Performance guarantee shortfall calculator
Compare measured kWh with a guaranteed kWh after a weather adjustment, year by year, under an annual test and a cumulative test.
A teaching aid, not a contract calculation. The presets are invented (700,000 kWh guarantee, 0.09 USD per kWh). Your contract's wording decides the method, the exclusions and the payment. Have a lawyer review any guarantee clause.
| Year | Raw margin (kWh) | Adjusted margin (kWh) | Shortfall (kWh) |
|---|
| Test | Result |
|---|---|
| Raw margin, all years, no adjustment (kWh) | - |
| Annual test: shortfall years summed, no carry-forward (kWh) | - |
| Annual test: payment (USD) | - |
| Cumulative test (sum of yearly margins): net margin (kWh) | - |
| Cumulative test (sum of yearly margins): payment (USD) | - |
| Cumulative test, whole-period adjustment: net margin (kWh) | - |
| Cumulative test, whole-period adjustment: payment (USD) | - |
Margin is adjusted kWh minus the guarantee, so a negative margin is a shortfall. With the first two methods the pass or fail verdict is the same, but the kWh shortfall differs by the factor X/Y, so the payment differs. The cumulative test adds yearly margins; the whole-period line adjusts the summed totals once, as a contract that sums insolation over the period would. A cap, if entered, limits each payment line.