Plan smarter energy use with battery storage insights. Model tariffs, export credit, and demand charges. See yearly savings, payback, and lifetime value projections now.
| Scenario | Capacity | Solar charge | Grid charge | Peak/Off-peak | Export | Net Year‑1 Savings | Payback |
|---|---|---|---|---|---|---|---|
| Starter | 10 kWh | 6 kWh/day | 2 kWh/day | 0.30 / 0.15 | 0.08 | $1,200.00 | 6 yrs |
| Solar-heavy | 13.5 kWh | 9 kWh/day | 0 kWh/day | 0.32 / 0.14 | 0.07 | $1,650.00 | 7 yrs |
| TOU arbitrage | 7 kWh | 0 kWh/day | 6 kWh/day | 0.38 / 0.12 | 0.00 | $1,480.00 | 5 yrs |
Example rows are illustrative; your tariff and behavior drive results.
Degradation reduces the energy-savings portion each year: Year y uses (1 − Degradation)(y−1).
Battery storage savings are driven by the spread between high and low electricity prices, plus the value of avoiding exports. This calculator converts your daily charging plan into annual cash flows, then reports Year‑1 net savings, payback, NPV, and IRR so you can compare options consistently. For accuracy, match charging energy to usable capacity and cycles per day; the calculator caps daily charge if inputs exceed limits. Degradation reduces the energy‑savings portion each year using your annual percentage, while maintenance is treated as a fixed yearly cost. Run scenarios by adjusting rates, battery cost, and incentives to see how results shift across optimistic, expected, and conservative assumptions. Include replacement costs when warranties end and components age sooner.
Time‑of‑use (TOU) arbitrage occurs when the battery charges at an off‑peak rate and discharges during peak hours. The tool estimates TOU value as (delivered grid energy × peak rate) minus (grid charging energy × off‑peak rate). Round‑trip efficiency reduces delivered energy, so realistic efficiency inputs matter.
With solar, the battery can store excess generation that would otherwise be exported. The model values that shift as avoided peak purchases, minus the export credit you give up. If export credits are low, self‑consumption typically increases savings; if credits are high, the battery must also provide TOU or demand benefits to justify cost.
Commercial customers may also save through demand charge management. If enabled, annual demand savings equal demand charge ($/kW‑month) × expected peak kW reduction × 12. Because demand events are sporadic, use a conservative kW reduction and verify against interval data or sub‑metering before committing capital.
Financial metrics translate energy savings into investment decisions. Cash flows include upfront cost, incentives, yearly net savings, and optional replacement costs. NPV discounts each year at your chosen rate, rewarding earlier savings. Payback marks when cumulative cash flow turns positive. IRR is the rate where NPV equals zero and may not exist if cash flows never cross.
Peak and off‑peak rates, export credit, daily charging energy, and efficiency usually dominate. Costs and incentives determine payback, while discount rate and degradation shift NPV and IRR over the project life.
Storing solar energy means you export less. The calculator treats that lost export payment as an opportunity cost, so savings reflect the real trade‑off between exporting and self‑consuming later.
Set grid charge to zero and use only solar charge. The model will value savings mainly from avoided peak purchases minus the forgone export credit, adjusted by round‑trip efficiency and degradation.
Use interval data or a monitor to find typical monthly peaks, then choose a conservative kW reduction the battery can reliably shave. Demand peaks can be brief, so don’t assume the full inverter rating.
IRR requires cash flows to switch sign. If lifetime net cash flow stays negative, or the pattern crosses multiple times, a single IRR may not be defined, even though NPV still provides guidance.
Compare the year‑0 upfront cost with later annual net cash flows, then watch the cumulative line. A faster rise indicates quicker recovery, and dips may reflect replacement costs or lower savings from degradation.
Savings depend on tariffs, weather, household load shape, battery controls, and export rules. This estimate is for planning and comparison. For investment decisions, validate using actual interval data and a qualified professional.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.