Looking at the price chart again I notice that self consumption price arbitrage provides much higher price spread versus export only. Storing solar that would otherwise cost $-0.025 to export and then self consuming during 4 - 8pm would net $0.445 profit. That would take DIY battery payback down to 339 cycles.
Precisely. With where rates will be headed under NEM 3, the best strategy is to avoid / minimize export while offsetting consumption during the day (which means capturing excess energy that would otherwise get exported into a house battery) and then to use that stored energy to offset consumption overnight.
You only want to allow energy to export in the afternoon once the house battery is charged and it would otherwise be wasted.
Grid-tied ESS and a larger battery allows you to export any excess energy between 7-9pm when the grid pays the most but it’s really not clear whether there is any actual payoff for that extra effort and cost.
The rules for how compensation for overgeneration at annual true-up under NEM 3 are not yet clear but it is unlikely they will allow you to earn more than Net Surplus Compensation Rates for any annual overgeneration (as is the case under NEM 1.0 and NEM 2.0).
What throws things off under NEM 3 is that
all NEM 3 installs should significantly overgenerate (since they can be sized to produce 150% of annual consumption in kWh).
So if we assume you perform unnatural acts to export all of your overgeneration from 7-9pm at credit rates close to near-peak, that annual Overgeneration credit of ~50% x $0.32 is unlikely to be compensated at more than 1/4 that level (~50% x NSCR which is currently $0.08).
If you consume an increased amount of peak-period energy during winter months when solar generation wanes (for example from electrical heating), it’ll no-doubt pay off to invest in a more expensive system / battery to export only during 7-9pm over summer months.
But for those with relatively flat consumption through winter months, just avoiding overnight consumption with a minimum-sized battery sized to capture that amount of energy is likely the quickest path to break-even…
Will need to wait for the first NEM 3 true-ups a ~year from now to understand how it all works…