Around 2 p.m. on a clear day, most rooftop solar arrays are making more electricity than the house can use. That surplus has to go somewhere—either onto the grid for a credit, or into a battery for later. The choice sounds simple, but the math has shifted a lot in the past few years, and the old default of "just sell it all back" no longer holds in most of the country.
Then utilities started rewriting the rules. California's NEM 3.0, which took effect in 2023, cut the value of exported solar by roughly 75% compared to the prior structure, according to analysis from the California Public Utilities Commission's own filings. Other states have followed with lower "avoided cost" export rates instead of retail credits. When your utility pays you 4 cents for a kilowatt-hour it turns around and sells for 30, exporting stops looking like a good trade.
That gap—between what you're paid to export and what you'd pay to buy power back at night—is the whole reason storage now matters.
The economics track with how utilities are pricing time. The U.S. Energy Information Administration reports that residential time-of-use plans increasingly push the highest rates into the 4–9 p.m. window—exactly when a battery discharges. A stackable LFP setup, like Sigen's BAT modules that scale to roughly 54 kWh per stack, lets a household size storage to its actual evening load rather than a one-size-fits-all box.
Storage also buys resilience. During an outage, exported solar does nothing for you—grid-tied inverters shut off for safety. A battery paired with backup hardware such as the Sigen LoadHub, which switches over in about a millisecond, keeps the fridge and the router running whether or not the utility is paying much for your daytime surplus.
The trend, though, points one direction. NREL research on distributed energy has flagged that as more homes go solar, utilities keep trimming export compensation to reflect the falling midday value of power. Batteries are the hedge against that slide.
For anyone weighing the trade-off, it helps to model both paths against real rate data before committing—tools that let you compare storage versus export scenarios for your specific tariff will show the crossover point faster than any rule of thumb. That's the honest starting point, whichever way your numbers land.
外链信息：
What changed with net metering
For a long time, the deal was clean: send a kilowatt-hour to the grid, get a full retail kilowatt-hour credit back. That arrangement, called net metering, made batteries feel optional. Export was as good as banking the power.Then utilities started rewriting the rules. California's NEM 3.0, which took effect in 2023, cut the value of exported solar by roughly 75% compared to the prior structure, according to analysis from the California Public Utilities Commission's own filings. Other states have followed with lower "avoided cost" export rates instead of retail credits. When your utility pays you 4 cents for a kilowatt-hour it turns around and sells for 30, exporting stops looking like a good trade.
That gap—between what you're paid to export and what you'd pay to buy power back at night—is the whole reason storage now matters.
The case for storing it
If you use a home solar battery storage system, that midday surplus gets held until evening, when rates peak and the sun is gone. Instead of selling low and buying high, you're essentially paying yourself retail rate for your own electrons.The economics track with how utilities are pricing time. The U.S. Energy Information Administration reports that residential time-of-use plans increasingly push the highest rates into the 4–9 p.m. window—exactly when a battery discharges. A stackable LFP setup, like Sigen's BAT modules that scale to roughly 54 kWh per stack, lets a household size storage to its actual evening load rather than a one-size-fits-all box.
Storage also buys resilience. During an outage, exported solar does nothing for you—grid-tied inverters shut off for safety. A battery paired with backup hardware such as the Sigen LoadHub, which switches over in about a millisecond, keeps the fridge and the router running whether or not the utility is paying much for your daytime surplus.
When selling still makes sense
Storing isn't automatically the winner. A few situations still favor export:- Full retail net metering is still in place. If your state grandfathered you in or hasn't changed the rules, exported power holds its value, and a battery's payback stretches out.
- Low overnight usage. If almost nobody's home in the evening and your loads are tiny, there's little to discharge into.
- No demand charges or steep time-of-use spread. Flat-rate customers capture less benefit from shifting when they draw power.
How to decide for your own roof
Two numbers settle most of it: your export rate and your evening buy-back rate. If the gap between them is wide, storing wins. If they're close, exporting is fine and cheaper upfront.The trend, though, points one direction. NREL research on distributed energy has flagged that as more homes go solar, utilities keep trimming export compensation to reflect the falling midday value of power. Batteries are the hedge against that slide.
For anyone weighing the trade-off, it helps to model both paths against real rate data before committing—tools that let you compare storage versus export scenarios for your specific tariff will show the crossover point faster than any rule of thumb. That's the honest starting point, whichever way your numbers land.
外链信息：
- https://www.sigenergy.com/en/solution-aggregation — anchor: home solar battery storage system
- https://www.sigenergy.com/en/solution-aggregation — anchor: compare storage versus export scenarios for your specific tariff
