Battery Value Without Solar
A battery without solar has one fewer value stream to draw on: no excess solar production to capture, just grid-charging at cheap rates and discharging at expensive ones, plus whatever outage protection you value separately.
At your inputs, a standalone battery, without solar has an NPV of -$10,070 over 10 years, with a discounted payback of no discounted payback within this horizon.
| Net cost after confirmed incentives | $12,000 |
|---|---|
| Annual savings | $250 |
| Net present value | -$10,070 |
Breakeven: No discounted payback occurs within the selected horizon.
- This uses planning estimates you entered, not a contractor quote or guaranteed savings.
- A positive NPV does not guarantee the actual outcome; it reflects your entered assumptions discounted at your chosen rate.
What this also tells you: A positive NPV means the option is worth more than its cost even after discounting future savings back to today; a negative NPV means the upfront cost outweighs what the savings are worth today.
This is a planning estimate based on your entries. It does not size equipment, determine electrical or building-code compliance, verify incentive eligibility, or replace a contractor quote or professional energy audit.
Why this decision comes up
Not every homeowner considering a battery has solar or plans to get it soon, and the standalone economic case deserves an honest look rather than an assumption that batteries only make sense paired with solar.
How this is calculated
This discounts the annual rate-arbitrage savings back to today's dollars over your ownership horizon, netted against the battery's cost, to produce an NPV and discounted payback.
A worked example
With the defaults ($12,000 net cost, $1,800/year grid-only cost dropping to $1,550/year, 10-year horizon, 5% discount rate), the annual savings is $250 and the NPV comes out negative at about $10,070, a clearly weaker case than the same battery paired with solar. This reflects the real gap between the two scenarios, not a flaw in the standalone case specifically.
Common mistakes
A common mistake is running this comparison with an optimistic rate-arbitrage assumption that does not match your actual utility rate plan. Confirm your time-of-use spread or demand-charge structure before trusting the result.
Limitations
This does not include outage protection value or a confirmed incentive unless you enter one, both of which can meaningfully change the standalone case.
Common questions
Is a battery ever worth it without solar?
It can be, particularly with a strong time-of-use rate spread, meaningful demand charges, a strong confirmed incentive, or high outage-protection value. Run your own numbers rather than assuming solar is required.
How much worse is the standalone case compared to pairing with solar?
Usually meaningfully worse, since a battery paired with solar can capture otherwise-exported production in addition to rate arbitrage. Compare both tools directly to see the gap with your own numbers.
Should I get solar first, then add a battery?
That is a common and often more economical sequencing, since it lets the battery capture solar export value on top of rate arbitrage. But it depends on your specific rate plan and roof suitability for solar.
Does having an EV charger change this standalone case?
It can. EV charging often shifts usage patterns and may unlock or strengthen time-of-use arbitrage value. If you have or plan to get a home charger, reflect that usage pattern in your annual savings estimate.
What if I get solar later, after buying a standalone battery?
You can typically add solar to an existing battery system later. At that point, re-run the with-solar value tool to see the improved economics of the combined system.