The Critical Bottleneck to Heavy-Duty Vehicle Electrification: Getting Past the Grid Capacity Challenge

Despite a growing network of public charging points across the world, heavy-duty truck electrification is a slow-going transition, with some stakeholders putting the market today at the level of maturity that regular Electric Vehicles (EVs) reached 5 years ago. Today, there is a stock of ~15,000 eTruck chargers globally, with much of this being concentrated in the Asia-Pacific region—the limited proliferation of eTrucks and eTruck chargers can be attributed to the unique needs of heavy-duty EVs compared to light-duty EVs. This includes power output, supporting charging infrastructure, and operational considerations.

Many vendors are taking key steps in expanding the charging infrastructure for eTrucks, such as Kempower, Power Electronics, and Siemens, but there is an inherent challenge that both the Electric Vehicle Supply Equipment (EVSE) vendors and Charge Point Operators (CPOs) must tackle. This is the grid capacity challenge: the grid upgrades and grid access required for peak time charging are an obstacle, as widespread electrification will place heavy strain on the existing electrical grid without meaningful upgrades to anticipate the growth of eTruck use.

Although this is an ongoing challenge for the industry, the limited use of eTrucks today has led stakeholders to focus first on their technical charging requirements to ensure they are ready for the inflection point in adoption. Currently, the Combined Charging System (CCS) is the basis for Direct Current (DC) charging standards in North America, rated for up to 500 Kilowatts (kW), but the Megawatt Charging System (MCS) is rated for up to 3.75 Megawatts (MW). This increase will be needed to satisfy the energy demands of larger eTruck batteries, but in practice, most MCS chargers will output around 1.5 MW. A key detail in this transition is that these are not physically compatible standards due to different pins, so a CCS plug cannot connect to an MCS socket and vice versa. In response to this incompatibility, eTrucks that adopt MCS plugs will feature both MCS and CCS sockets, allowing them to use both types of chargers and be flexible during the transition period to MCS-based architectures.

While the transition is not completely laid out yet, there is at least a general consensus for MCS charging. However, the industry is less aligned on how to tackle the grid capacity challenge, with solutions such as Battery Energy Storage Systems (BESS) and on-site or near-site generation frequently mentioned as a potential solution to mitigate the strain of heavy-duty EV charging on the grid. But these solutions will have a limited impact: a BESS is most effective when installed chargers have lower capacities, but eTruck charging will not meet this criterion. On-site generation will have minimal impact on peak energy demand, with the most optimistic forecasts showing that solar panel generation would only be able to offset 10% of a site’s peak power draw, and only for a few hours of the day.

Slow grid connection and infrastructure upgrade processes mean that stakeholders need to find a way to overcome grid challenges soon, as the spread of eTrucks and charging stations will only further slow these processes in the future. As CPOs endeavor to build charging networks along freight corridors, they will also have to deal with a fractured landscape of network operators with their own bureaucratic procedures and policies. Some more innovative solutions have been proposed to address the grid challenges in the face of these further complications:

• Electric Road Systems (ERS):
  • By allowing vehicles to charge while they are driving through either induction technology, conduction connections between the vehicle and road, or catenary lines, stakeholders could increase access to charging and lower the need for high battery capacity in eTrucks. This has the benefit of distributing the power demand across a larger area and time period. ERS has made some progress in some countries in Europe, as well as Israel and the United States.
  • However, for many regions, ERS is an unrealistic solution with limited government support due to a preference for other public charging infrastructure funding. There was a time when more funds could be diverted to ERS, but it is now a limited opportunity for addressing the grid challenges in the time frames required.
• Battery Swapping:
  • This solution has the benefits of reducing the “charging” period to as little as 5 minutes, diluting power demand across longer time periods, and extending battery life with more gradual and controlled charging. China is the leader for this technology, with over half of eTrucks sold in 2023 featuring it, and stakeholder engagement in further plans for expanding swapping stations.
  • While advanced in China, other regions are much less mature in battery swapping technology and infrastructure. Some vendors have solutions and partnerships in this domain, but utilization is minimal and expansion into the heavy-duty segment is even more so. Time horizons for battery swapping to be a realistic part of the solution range from the late 2020s to early 2030s.

Both of these other solutions lack the speed of implementation to support planned expansion of eTruck fleets across the world, so the burden of encouraging adoption will require a focus on segments with lesser reliance on public charging infrastructure, such as depot or destination charging. Supportive regulations and investments in grid infrastructure must also be a priority to accelerate the heavy-duty EV transition, and enable other segments such as en-route charging to flourish as well.