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Electric Vehicle load management programs are increasingly important to utilities across the nation -- to avoid capacity/transmission charges, to increase nighttime load, or just to prepare for the future. However, not all load management options are created equal, both in the number and type of vehicles enrolled.


Sagewell has been running EV load management programs for our clients for over three years, and we've tried or researched nearly every load management option under the sun. We were one of the first organizations to do direct load control using commercially available residential smart chargers. We have tens of thousands of days of charging data from smart chargers and AMI meter data that demonstrate what works, and what doesn't.

Massachusetts has some of the best publicly available data about EV adoption, through the MOR-EV electric vehicle rebate, which has been active since 2014. The MOR-EV rebate database has records for over 14,000 vehicles (though the total EV adoption in the state may be twice that). We can compare the mix of vehicles statewide to the vehicles that have enrolled in our load management programs.

Looking at statewide data, the most commonly rebated vehicles are:

  • Tesla Model 3 (20.8% of vehicles)
  • Chevrolet Volt (12.7%)
  • Tesla Model S (11.2%)
  • Toyota Prius Prime (10.4%)
  • Chevrolet Bolt (9.0%).

These vehicles make up 64.1% of all rebated vehicles in the state, and the top 10 (Nissan Leaf, Tesla Model X, Honda Clarity, Ford Fusion) cover nearly 85%.

Compare this to vehicles enrolled in our programs that have a smart charger:

  • Chevrolet Bolt (31.9% of enrolled vehicles, 22.9 pp higher than the state as a whole)
  • Chevrolet Volt (13.8%, 1.2 pp higher)
  • BMW i3 (8.5%, 6.4 pp higher)
  • Nissan Leaf (8.5%, 2.5 pp higher)
  • Tesla Model 3 (7.4%, 13.3 pp lower than the state as a whole)

Notice that smart charger adoption for Tesla Model 3 is 13.3 percentage points lower than the state as a whole, and the Model S and X don't appear in the top 5 (or even top 10!). The Tesla Model S and X are underrepresented by 10.1 and 3.6 percentage points respectively. Teslas account for about 35% of the EVs on the road, but make up more than half of the EV charging load. Tesla owners are much more likely than other all-electric vehicle drivers to use either a 240 volt wall outlet, or a Tesla branded 'dumb' charger, therefore, they are use smart chargers at a significantly lower rate than other vehicles.

For comparison, let's look at vehicles enrolled in the Bring Your Own Charger (BYOC) program in Massachusetts (which also includes the majority of our EV drivers with smart chargers).

  • Tesla Model 3 (21.1% of vehicles, 0.3 pp higher than the state as a whole)
  • Chevrolet Bolt (14.1%, 5.0 pp higher)
  • Tesla Model S (13.3%, 2.1 pp higher)
  • Chevrolet Volt (10.2%, 2.5 pp lower)
  • Tesla Model X (6.3%, 1.5 pp higher)

The Chevrolet Volt and Prius Prime (4.6 pp lower than the state as a whole), with their smaller batteries and lower charging rates, are the most under-represented vehicles enrolled in the BYOC program. Because BYOC doesn't require added hardware and works with all brands of vehicles and chargers, the barriers for enrollment are very low.

What EV load management options is your utility considering? Every approach— Time-of-use rates, separate EV meters, smart chargers and BYOC— has benefits and drawbacks.




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