Medium- and Heavy-Duty Vehicle Electrification in North Carolina

How many organizations and cities in North Carolina have or will soon have electric buses in their fleets?

The answer is nine.

Although light-duty electric vehicles (EVs) tend to get most of the fanfare, the medium- and heavy-duty electric market is also here, and here to stay. In the most recent webinar from our Exploring North Carolina Smart Grid project, Jacob Bolin, project manager of electric transportation at Advanced Energy, and Mike Rowand, director of technology development at Duke Energy, spoke about how medium- and heavy-duty EVs are driving transformation in the energy sector, providing cost savings and reducing emissions.

Driving Cleaner and Quieter for Less

Medium- and heavy-duty EVs already come in many shapes, sizes, duty cycles and use cases, and big industry players, from Amazon to UPS, are noticing. But why e-mobility, and why now? Jacob began his presentation by discussing the benefits of electrifying this segment of transportation.

Medium- and heavy-duty EVs share many advantages with their light-duty counterparts. For one, they are cheaper to operate and maintain thanks to reduced fuel costs and fewer moving parts. But they are also a significant grid asset: With their large batteries, they can support grid optimization by unlocking opportunities for managed charging, other vehicle-grid initiatives and resiliency dispatching during times of need.

Then there are the environmental and air quality prospects. In the U.S., transportation produces more greenhouse gas emissions than any other economic sector, and medium- and heavy-duty vehicles in particular have a disproportionate effect. Jacob noted that one line-haul truck emits the nitrogen oxide equivalent of 100 cars for each mile of urban driving. Furthermore, across the U.S., Europe and China, freight trucks represent less than 10% of all vehicles but roughly 40% of their carbon emissions, primarily due to high mileage and diesel engines.

When it comes to efficiency, medium- and heavy-duty vehicles have substantial room for improvement. A transit bus running on diesel gets the equivalent of about 5 mpg. An electric version could bump that number all the way up to 16.7.

Infrastructure Considerations for Medium- and Heavy-Duty Fleet Electrification

To match the variety of medium- and heavy-duty EVs is a variety of charging options: Plug-in, wireless and overhead systems are all in operation today. These larger vehicles, though, can require substantial amounts of power and a new approach to fleet management.

In his portion of the webinar, Mike Rowand of Duke Energy discussed infrastructure considerations for this class of vehicles. Compared to light-duty EVs, which today charge at a maximum of 350 kilowatts (and even that’s rare), larger vehicles, such as semitrucks, are being evaluated at rates exceeding 1 megawatt. Known as extreme high-power DC fast charging, this power draw is equivalent to a high-rise building or retail mega-center. In other words, just one or two trucks charging simultaneously could have comparable electricity demand to a 40- or 50-story building.

With this in mind, charging concerns for medium- and heavy-duty EVs go well beyond just the charging station. Particularly for larger vehicles, they must also include facility electrical infrastructure (internal switchgear, conduit, conductors, internal transformers, etc.); utility service infrastructure (transformers, capacity, etc.); distributed energy resources (renewable energy, battery storage, resiliency needs, etc.) and more.

This new landscape of evaluating medium- and heavy-duty EVs is more complex than the one for traditional liquid-fueled vehicles. For the latter, vehicle specification and acquisition, fuel purchasing and commodity risk management, and facility engineering and planning could all be pursued independently. With EVs, they’re interconnected and interdependent.

The vehicle being explored can influence facility needs, which can influence electricity rates, which can then, in turn, influence vehicle selection. And all of this is baked into usual considerations of total cost of ownership and site operations. There will be a learning curve for navigating how these pieces fit together, and it will be critical to simplify the picture as much as possible.

Mike spelled out the importance of careful planning and coordination by ending his presentation with hypothetical real-world scenarios of medium- and heavy-duty fleet electrification.

Looking Forward

In North Carolina and beyond, we hope—and expect—to see more medium- and heavy-duty EV deployments, particularly with demand for online delivery and e-commerce continuing to grow. Medium-duty EVs have already reached or are close to reaching parity with their diesel counterparts on a variety of characteristics, from operating costs to maintenance considerations to typical daily driving range.

To delve further into medium- and heavy-duty electrification, check out additional webinars from Plug-in NC and the North Carolina Clean Cities Coalitions. And for more information on smart grid topics, including previous webinar recordings, case studies and additional resources, visit