Solar + Battery vs. Solar Only in South Carolina
Does adding battery storage improve your solar ROI? Analysis of TOU arbitrage value, net metering export losses, and backup power economics.
Adding a 13.5 kWh battery to a solar system in South Carolina changes the economics in three ways: it enables time-of-use (TOU) arbitrage, reduces export losses under unfavorable net metering policies, and provides backup power during outages.
The solar system alone produces a 25-year NPV of $10,528. Whether a battery adds to this depends entirely on your utility's rate structure. Most utilities in South Carolina use flat rate structures, which limits TOU arbitrage value.
Battery Economics: Duke Energy South Carolina
For Duke Energy South Carolina customers, battery storage has marginal economics with a 25-year NPV of -$11,382. The limited peak/off-peak spread means TOU arbitrage alone doesn't justify the cost. Backup power value and future grid services programs could improve the case.
Combined System Value
| Configuration | Net Cost | 25-Year NPV |
|---|---|---|
| Solar only (7 kW) | $9,730 | $10,528 |
| Battery only (13.5 kWh) | $8,400 | -$11,382 |
| Solar + Battery | $18,130 | -$854 |
Frequently Asked Questions
Is solar + battery worth it in South Carolina?
What incentives are available for solar + battery in South Carolina?
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