Submetering Electric Vehicles in Apartment and Condos

We recently looked at installing EV infrastructure in a condo building parking deck and as we were leaving the resident asked us: “What about the meter?” She had been told that if she wanted to install an EV charging station she would have to have it submetered, but she was given no further guidance from the HOA. Did that mean by the local utility (Georgia Power), or with a simple digital submeter, or with a web based digital submeter, or what about a networked EV charger that also could meter energy? And once it was submetered who was going to bill for the energy consumed? I don’t think most HOAs and Apartment management companies know the answer or even how to frame the question!

As we were leaving the front desk attendant took us to look at an existing EV installation that had been done about 6 years prior. You can see from the image below that they used a simple digital sub-meter that displayed the energy consumed…but who was reading it and then billing the resident? Nobody knew anything about that installation.

The second picture shows the EV electrical infrastructure from the EV electrical panel to the assigned residents parking spot. They used a NEMA 14-15 receptacle which is great, but how do you prevent the EV charging station from being stolen?

There are several approaches to this problem and below are some of the most common we have found:

  1. Community installs Community EV charging equipment and infrastructure and EV residents pay a flat monthly fee that covers some or all of the electricity cost that the community pays for (no submetering)
  2. Community installs EV charging equipment and infrastructure that community owns at Assigned EV charging spaces. EV residents pay a flat monthly fee that covers electricity cost and EV equipment and infrastructure (no submetering)
  3. EV resident pays for EV charging equipment and infrastructure to assigned parking space. Community installs submetering equipment and billing solution to charge the EV resident for electricity they consume.
  4. EV resident pays for EV charging equipment (networked and submetered) and infrastructure to assigned parking space. Community ensures adequate space and access to electrical panels. An example of this solution can be seen here from ChargePoint with their CPF50 solution. In this option, the network solution handles all billing.

We then built the below Excel table with some of the following assumptions and additional notes:

  1. The average driver drives 7,000 miles per year (SWAG)
    1. The second image shows what the costs would be like if half the drivers were Uber/Lyft/etc drivers driving 30,000 miles per year (blended average of 18.5k miles per year)
  2. The “Miles/kWh” metric is specific to different types of EVs. More efficient EVs will have higher miles/kWh. We assumed “3”. You can find the different values from this link (and calculating using their “X kWh/100 mi” metric, which we think is kind of silly)
  3. Cost per electricity is 12 cents/kWh and there are 10 EV drivers
  4. For Option 3 and 4 (networked and/or sub-metered) adequate cell or wifi signal exists to get the data to the cloud. We threw in $500 for a wifi booster
  5. We aren’t assuming any additional electrical work needed to add additional electrical panels. If that’s needed, it would be needed across all solutions (with the exception possibly of Option 1).
  6. Monthly fees for Options 1 and 4 are based on discussions with others who have experience in the space. Monthly fees for Option 2 and 3 are arbitrarily chosen by us.
  7. Option 3 – the sub-metered option doesn’t really exist in a nice commercial package that we have found ( possibly with the exception of the option from Koben Systems where we got the image at the top of the post). It would be easy to come up with the hardware solution by using technology from a provider like Accuenergy; however, the challenge becomes how to easily bill the resident for energy consumed without a bunch of people (who cost money) doing the work.
  8. Any type of community charging should probably require some type of keyed access (physical key or card or phone) otherwise a resident or guest who hasn’t paid a fee can charge for free. Another issue with community charging is how to ensure that residents don’t hog the chargers.

Table 1: Submetering options where average driver drives 7,000 miles per year

Table 2: Submetering options where average driver drives 18,500 miles per year. IE: Half are rideshare drivers driving 30,000 miles per year and half drive 7,000 miles per year

As you can see from the above two tables, Options 1 and 2 could end up being quite costly from the Apartment/HOA viewpoint if the drivers drive a lot of miles per year or if the Monthly fee is not chosen right. Even for these scenarios, we’d recommend a simple submeter that someone in maintenance can read and keep track of to ensure the monthly fee is fair and covering most of the electricity costs. However, this wouldn’t allow any data on individual drivers (ie, to see if a rideshare driver is taking advantage of the system).

It’s a complicated topic. If you own or operate an Apartment complex or work with an HOA and would like help with your EV installation, please contact us!

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