High-Power Medium- and Heavy-Duty Electric Vehicle Charging

NREL enables medium- and heavy-duty electric vehicles (EVs) to charge in less time and at a reasonable cost through its development of megawatt-charging systems.

Truck charging stations of the future must provide reliable, high-power charging at an estimated capacity of 1 megawatt or more.

Illustration of multi-unit charging station with medium- and heavy-duty trucks parked at station units, one of which has a power transfer mechanism below the vehicle body.  Power distribution lines (13.8 kV AC lines) connect a utility tower to an AC/DC conversion unit (1 MW+ Multiport Network), which connects via high-voltage DC lines (e.g., 1,000 V DC) to each charging station unit, and also to a substation in the distance (not pictured).  The AC/DC conversion unit also connects to onsite photovoltaic panels (four panels angled on a platform), onsite generation (cube-shaped box), and onsite energy storage (rectangular shaped box). A thermal cooling unit (a fan enclosed in a cube-shaped box) connects to each of the station units.
Illustration by Al Hicks, NREL

Electric Vehicle Charging Characterization

High-power charging profiles can vary greatly between electric vehicle supply equipment (EVSE) and EV manufacturers. Understanding these differences will be critical for devising both control and energy storage integration solutions to lower the cost of charging.

To further this understanding, NREL researchers are working to:

  • Capture EV high-power charge profiles from commercially available EVs and EVSE under differing operating conditions to fully quantify charging loads seen by the grid
  • Characterize and analyzes EV fleet charging data
  • Identify several barriers to reliability for EVSEs.

These insights advance the state of high-power charging and benefits project partners by improving interoperability, charging reliability, and overall performance of EVs and EVSE.

Advanced Electric Vehicle Charging Hardware Systems

To further support EV growth, NREL is contributing to the advancement of interoperable, reliable, and fast charging hardware systems by designing and operating a high-power DC charging hub integrated with the grid to standardize EV chargers and site equipment. The insights generated by this effort will provide a pathway for industry to better understand the necessary development stages for a high-power DC-coupled charging hub.

As part of this effort, NREL researchers will:

  • Conduct reviews of different station power architectures for both AC-hub and DC-hub approaches
  • Validate the DC charging hub hardware, including DC-DC converters and DC-AC inverters, and software systems within the station and with the grid at megawatt scale
  • Develop low-power, control-hardware-in-the-loop and high-power, power-hardware-in-the-loop experimental platforms to understand scalability challenges
  • Determine station design requirements for DC bus distribution and site energy management systems
  • Design and demonstrate practical controllers to facilitate the flexible expansion of charging hubs serving light-, medium-, and heavy-duty vehicles.

Electric Vehicle Charging Standards

NREL researchers are working to develop new charging standards to support electrification across vehicle types and applications that require higher charging power while still supporting the grid. NREL actively supports efforts to develop a new high-power charging standard for medium- and heavy-duty vehicles called the megawatt charging system (MCS). MCS will facilitate charging capacity up to 3.75 megawatts—seven times higher than the current light-duty fast charging technology, which peaks at 500 kilowatts.

EV charging equipment evaluation will ensure the new standard is interoperable, meaning multiple manufacturers will be able to design and build parts that work together. Interoperability is critical to ensuring broad, consistent access to charging stations, and it will allow electric vehicle manufacturers to have confidence in station compatibility as new models come to market.

Site Planning and Design

Accelerating the deployment of EVs will also call for the expansion of infrastructure needed to support them. NREL researchers can help assess en-route charging, as well as associated planning, infrastructure, operation, and maintenance options, for on-road and non-road vehicles, aviation, rail, and marine applications.

NREL’s EV infrastructure tools help researchers develop customized EV infrastructure design and optimization strategies, conduct analyses of proposed refueling centers and depot charging leveraging utilization of the current fleets, and determine potential grid impacts.


Andrew Meintz

Chief Engineer for Electric Vehicle Charging and Grid Integration