great new technologies with huge potential from a central promise to revolutionize what we do. However, each comes with a challenging list of problems that — when viewed objectively — relegate the technology to prototype form with limited commercial value. These problems could include available technology, cost, business model, and in some cases, the basic laws of physics.

However, these problems aren’t enough to stop hardy groups of individuals from continuing their development and promotion, fuelled by the promise of fulfilling those technologies’ potential.

New Mobility is no exception. In this short series of Halloween-themed articles, James Carter and Paul Martin analyze four technologies that display zombie characteristics.

Zombie Technology 1Solar panels on cars
Zombie Technology 2Hydrogen fuel cell cars
Zombie Technology 3Wireless charging

Zombie Technology 4: E-roads

The dream 

Drive onto a road with your electric vehicle and it self-charges through the road infrastructure, similar to an electric train or streetcar. This gives a vehicle an infinite range only limited by the infrastructure available. Drawing electricity straight from road infrastructure allows for much smaller batteries, thereby reducing vehicle weight and improving heavy duty load capacity.

How it works 

E-road infrastructure proposals usually take one of three forms: a wireless charging system embedded in the road; electrical contacts also built into the road surface, or an overhead catenary system with an electrical power contact (like a tram or streetcar). Some extend this dream by adding solar panels along the road, or even making them part of the road surface.

Why it should die (or how it could live)

The three types of e-roads all have a slightly different takes and unique advantages and problems.

  • Embedded wireless charging systems have the advantage of being contactless and frictionless. However, they can generally operate only at low power levels of around 3-11 kW, meaning that the vehicle must be on the road a long time to recoup any sort of charge. In fact, even at highway speeds where vehicles use low amounts of power, a small car will still use more energy than it can take on through the wireless e-road. While this can extend the range of the vehicle, the amount of power brought to the vehicle — sold at perhaps only 20¢ per kWh — makes any investment very marginal. In addition to their inefficiency, wireless charging systems are also very intolerant of mis-alignment — a few centimetres to either side can dramatically drop efficiency. In motion at highway speeds, such a fine tolerance of alignment, even by a highly skilled driver, is practically impossible; even the best driver-assist systems available today could not create the vehicle alignment necessary for consistent charging.
  • Embedded conductive charging, usually using a metal strip in the road, also is very problematic. While likely more efficient and somewhat tolerant of mis-alignment, high-power electricity transmission through an embedded metal road strip creates an electrocution danger for humans and animals, especially when raining. As well, the metal track can easily become clogged with road grime, dirt, leaves and, in winter, snow and ice, causing contacts to jump the metal charging track. The sliding metal contacts also create friction, reducing the efficiency of the vehicle, particularly at highway speed. And let’s not even talk about embedding solar panels in road surfaces: that idea was favoured only by people with no understanding of either solar panels or roads and has failed spectacularly where it has been tried as a result.
  • Catenary conductive charging, where an overhead wire is supported by a series of posts, similar to streetcars or trains, largely negates the problems of embedded conductive charging associated with a road surface location. It uses contacts on an overhead pantograph mounted on the vehicle, which is raised when it approaches the e-road. At highway speed, friction and extra aerodynamic drag lower the efficiency of this approach.

Despite the dream, all e-roads systems suffer from some common problems. The first is that the scope is limited to the infrastructure installation. Unlike, larger battery EV applications, which can be driven anywhere, the vehicle’s usefulness is restricted to that section of road where the e-road is installed. This makes a vehicle’s use case, when designed for this application quite narrow, especially if a smaller battery is fitted. 

The infrastructure and maintenance cost for any e-road application is very high, and OEMs, governments and private investors are very reluctant to support such technology when the return per kWh is so small versus the giant infrastructure costs involved.

To make matters worse, Scania and Volvo are the only main OEMs supporting an e-road system. This means interoperability among various heavy-duty OEMs is low. In direct competition to the e-road system, most heavy-duty OEMs are now supporting the CharIn/CCS High-Power Charging for Commercial Vehicles (HPCCV) standard, which allows ultra-high-power conductive charging for battery applications. This standard is far more usable and practical, while the general agreement among almost all OEMs ensures interoperability for almost all users.

Ultimately, e-roads will die due to lack of OEM support and the very high cost of infrastructure. If few OEMs support such a standard, no government or private investor will back such a venture, which ultimately means irrelevance.

Our Halloween conclusion

E-road ideas work far better on rail than road.

In this series

Zombie Technology 1: Solar panels on cars
Zombie Technology 2: Hydrogen fuel cell cars
Zombie Technology 3Wireless charging
Zombie Technology 4: E-roads

James Carter Vision Mobility

James Carter is Principal Consultant of Vision Mobility, a Toronto-based consultancy that provides services to OEMs, Tier 1s, dealers, startups, industry organizations and companies on strategies to succeed in a New Mobility environment. Prior to that, James worked for Toyota for 19 years in Australia, Asia and North America.

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