Oh man, they are coming for our tandems too!? My area is still under NEC 2020 by ordinance, which is still more recent than a lot of surrounding counties. It’s still recent enough to need GFCI on dual-pole breakers going to outlets, which was a real pain in terms of availability and cost.
There is a lot of addressable market that can add chargers inexpensively. But I get that doesn’t mean much to anyone in a 70 year old home with a full panel, all electric appliances, and 2 AWG cable buried in the yard.
To try to save some money, make sure you really need the 40 amp charger circuit and make sure your panel really needs the upgrade. I don’t want to imply that you are getting into $6k of work without thinking very hard, but here’s some thoughts and observations, just in case your electrician didn’t suggest all this.
Tandem breakers can be used to move two single-pole circuits into one breaker slot. Doing this with four circuits can free up space for a double. Also check on how much peak load you are actually pulling, then figure on how many reactive starting loads are realistically going to happen at once (like AC coming on). I have the 40 amp charger circuit, a 50 amp hot tub circuit, a dozen servers pulling ~7 amps all day, and two air conditioners (main 40 amp and garage mini-split 15 amp). My peak 1 minute load is like 59 amps while charging the car. All that said, if you have electric baseboard heat in your home that can be a lot tighter of a squeeze.
I have had the EV for two years and I also find that a 240v 15 amp charger circuit, 12 amp max charge would have been perfectly fine for me. That would allow recovery of about 60 miles overnight, or ~90 miles in a typical commute-to-commute time-span of 14 hours. That’s with a big chonky Nissan Ariya, the Bolt will do better.
Quick math shows I am quite a bit more efficient than a Nissan Juke traveling 150 miles at 19mph. About 50kcal/pound for the car and 8kcal/pound for me+bike to travel the distance.