The Throughput Problem: Recharging Electric Cars Requires the Patience of Job, And now you have to wait in line for a 30-minute long partial refueling!
- Dec 7, 2019 4:46 am GMT
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CAR GUY - The Throughput Problem: Recharging Electric Cars Requires the Patience of Job, And now you have to wait in line for a 30-minute long partial refueling! By Eric Peters, December 5, 2019, 12:04 AM
There was an interesting story over the holiday about electric cars piled up at “fast” chargers … waiting in line for other EVs to finish “fast” charging. This brings up the problem of throughput — another of many EV problems not being reported by the general press or the car press (the latter being inexcusable).
It is a function of the EV’s much longer recharge time versus a non-electric car’s time to refuel. Even in a best-case scenario — at what are hilariously (and depressingly) styled “fast” chargers — an EV takes at least five times as long (about 30 minutes) to recover a partial charge as it takes to fully refuel a non-electric car.
Consider what this means in terms of how many electric cars can recharge in one hour at a limited number of “pumps.”
A gas station that has, say, six gas pumps can refuel six cars in about five minutes, but for the sake of discussion call it 10 minutes each — to take into account people leaving their car at the pump for a couple of minutes longer than it takes to fill up to go inside to buy a soda, et cetera. The station’s throughput at that rate is six cars every 10 minutes. Twelve cars in 20; 36 cars in an hour.
But six EV “fast” chargers can only charge six cars — partially — in 30 minutes. In the same hour that it takes to refuel 36 cars, only 12 EVs are partially recharged — this being necessary at a “fast” charger to avoid damaging the very expensive battery and shortening its already short useful life. The EV can only accept about 80 percent “fast” charge; the remainder has to be charged slowly. Well, even more slowly. The full charge takes an hour-plus — but let’s leave that problem aside for purposes of this discussion.
The EV leaves the “fast” charger with 80-percent charge. Which means it’ll have to be recharged again, sooner. That’s the best-case scenario, remember.
The only way to mitigate this — in terms of the number of EVs that can charge at the same time — would be to build at least three times as many “fast” chargers as there are gas pumps. But where will the money come from? And where will the space come from?
Six pumps fit easily on a small concrete pad. But it would take the equivalent of three times as much space to match the gas station’s throughput capacity with EV “fast” chargers. This means a tripling of real estate and construction costs to the owner of the “fast” charge” station. More waste, too — of concrete and steel and all the other material that goes into building a gas — or EV — station.
Would the local power distribution system be ready for that?
Would the grid be ready for that? Easier said than done…
Would the renewable energy converters be ready for that?