Battery Inefficiency Cost Calculator
Quantify the financial drag from battery inefficiency before bidding into markets or structuring tolling agreements. Provide the megawatt-hours required to charge the asset and the measured round-trip efficiency. Optionally add the energy price you expect to capture. The tool reports delivered energy, energy lost to inefficiency, and the dollar value burned on every cycle.
Model assumes a single charging-discharging cycle with constant efficiency. Validate against your dispatch profile and degradation studies before committing capital.
Examples
- 4.5 MWh charge, 88% efficiency, $60/MWh energy ⇒ Deliverable energy: 3.96 MWh • Energy lost: 0.54 MWh (12.00%) • Value lost each cycle: $32.40
- 2.8 MWh charge, 92% efficiency, $85/MWh energy ⇒ Deliverable energy: 2.58 MWh • Energy lost: 0.22 MWh (8.00%) • Value lost each cycle: $19.04
FAQ
How should I estimate the round-trip efficiency?
Use metered charge and discharge data over a representative cycle that includes auxiliary loads. Many operators track both DC and AC efficiency—model the AC value for commercial impacts.
What if the efficiency improves after upgrades?
Update the efficiency input to see how firmware or inverter upgrades change the per-cycle loss. Pair the savings with upgrade costs to evaluate ROI.
Can I include demand-charge savings instead of an energy price?
Yes. Convert demand-charge reductions into an equivalent $/MWh value so the calculator reflects the opportunity cost of wasted energy during peak events.
Additional Information
- Losses represent heat, conversion, and auxiliary consumption that prevent every charged MWh from discharging to the grid.
- Energy value can be a wholesale market price, a tolling arrangement rate, or an internal transfer price for behind-the-meter assets.
- Multiply the per-cycle loss by expected annual cycles to budget yearly inefficiency costs for revenue models or O&M reserves.