Re: Is 1 charger for every 100 cars enough ?
For passenger cars the calculation is:
9,000 miles pa average, 30 million private vehicles.
Charger can dispense ~12 miles per hour of range
Each car therefore needs 1 mile per hour of usage (avg car spends 95% of time parked up). Let's assume this is primarily done overnight when the user parks up. So they need an average of 24 miles per day charging, but they will utilise the charger for the full time.
If they have a 150 mile range battery (winter worst case), they need to charge this up every 6 days, assume 5 days to give some buffer. And a charge every 5 days for 24 miles per day of charging requires 10 hours of charging - which is fine for an overnight charge.
So we need around 6 million EV chargers. However, about 50% of people can charge at home on their driveways, so the real figure is probably around 3 million, plus say 10% to account for visitors, high season and so on. Rapid chargers deployed appropriately could probably replace many of these chargers, rough calculation would be one 150kW rapid charger would replace 40 slow AC chargers, so a single 'EV station' with 8 rapid chargers in a town could compensate for a lack of 320 slower chargers.
It's definitely a long way off happening, with the UK government currently in a paralytic state where they assume the Free Market(TM) will deal with the problem.
For rapid chargers, the situation is better, because they make a lot more money for operators.