Availability calculator
Technical and contractual availability, time-based and energy-weighted, for one period of identical days.
A teaching aid, not a contract calculation. The preset is invented (four equal inverters, 30 identical days, invented irradiance profile and 98% guarantee). Real days differ, and your contract's definition decides. Events must not overlap in time.
| Reading | Availability | Against guarantee |
|---|---|---|
| Technical, time-based (every outage counts) | - | - |
| Technical, energy-weighted (every outage counts) | - | - |
| Contractual, time-based (excluded events removed) | - | - |
| Contractual, energy-weighted (excluded events removed) | - | - |
| Energy-based, all losses counted (no exclusions, curtailment included) | - | - |
| Whole-plant outages only (plant is available if any inverter runs) | - | - |
| Contractual, time-based, excluded events counted as available | - | - |
| Contractual, energy-weighted, excluded events counted as available | - | - |
| Window plant-hours (hours above the cut-off, all days) | - | |
| Contractor plant-hours down, and the most the guarantee allows | - | - |
Method: plant-hours down divided by plant-hours in the window. Energy weights use irradiance as a proxy for lost energy, so they ignore temperature and inverter clipping. Curtailment is not downtime (the plant is able to produce), so it only enters the energy-based reading with no exclusions.