In California, Siemens are testing electric trucks into the ports of Los Angeles and Long Beach. Electrified overhead power cables provide the power to trucks delivering to the ports.
The South Alameda Street demonstration is a one-mile ‘test track’, with the left lane coned off in both directions in Carson, California. A small construction-site mobile office sits approximately at the mid-point, under the Sepulveda Boulevard overpass. Here, another very short section of catenary allows for experimentation on or service of the installations on the trucks.
All three trucks can operate quite satisfactorily on electrical power supplied via the catenary power lines through the pantograph contact arms mounted above and behind the cabs. Both the catenary infrastructure and the on-board electronics and power controls to reduce the catenary voltage of 500–750 volts DC down to the 350 volts required to drive the trucks are owned and installed by the German Siemens.
There are three prime movers performing the testing in the catenary demonstration unveiled at the end of 2017. Two are Navistar ProStar ‘mules’ prepared by California-based TransPower.
These two trucks were purchased, then the engines and transmissions removed and the TransPower-developed electric powertrain installed. One of the ProStars is pure plug-in battery electric, the other has a CNG Ford 3.7-litre V6-powered generation set across the frame rails behind the cab that provides range extension by continually topping up the battery power.
The battery-only electric has a range of 64km, the range-extended truck offers the same mileage when running on batteries alone, but can operate for several hundred miles with the range extender in operation. The actual range varies with the CNG tank size: bigger tanks mean more kilometres.
The third prime mover is a Mack Pinnacle hybrid provided by Mack. While not yet commercially available, Mack has been developing a hybrid powertrain for heavy distribution trucks that operate on short hauls with traffic congestion. As hybrids, they have an electric traction motor to assist in accelerating the vehicle, which also functions as a generator in the regenerative braking mode to return electric power back to the on-board batteries. The 161hp peak, 94hp continuous (120–70kW) motor is sufficient to power the truck when the diesel engine is shut down, allowing for zero emissions when the truck is running under the catenary power line.
According to Mack, the prototype used in the demonstrations is a conventional Pinnacle DayCab model equipped with a proprietary and fully integrated plug-in hybrid electric driveline, offering significant fuel savings and emissions-reduction benefits even when the truck is operating outside of the eHighway.
While the technology demonstration goes forward, there’s opportunity for public comment. It will be interesting to gauge opinion on the visual pollution additional wires and poles introduced at street level. South Alameda Street is one of the least attractive routes imaginable, and the catenary does nothing to improve that.
But it doesn’t appear to impact the enthusiasm among the funding partners.
“This project will help us evaluate the feasibility of a zero-emission cargo-movement system using overhead catenary wires,” said Wayne Nastri, Executive Officer of South Coast Air Quality Management District. “This demonstration could lead to the deployment of e-highway systems that will reduce pollution and benefit public health for residents living near the ports.”