For each kwh you feed to the grid you get a credit for the value of that kWh during that time. Say off-peak is $.20 and peak is $.40 (this is an exaggeration but makes the math easy). You would need to feed 2 kWh to the grid during off peak to cover 1 kWh drawn from the grid during peak usage. On top of this there are non-by passable charges for every kWh drawn from the grid regardless of any credits on your account.
I see no reason why not do this in proper spot market way. Calculate it every 5 minutes, what you supply you get accounted for and what you use or that is withdraw you get accounted. At certain intervals these are matched and you pay the difference.
> I see no reason why not do this in proper spot market way.
The wholesale/spot electricity market is a scary place, as some people in Texas discovered last year [1]
Time of use pricing tranches are designed to insulate consumers from that sort of variability, while also incentivizing consumers to minimize consumption during peak demand times.
Time-of-use electricity pricing has been happening in California for a long time, but only now is it becoming mandatory (there are still many households out there on legacy flat-rate plans, although they are being moved).
Many parts of the country are just now introducing time-of-use pricing. As both the grid and loads become smarter and more resilient, we'll see consumer electricity rates reflect the underlying wholesale price variability even more, but probably never completely.
Those numbers are actually really close to reality for some of the electrical vehicle rates, which go down as low as $0.21 for off peak, around $0.40 for part-peak, and $0.53 for full peak. Other TOU rate plans only go as low as $0.31 during some seasons, and peak in the mid 40 cent range.
