Re: Industry not thinking things through - whatever next?
Let's say a medium-sized petrol filling station handles 1,000 cars a day - 80% of them between 0700-1900. Recharging all these 40kWh batteries in a day requires a 2MW supply. If it takes an hour to recharge each battery (as it does on a Tesla 120kW super-charger) you're going to fall behind the flow of cars with the aim of catching up overnight (when electricity's cheaper), so you'll need a good few hundred batteries in reserve to last the peak period. You can reduce the problem by charging faster (though I'm not sure how practical that is), but then your power supply requirements increase, and you can't make use of off-peak electricity. And this is assuming the very best (most expensive) technology available - most cars take much longer than a Tesla to recharge.
Thanks for those figures. Those are something which cab be verified and discussed.
It's not rocket science, is it?
No, it's escrow analysis, which is, indeed much simpler.
A simple escrow analysis of these numbers can tell us exactly how many batteries a station will
need in order to meet demand. Since you've given no more detailed picture of the demand curve, we'll assume for this discussion that it is uniform between 0700 and 1900 (high demand ~= 66.67 cars per hour), and between 1900 and 0700 (low demand ~=16.67 cars per hour). Further if you can recharge 1000 per day, you can recharge ~41.67 batteries per hour. Finally, let's assume you want a reserve of 10% (100 fully charged batteries) to deal with a sudden rush (in the case of such a rush, those reserve batteries will be replaced/recharged by an external service provider.) This is all we need for the escrow analysis.
By my calculation, the charging station only needs to store 442 batteries to supply the needs of the 1000 cars they service daily.
If the batteries took two hours to charge, the station would need to have 1171 batteries on-hand.