Under classic net metering, the grid acts like a free battery: every kWh your panels export earns a credit worth about what you pay for electricity. As more utilities move away from that, the question changes. If an exported kWh earns only a fraction of the retail price, storing it for later starts to make financial sense. Here is how to tell whether it makes enough sense for you.
Quick answer
A battery is worth much more without full net metering, but it rarely pays for itself on bill savings alone. Each kWh you store instead of exporting saves roughly your retail rate minus the export credit you give up. With a typical 13.5 kWh battery at about $15,647[src] and no federal tax credit, simple payback ranges from about 15 years at California-level rates to 41 years at the U.S. average rate (if you shift 10 kWh a day). High rates, time-of-use pricing, utility programs and backup value are what make it worthwhile.
Key takeaways
- Without full net metering, exported solar earns less than the electricity you buy back later.
- A battery captures that gap: value per kWh ≈ retail rate × efficiency − export credit.
- The higher your electricity rate and the lower your export credit, the faster the payback.
- With no federal credit, bill savings alone rarely repay a battery within its warranty, except at very high rates.
- Utility programs and outage protection can tip the decision.
Read more in our home battery guides.
What changes when net metering goes away
With full net metering, a kWh you export at noon offsets a kWh you buy at night at the same price. A battery adds little to your savings, because the grid already “stores” your surplus for free.
With net billing or other successor tariffs, exports are credited below retail. California is the best-known example. Its Net Billing Tariff, which applies to customers who submitted an interconnection application on or after April 15, 2023, credits exports based on their value to the grid: the utility’s avoided cost of buying clean electricity elsewhere, according to the California Public Utilities Commission. The CPUC designed it to encourage batteries that store midday solar for use or export in the late afternoon and evening, when the grid is most stressed. It notes that greenhouse gas emissions are highest between 4 and 9 p.m.
Export credits under these tariffs change by hour, season and utility, so check your own utility’s published export rates.
The math: how much a battery saves
For every kWh of solar you store instead of exporting:
Value ≈ your retail rate × battery efficiency − the export credit you give up
We use 89%[src] efficiency (Tesla’s rating for Powerwall 3). Multiply the value per kWh by the kWh you shift per day and by 365 to get yearly savings. Then compare that with the battery’s price: about $15,647[src] for a typical 13.5 kWh system before incentives, with 0%[src] federal tax credit for homeowner batteries placed in service after 2025.
| Rate scenario | Retail rate | Export credit (assumed) | Yearly savings | Simple payback |
|---|---|---|---|---|
| California average rate, no export credit | 32¢ | 0¢ | $1,039 | 15 years |
| California average rate, low export credit | 32¢ | 5¢ | $856 | 18 years |
| California average rate, higher export credit | 32¢ | 10¢ | $674 | 23 years |
| U.S. average rate, no export credit | 17.2¢ | 0¢ | $560 | 28 years |
| U.S. average rate, low export credit | 17.2¢ | 5¢ | $377 | 41 years |
Two things stand out. First, the gap between retail and export prices drives everything: at California-level rates, the battery earns several times more per kWh than at the national average. Second, even in the best case shown, simple payback is close to or beyond the length of a typical battery warranty (Powerwall 3 is warrantied for 10 years[src]). That is why bill savings alone rarely justify a battery.
What can make a battery pay off faster
- Time-of-use rates. If your evening rate is far above your average rate, each stored kWh is worth more than the averages above suggest. Check your utility’s peak price.
- Utility programs that pay you. In Massachusetts, ConnectedSolutions pays $275/kW[src] of average summer event output, and National Grid reports an average of about $1,200[src] a year. Similar “virtual power plant” programs exist in other states.
- State incentives. Some states and utilities offer upfront rebates; see our battery cost guide for examples.
- Backup power. Outage protection has no line on your bill, but for many households it is the main reason to buy. If you would otherwise buy a generator, count that avoided cost.
A battery without net metering
Pros
- Captures the gap between retail rates and low export credits
- More valuable on time-of-use plans
- Provides backup power during outages
- Can earn money in utility programs
Cons
- High upfront cost with no federal credit
- Payback often near or beyond the warranty period at average rates
- Savings depend on tariffs that can change
When a battery is (and isn’t) worth it
Likely worth it if your electricity is expensive (especially in the evening), your export credit is low, you can join a program that pays for battery use, or you value backup power.
Probably not worth it on savings alone if you still have full retail net metering, your electricity rates are near or below the national average, or you would not use backup power.
To size a battery for your evenings or for backup, use the battery size calculator. To see what solar alone saves, try the solar savings calculator.
