If fast charging is available, the competitiveness of battery electric trucks compared with diesel trucks can actually improve with larger trucks, according to a new study by Björn Nykvist and Olle Olsson from the Stockholm Environment Institute (SEI).

In a study published in the journal Joule, the two researchers model high-power fast charging for trucks, enabling smaller batteries. They show that the economics of battery electric trucks per ton-kilometer improves with greater weight, driven by increasing load capacity as well as increased energy savings as a function of weight.

Nykvist and Olsson

They also show that previous findings that the competitiveness per kilometer is worse for heavy trucks than for lighter trucks are very sensitive to assumptions about the battery cost per kWh and lifetime of the battery pack.

Given the rapid development of batteries, we conclude that the economic feasibility of heavy battery electric trucks might have been generally underestimated.

—Nykvist and Olsson

Nykvist and Olsson explore variations across a set of three central battery pack parameters: battery cost, cycle life, and specific energy.

• Parameter set 1 (PS1) is broadly representative of conservative and slightly older assumptions used in the literature analyzing electric trucks by using Li-ion batteries (US$300/kWh, 1,000 cycles, 125 Wh/kg).

• Parameter set 3 (PS3) is broadly representative of an optimistic outlook that takes into account recent literature on Li-ion batteries (US$100/kWh, 5,000 cycles, 175 Wh/kg).

• Parameter set 2 (PS2) represents the arithmetic mean for each parameter between PS1 and PS3 (US$200/kWh, 3,000 cycles, 150 Wh/kg).

In line with previous analyses, they show the conservative PS1, battery electric truck competitiveness clearly worsens with greater GVW. However, using the more optimistic PS3 reverses the result: BEV truck competitiveness now improves with GVW. The midpoint values (PS2) indicate BEV truck competitiveness has no significant trend as a function of GVW. In other words, the truck segment is very sensitive to battery specifications.

When costs are modeled per ton-km, then the result is that the competitiveness of electric trucks improves with GVW, independent of assumptions made about the battery pack.

Their model also indicates that if the parameters of PS3 are actually reached, then heavy electric trucks can be competitive in absolute terms both per ton-km and per km.

… contrary to the conclusions previously drawn in the literature, these results suggest that if high-power fast charging is available, thereby allowing for smaller batteries to be used, BEV trucks can be feasible in the heaviest categories. Assuming no or limited fast charging necessitates significantly longer range and, thus, larger batteries.

—Nykvist and Olsson

Resources

• Nykvist and Olsson, (2021) “The feasibility of heavy battery electric trucks,” Joule doi: 10.1016/ j.joule.2021.03.007