Energy Storage Cost

Free Energy Storage Cost calculator with clear step-by-step results.

About Energy Storage Cost

Storage is not judged on its purchase price but on what each stored kilowatt-hour ends up costing. Divide the installed cost by the energy the battery will actually deliver over its life — capacity × cycle life × round-trip efficiency — and you get the levelised cost of storage. Efficiency matters twice over: energy lost on the round trip never reaches the load, so a 90% system delivers only 90% of its nameplate throughput. The result is the figure to compare against your tariff spread.

Formulas

Lifetime throughput

Throughput = usable capacity × cycle life × round-trip efficiency

Levelised cost

LCOS = installed system cost ÷ lifetime throughput

Worked example

With the default values below, Energy Storage Cost returns Levelised Cost of Storage of $0.1667. Change any input above and every figure here is recalculated in your browser.

Inputs used

Usable capacityminimum 0.1 kWh: 13.5 kWh
Installed cost per kWh of capacityminimum 0 $: 900 $
Rated cycle lifeminimum 1 cycles: 6,000 cycles
Round-trip efficiencyaccepts 1–100 %: 90 %
Cycles per yearminimum 1: 300

Results

Levelised Cost of Storage: $0.1667
Installed System Cost: $12,150.00
Cost per Full Cycle: $2.025
Expected Service Life: 20.0 years

Step by step

1Values used
2Lifetime throughput
3Levelised cost
4Levelised Cost of Storage= $0.1667/kWh
5Installed System Cost= $12,150.00
6Cost per Full Cycle= $2.025
7Expected Service Life= 20.0 years

Assumptions and limits

The result is derived only from the 5 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation or tax into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Cycle life is a warranty figure measured under specified conditions and degrades faster with heat, high charge rates and deep discharge. Battery installation is regulated work — use a qualified installer and follow local electrical codes.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Cycle life is a warranty figure measured under specified conditions and degrades faster with heat, high charge rates and deep discharge. Battery installation is regulated work — use a qualified installer and follow local electrical codes.

Frequently Asked Questions

When does storage pay for itself?

When the levelised cost per kWh is below the difference between your import and export or peak and off-peak prices. If storage costs $0.12/kWh and your peak-to-off-peak spread is $0.20, arbitrage is viable before considering backup value.

Why use usable rather than nominal capacity?

Batteries reserve a depth-of-discharge margin to protect cycle life, so nominal capacity overstates what you can actually cycle. Manufacturers quote both — use the usable figure.

Should the cost include installation?

Yes. Inverter, wiring, enclosure, permitting and labour are often 30-50% of a residential system, and excluding them makes the levelised cost look far better than it is.