haha need to do the math...this is very general fag packet maths ofc
assumptions:
all ICE cars need to go to a station to fill up, an ICE car can fill up 0-full tank in about 5mins
not all EVs need to go to a rapid charger to fill up, it takes 30 mins to "fill" 60% of the battery (20-80)
an EV has shorter range...assume half the usable range of an ICE if babying the battery (80-20)
so, for the same range, an EV will need to go to a charger twice vs once for an ICE filling up to full each time
say 100,000 cars for the same distance
ICE = full tank -> drive -> fill -> drive
EV = 80 -> drive -> fill -> drive -> fill -> drive
so, if there were 100% ICE cars vs 100% EVs
ICE = total 500,000 minutes spent at the pumps (100k x 5 x 1)
EV, taking your 20% home charging = 80,000 needing to use a rapid charger
= total 4,800,000 minutes spent at a charger (80k x 30 x 2)
fag packet maths says will need about 10x more EV chargers than petrol pumps to avoid larger queues
the reality is probably a lot more nuanced though