[SuoDuanDao]

I don't have the numbers with me, but I've seen convincing discussions that it can work with some caveats. The main issue being that spot prices are extremely volatile, so it's possible for a player at the utility space to get very high prices for electricity for very short times. But daytime-pricing schemes, while they follow the general trends of this volatility, insulate the consumer from the worst of this volatility enough that simply arbitraging the difference probably won't pay for the wear on a Tesla. But a fleet of Teslas paying the same rates as the utilities could make it a profitable enterprise.

Reading between the lines of Tesla investor meetings it sounds as though they have the software but haven't implemented it because it would hurt their brand as a luxury good.