If people used their rooftop solar to charge their electric cars, a big contribution. Once again, my pitch was that usage so close to generation decreases line loss, plus gives residents more control over greedy utilities (who btw could care less about regional HVDC). I guess the 40% number would be "of current electricity used" not "overall energy use", of which (as you say) electricity is only a portion. Electric heat pumps being heavily pitched, but where will all that electricity come from? I'd say in CA, rainwater cisterns/water source heat pumps a better fit, and/or circulating hot water solar for hot water/heat. I wrote another (not so popular) article once saying that mass transit was becoming kind of a dog (sadly).

https://scottvern.medium.com/r-i-p-rail-mass-transit-fb0db319bda9

A UCB transportation engineer friend believes all domestic transportation is going towards smart electric cars and air travel. If so, home charged electric and hydrogen fuel cell airplanes the future? For industry, military, everything else a hydrogen/biogas network, compressed hydrogen/fuel cells, along w your Next Gen Nuclear?