Savings and payback

Savings with battery vs without battery

See how much more you'd save each year by storing excess solar for later use, instead of exporting it to the grid at a lower credit rate.

For planning purposes only, not financial or tax advice; confirm figures with a licensed installer or tax professional before making a purchase decision.

Your numbers

1 Production and rates
Use the production figure from the solar savings calculator if needed.
Also called avoided-cost or net metering credit rate. Check your utility's net metering policy.
Portion of solar production used directly on-site, without storage.
2 Battery capture
Portion of the otherwise-exported power the battery shifts to self-use instead.

How it works

Three steps to your battery comparison

Step 1

Enter your production and both rates

You'll need your retail rate and your utility's export credit rate, which is often lower. Check your net metering policy for the export figure, or use the solar savings calculator to estimate production first.

Step 2

Estimate self-consumption without a battery

This is the share of solar production you use directly as it's generated, before any is exported. Most homes without storage self-consume 30 to 50%.

Step 3

Add expected battery capture

Your installer can estimate how much excess your specific battery size will capture. The tool then compares total savings both ways. If your bill has a demand charge, pair this with the peak shaving savings estimator too.

Understanding the battery savings gap

Why the numbers come out the way they do

In one example, a battery shifting 30% of otherwise-exported power to self-use added about $171 a year, going from $949 without a battery to $1,120 with one. The gap exists because exported power only earns a $0.06 per kWh credit in this example, while self-consumed power offsets electricity at the full $0.16 retail rate, a real difference of $0.10 for every kWh the battery redirects. Utility rates drive the whole savings calculation, and the US Energy Information Administration's electricity data track them state by state.

Self-consumption versus export credit

Without storage, any solar production beyond what your home uses in that moment gets exported to the grid, earning whatever your utility's net metering or avoided-cost rate happens to be. That rate is frequently well below retail. A battery closes that gap by holding excess production until you can use it yourself, later in the day or overnight. The bill offset percentage calculator can help estimate your self-consumption share if you're not sure where to start. The US Energy Information Administration's solar explainer covers how solar generation works and where it fits in the wider grid.

Battery capture has limits

A battery doesn't capture 100% of your excess production, since capacity is finite and usage patterns vary day to day. Larger batteries capture more, but returns diminish once a battery covers most evening usage. This is a separate question from peak demand charges, which the peak shaving savings estimator covers specifically, and from time-of-day pricing, which the time of use rate savings calculator handles. The off grid solar kit cost comparison tool covers off-grid sizing, which this estimate does not try to do.

Is the extra savings worth the battery cost

Savings alone often make for a longer payback on a battery than on solar panels, since the added dollar benefit is smaller relative to the added cost. Many buyers add a battery primarily for backup power during outages, with these savings as a secondary benefit rather than the main financial case. If an EV is in your plans, the ev charging cost with solar vs grid comparison adds its charging load to the sizing math.

Questions

Frequently asked

It depends on your export credit rate and how much excess production the battery captures. In one example, a battery shifting 30% of otherwise-exported power to self-use added about $171 a year in savings, going from $949 to $1,120 annually.

Self-consumed solar offsets electricity you'd otherwise buy at your full retail rate. Exported solar earns a net metering credit instead, which many utilities set below retail, an avoided-cost rate around $0.06 per kWh is common versus $0.16 or more at retail.

No, battery capacity is limited, so it typically captures a portion of your excess production rather than all of it. A larger battery captures more, but there's a point of diminishing returns once it covers most evening usage. Your installer can model expected capture based on your usage pattern and battery size.

For pure savings, batteries often have a longer payback than solar panels alone, since the added savings are smaller relative to the added cost. Many buyers add batteries primarily for backup power during outages, with savings as a secondary benefit.

Related tools

Keep exploring rate structures

Peak shaving savings estimator Time of use rate savings Bill offset percentage calculator Solar savings by utility rate Savings with EV charging included Flat vs tiered rate savings Savings for high usage homes All savings and payback tools