Electric Class 8 trucks could pay off in 3 years

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Carnegie Mellon University researchers study use cases for electric semi-trailer trucks, list research priorities to speed adoption of advanced vehicles.


Researchers at Carnegie Mellon University (CMU) say it may be time to start investing in electric semi-trailer trucks.

In their paper, Quantifying the Economic Case for Electric Semi-Trucks, published in ACS Energy Letters, CMU Assistant Professor of Mechanical Engineering Venkat Viswanathan and Ph.D. student Shashank Sripad compare the cost of traditional diesel semi-trucks to electrically powered ones. Their work examines the point at which electric semi-trucks become more cost-effective than diesel trucks.

Viswanathan and Sripad’s research demonstrates that the initial cost to invest in electric semi-trucks may be worth paying. In addition to reducing the transportation sector’s greenhouse gas emissions, switching to electric semi-trucks would have a strong economic case using a set of achievable targets.

A few unfavorable scenarios do not allow a meaningful payback period, but in favorable scenarios in which energy prices rise, the period is around 3 years or less.

“When the Tesla semi-truck was announced, it was important to understand how far it could go and what types of payload it could carry,” Viswanathan says. “We decided to use the framework we had previously developed for electric commercial vehicles and apply it to semi-trucks.”

In their paper, the authors examine the initial investment and the operating cost of a fleet of electric semi-trucks that can travel 500 miles compared with a fleet of diesel semi-trucks.

Electric trucks have a lower operational cost because they have increased energy efficiency for mobility along with a comparable or lower cost per unit of electricity compared to diesel. However, the initial price of the lithium-ion battery pack powering the trucks makes some investors pause.

“In spite of those initial concerns, there seems to be an economic case for transitioning to electric semi-trucks,” Sripad says. “However, to ensure favorable economics, important aspects like the low-battery pack cost, high cycle life, and low electricity price need to be ensured.”

Ultimately, the paper suggests meeting various targets to help with the transition to electric semi-trucks:

  • Optimize vehicle design to reduce battery pack size and meet 38,000 lb payload requirements
  • Lower battery pack price to less than $150/kWh to encourage people to invest
  • Keep electricity cost at or below $0.20/kWh
  • Enable 500kW rapid charging technology
  • Improve battery pack cycle life

The research was conducted, in part, at Carnegie Mellon’s Wilton E. Scott Institute for Energy Innovation where Viswanathan is an energy fellow.

Carnegie Mellon University