Report measures diesel vs. battery electric mixer truck power

Source: Concrete Products

Concrete Products’ Craig Yeack takes stock of the energy metrics and costs behind diesel fuel and battery electric power for ready mixed delivery in July’s column, “Are We Ready for Electric Concrete Trucks?” In the most comprehensive such examination to date for North American producers, he presents the comparison in terms of Btus, a common unit of measure for diesel fuel and electric power output. Using National Ready Mixed Concrete Association figures, a yard of delivered material consumes 1.08 gallons of diesel, equating to 148,371 Btus. Conversion to useful power for motion and hydraulics via the diesel combustion cycle is about 36 percent efficient in ready mixed operations. Hence, delivery of 1 cubic yard of concrete requires ~53,400 Btu (or, 148,371 x .036). With approximately 3,412 Btus per kilowatt-hour, the average delivery of 1 cubic yard requires 15.65 kWh of power.

“Right away, we can see the lithium-ion battery size has to be huge,” Yeack observes, citing the 3 cubic yard per trip limit, for example, the 50 kWh battery powering a Tesla S electric vehicle would present. Four round trips per day at 10 cubic yards each would require a mixer truck with 626 kWh capacity. That power requirement suggests a 4 metric ton battery to power a mixer truck for a productive day of duty on a single charge—cutting legal payload up to 2 yards per trip.

Given the limitations of lithium-ion battery power storage and output, Yeack examines the potential of sodium-ion battery alternatives. With their rapid recharge cycles, the latter are emerging in the electric vehicle universe and hold potential for mixer trucks in the coming years. “Are We Ready for Electric Concrete Trucks” concludes with a breakdown of diesel and electricity cost variables, noting how battery power could invite more than $1/yard savings in concrete delivery under current market conditions. The column is posted here.