12 AVENUES WINTER 2019 TRANSPORT TECHNOLOGY T ransport of aggregate represents the biggest cost to aggregate companies. It’s also the operational factor with the greatest environmental impact in terms of greenhouse gas production. If gravel trucks could use electric engines, charged by power made from no-emission sources like nuclear, hydroelectric or wind, that environmental impact would be cut significantly.  Avenues recently spoke to different manufacturers to get their thoughts on electric power and to learn of their plans in this area. “While there’s been some discussion about electromobility in construction applications, most of the work on electro- mobility is currently focused on applica- tions like refuse, local pick-up and delivery and so on,” explains Roy Horton, director of product strategy at Mack Trucks. “The duty cycles of these applications align more closely with electric trucks’ operating range and charging requirements.” On the other hand, adds Horton, heavy- haul and construction companies, particu- larly gravel haulers, are typically focused on productivity and cycle times: in other words, how many loads they can haul per shift or per day. “The recharging require- ments of electric trucks do not yet align well with their needs,” he says. “In addition, these applications would require higher energy usage, meaning more energy storage would be needed to be able to perform the job that the customer is currently achieving with diesel.” Horton adds that switching to elec- tric gravel trucks would also mostly likely require an aggregates company to change the way it does business, having to integrate the necessity of charging requirements based on range into work schedules, change maintenance timelines, conduct driver training and so on. “This is another reason why refuse is a good starting point, as their operations typically require fewer changes,” Horton says, adding that Mack has provided no indication of plans to develop electri- cally-powered gravel trucks. Caterpillar has also not publicly stated any intent to develop electric drive systems for highway trucks. However, the firm has been making diesel-electric large mining trucks for many years and currently offers two models with capacities of 290 and 310 metric tons. “These trucks use a large diesel engine to drive a generator that powers elec- tric wheel motors,” explains Mark Sprouls, a Caterpillar trade press relations rep. “They do not use a battery electric drive system. Additionally, they are much larger than the 90-metric-ton trucks that are the largest used in North American quarries.” Indeed, Caterpillar discontinued its manu- facture of all highway trucks (vocational trucks) several years ago. “The business forecast didn’t support continued manufac- ture of the line,” Sprouls reports. “Navistar, the manufacturing and assembly partner in Caterpillar’s vocational truck venture, closed the plant where the trucks were being built. Caterpillar made plans to start manufacturing the trucks in what was then a Caterpillar facility dedicated to building excavators, but that plan was not executed.” Caterpillar also discontinued making diesel engines for highway trucks some time ago. John Deere/Nortrax declined to comment on its development or non-development of electric heavy-haul trucks. GOING GREEN ON THE ROAD Experts weigh in on whether electric gravel trucks will ever take the road – and provide updates on heavy equipment By Treena Hein A CAT 988K XE – the company’s first electric drive wheel loader – loading a Cat truck