Most utility regulators understand that managed charging for light-duty electric vehicles (EVs) is really important. Instead of EVs charging at high-use times when serving customers is more expensive, charging can readily be moved to other times of the day when electricity is cheaper and the grid is not so constrained. Managed charging can also avoid imposing unnecessary additional costs of uncontrolled charging on other ratepayers.
Essentially, managed charging means being efficient with the grid resources used to charge EVs, and it becomes more important as we adopt more EVs. Americans bought nearly 1.4 million EVs in 2023, bringing the EV share of the US vehicle market to over 9 percent, up from 5.9 percent in 2022.
But historical assessments do not begin to reflect the scale of electrification that we will likely see in the next decade. The National Renewable Energy Laboratory reports that “Ambitious federal clean energy goals, including efforts to see EVs represent the majority of light-duty vehicle sales by 2030, could lead to 30 million–42 million EVs on the road by 2030 — more than 30-40X the number of EVs on the road today.”
This concern led some of us at RAP to wonder just how effectively charging programs around the country are actually managing charging. And this led to an even more basic question: How many EVs are actually participating in managed charging programs? Is it 3% or is it 30%?
Simple questions, right? Well, we found that, for various reasons, they are really difficult to answer. However, while we were researching and trying to find answers, we found some really good news. We found it in Minnesota, where the utility commission has developed a fairly simple approach to determining how many EVs in their state are actually participating in managed charging programs.
What follows is a discussion with Hanna Terwilliger, the Minnesota PUC staff person who figured this out for her commission.
RAP: So, Hanna, thanks for taking the time to discuss this. As I understand what you’ve done in simple terms is that you get state motor vehicle registration data and somehow correlate it with utility service territory maps to figure out how many EVs are in a utility’s service territory, and then how many EV they are actually managing. Can you explain how you came about doing this?
Hanna Terwilliger: That’s right. We wanted to know not just how many EVs in the state are participating in utility charging programs, but what percentage of EVs in each utility service territory are participating. One of the difficult things about service territory boundaries is they don’t really line up with other geographic boundaries like city limits or census block data. So, you have to get a little creative to get accurate counts of how many EVs utilities serve.
In Minnesota, our air regulators were already working with EV registration data, so I knew as a state agency we should be able to get that information as well. I knew we needed this more granular data to get accurate counts for each electric utility, and luckily we are able to do that with the help of our Department of Vehicle Services, or “DVS” as we call it.
RAP: So can you describe the pieces of this puzzle?
HT: Minnesota’s DVS gets VINs, or vehicle identification numbers, when people register their vehicles. You know — that long number on your dashboard at the base of the windshield. The PUC put in a request with the DVS for VINs for newly registered electric vehicles. They provided us with a list of those numbers along with the registration address for the individual vehicle.
Next we use the National Highway Traffic Safety Administration’s VIN Decoder. It is shareware that decodes VINs and gives us information about the vehicle, like make, model, manufacture year — for example, a 2021 Tesla Model 3 — and whether it is a plug-in hybrid or battery electric vehicle.
RAP: People’s addresses aren’t going up on a website, are they?
HT: No. We do not share address-level data.
RAP: So you don’t get that detailed?
HT: No. That is confidential information, and we don’t need it anyway. But we can share registration information by county, city, and zip code. We take the that data and have it “geocoded.” The Minnesota Geospatial Information Office, another state agency, does this for us. But this is also something that folks familiar with using Geographic Information Systems (GIS) can perform in-house if you have those capabilities. Anyway, this plots the zip code-level data onto a map, which allows us to combine it with the PUC’s utility service territory maps to determine the number of EVs in each utility’s service area. We’ve removed that address and identifying data, but then we add that information to the data set and publish it on our website for utilities to use without compromising customer data privacy.
RAP: That’s great. So you can develop locational data without going into such detail that would cross the line into privacy concerns. Can you tell us some of the ways that this data is used?
HT: At the PUC we use it to look at how utilities are doing enrolling EVs in managed charging programs. We’ve heard from cooperative utilities; they’re using the data to forecast where they might need distribution upgrades to accommodate load growth. They’re also using it to evaluate how they’re doing with their own load management programs. Investor-owned utilities — for example, Otter Tail Power Company’s Transportation Electrification Plan uses this publicly available data, and the Minnesota Department of Commerce uses it to comment on Otter Tail’s IRP.
RAP: So, this information is used in commission proceedings. Have you been thinking about future improvements to what you have started here?
HT: Some of the things we’ve added over the years, at the request of utilities, are standardized geographic identifiers — things like County FIPs (i.e., Federal Information Processing Standard) data that uses the same code so they’re able to match it up with other information. And one of the new things we just did this year is to make an interactive dashboard on our website.
RAP: Hanna, I want to thank you for taking the time to talk with us. What you have done for the Minnesota Public Utilities Commission is both really simple and elegant. You have made it possible for your commissioners to better understand how well utility managed charging programs are actually managing charging, and how well they are doing at getting EV owners to participate — really fundamental but important information.
HT: Thank you. Hopefully this can be a helpful guide for other states looking to help improve EV data for their utilities!
