Batteries are primarily used for intra-day time shifting, not weekly. I agree that going completely off grid costs substantially more than being able to use your own generated power for 80-90% of usage. That’s why I focused on the case where home owners remain grid-connected in my top-level comment:
With smart meters and cheaper home battery systems the incentives starts to shift toward wealthier solar enthusiasts buying batteries and selling excess power to the grid at peak times (or consuming it themselves), lowering peak demand at no additional capital or maintenance cost to the grid operators.
The only mention I made regarding completely off-grid power systems was about the counterfactual scenario of $150/kW-hr battery cost, which I have not assumed anywhere else. I didn’t say that it would be marginally cost effective to go completely off grid with such battery prices, just that it would be substantially more cost-effective than buying all my power from the grid. The middle option of 80-90% reduced but not completely eliminated grid use is still cheaper than either of the two extremes, and likely to remain so for any feasible home energy storage system.
That’s what I was referring to regarding $700 kW/hr. At $1000/kW-hr it’s (just barely) not worth even buying batteries to shift energy from daytime generation to night consumption, while at $700/kW-hr it definitely is worthwhile. Do you need the calculation for that?
At $1000/kW-hr it’s (just barely) not worth even buying batteries to shift energy from daytime generation to night consumption, while at $700/kW-hr it definitely is worthwhile.
Doesn’t this depend heavily on local utility rates, and so any discussion of crossover points should include rates? Ex: I’m at $0.33/kWh while a friend in TX is at half that.
Yes, it definitely does depend upon local conditions. For example if your grid operator uses net metering (and is reliable) then it is not worthwhile at any positive price. This statement was in regard to my disputed upstream comment “Even now at $1000/kW-hr retail it’s almost cost-effective here [...]”.
It would be helpful to see a calculation with your rates, the installed cost of batteries, cost of the space taken up, losses in the batteries and convertor, any cost of maintenance, lifetime of batteries, and cost (or benefit) of disposal.
Batteries are primarily used for intra-day time shifting, not weekly. I agree that going completely off grid costs substantially more than being able to use your own generated power for 80-90% of usage. That’s why I focused on the case where home owners remain grid-connected in my top-level comment:
The only mention I made regarding completely off-grid power systems was about the counterfactual scenario of $150/kW-hr battery cost, which I have not assumed anywhere else. I didn’t say that it would be marginally cost effective to go completely off grid with such battery prices, just that it would be substantially more cost-effective than buying all my power from the grid. The middle option of 80-90% reduced but not completely eliminated grid use is still cheaper than either of the two extremes, and likely to remain so for any feasible home energy storage system.
That’s what I was referring to regarding $700 kW/hr. At $1000/kW-hr it’s (just barely) not worth even buying batteries to shift energy from daytime generation to night consumption, while at $700/kW-hr it definitely is worthwhile. Do you need the calculation for that?
Doesn’t this depend heavily on local utility rates, and so any discussion of crossover points should include rates? Ex: I’m at $0.33/kWh while a friend in TX is at half that.
Yes, it definitely does depend upon local conditions. For example if your grid operator uses net metering (and is reliable) then it is not worthwhile at any positive price. This statement was in regard to my disputed upstream comment “Even now at $1000/kW-hr retail it’s almost cost-effective here [...]”.
It would be helpful to see a calculation with your rates, the installed cost of batteries, cost of the space taken up, losses in the batteries and convertor, any cost of maintenance, lifetime of batteries, and cost (or benefit) of disposal.