Commercial trucks constitute 18% of the greenhouse gas emissions in the City of Seattle. Moving freight without oil is one of the major technological hurdles for carbon neutrality. Smaller local deliveries may be made in battery electric trucks such as the Newton or the Zaptruck XL. But battery electric trucks have limitations, all related to the batteries. The weight of the battery packs displaces cargo capacity, limiting the cargo weight to battery power ratio. The process of recharging batteries induces electrical losses, and the batteries themselves require disposal and replacement at the end of their useful life. Battery power is fundamentally never as efficient as a direct electrical connection. Electrical trolley buses are the starting point for another solution for carbon neutral goods movement. Seattle, like many other cities around the world, has a network of electrical overhead contact systems (OCS) over city streets, directly powering buses on frequent routes. Electrical trolley buses are 100% electric and the technology has been in use for over 60 years. Could the same technology provide power to trucks?
As a matter of fact, it has. Mining operations, in the U.S. prior to early Bush-era cheap oil and to today in Southern Africa, utilize trolley trucks for heavy and steep loads. Electric traction has advantages over diesel in acceleration, hill-climbing and braking. If heavy mining trucks can be adapted for electric trolley operation, highway trucks can be designed for it as well. Trolley-powered trucks are used in the Ukraine and Russia for urban local deliveries. An electric-trolley powered freight hauling system has been proposed for freeway truck traffic to the Ports of Los Angeles and Long Beach.
Trolley trucks could be introduced in Seattle in conjunction with an expansion of the existing electric trolley bus system. The key enabling technology is a wireless smart meter, mounted on top of the truck at the connection point to the trolley poles, which would bill the truck’s registered owner for power supplied through the trolleys (an open trolley power system). City policies could favor the purchase of dual powered (electric trolley/battery or diesel) trucks. For example, all large city vehicles (fire trucks, garbage trucks under contract) could use dual power systems. When travelling on arterials with trolley infrastructure, the driver would raise the trolley poles (with the touch of a button) to directly use electric power and recharge on-board batteries. When turning onto a local street without trolleys, the driver would lower the poles and rely on a battery backup. Sound fanciful? A city serious about carbon neutrality should develop an open trolley infrastructure. In the excellent book “Transport Revolutions: Moving People and Freight Without Oil,” Gilbert & Perl argue that in the case of oil scarcity, “grid-connected vehicles” will emerge as a solution for mobility.
Real world scenario of how this could play out: the City has facilitated expansion of the electric trolley bus system to include all routes within city limits, and banned diesel buses. Every Safeway supermarket in the City is now on a trolley bus route. Instead of sending diesel-powered big rigs through city neighborhoods to supply the supermarkets, at each store Safeway could add a short section of trolley wire from the street to the loading dock. If the Safeway distribution center was on a trolley-powered street, the company could use trolley trucks for all deliveries to its Seattle stores. And the distribution center could be served by electrified freight rail for bulk food deliveries.
High-speed trolley wire could also be added to certain lanes of freeways, for bus and truck use. The Port of Seattle could also develop a program to promote trolley-truck usage for freight. There are many possibilities such as these yet to be explored for carbon neutral movement of freight.