There’s a potential speed bump ahead on the road to commercial electric vehicle (EV) adoption that few people are talking about. According to Jeff Wolfe, Tritium’s president of the Americas, by 2030 demand for commercial EVs will outstrip installed DC fast chargers (DCFC) capacity, the transportation industry will be unable to achieve electrification goals due to capital expenditure shortfalls, and there will not be enough engineers to install DCFC units. Wolfe isn’t just talking about these problem, he wants to start solving them today.
Tritium’s solution is to simplify and accelerate the installation of DC fast-charging infrastructure by developing modular DC subgrids that should not require much, or perhaps any, involvement from utilities or regulators. His DC subgrid plan can be implemented without getting the utility involved in most states, he said, because it all happens behind the meter and without discharging any power out through the meter.
To be clear, Wolfe isn’t trying to totally avoid working with utilities and governments, he just thinks the time pressure to get enough DCFC units up and running in time means finding solutions that don’t need to get them involved. “I’m all for working with the utilities, but we may need to work faster than the utilities are able to,” Wolfe said at the 2019 SAE COMVEC conference in Indianapolis in September. “Even when the utilities want to work faster, we’re going to be able to work faster [with this plan] than the regulatory bodies can work.”
Tritium has a dog in the fight, since it builds and sells the 50-kW Veefil-RT and the 350-kW Veefil-PK fast chargers. Tritium also engineered and will build the new Halo charger for Ionity that was unveiled at the IAA 2019 Motor Show in Frankfurt in September. “As a manufacturer of one of the products that’s going to cause this [DCFC shortage] problem, we hope to provide a solution,” he said. “We need our products to interact with the grid in a different way. We are working to build our products to require fewer interconnections.”
Wolfe’s proposed DC subgrid solution would run at around 950 V, “which is below a lot of UL standards, below a lot of code standards,” he said. It also uses a single AC/DC converter while having fewer interconnections than is typical for DCFC locations. All of the converters and interconnections in today’s grid makes installing a lot of them cost prohibitive and inefficient, he said, adding that the DCFC units that Tritium sells account for only about 30% of the cost of installation. The DC subgrid proposal reduces the other 70% to make the total cost of installation less expensive.
Wolfe gave an example of an Ionity site in Europe that has six 350-kW chargers, or 2.1 MW of charging capability. The transformer on site is only 1.2 MW, he said, because Ionity has figured out that the actual capacity at the site, between new vehicles coming in, plugged-in vehicles finishing a charge, and chargers not being used, only needs to be around 60% to the total capacity. “So, we can size the central AC/DC conversion for that 60%,” he said. “And if we happen to engineer or guess wrong, we can add more later on. It’s modular.”
In Wolfe’s proposed DC subgrid setup, solar or fuel cell power generation could be easily added, and stationary batteries could be used to reduce peak demand and level the load curve. Controlling the cost for peak usage is potentially more important than controlling the transformer size, he said. “We’re capping that transformer size, which will save us enough money in fewer interconnections to pay for part or all of the cost of the battery.”
Wolfe’s suggestions will require a lot of work from groups he does not have control over, an issue he recognizes. “Basically, we need to rebuild the grid. And that’s not on anyone’s calendar,” he said. If Wolfe gets his way, though, it will be.Continue reading »