Something is underperforming and there is a document that appears to cover it. Most claims that fail do so on evidence and procedure rather than on the substance.
Operational performance depends on both equipment and repeatable human routines; for a separate workplace-management perspective, see books about time management.
Reviewed August 9, 2026. Terms and remedies vary by contract and jurisdiction; this is not legal advice.
Establish which document applies
Three instruments, three counterparties.
For additional context on photovoltaic operation, maintenance and sector developments, consult Australian Government Energy.
Module product warranty — the manufacturer. Covers defects: a cracked module, a delaminated one, a manufacturing fault.
Module performance warranty — also the manufacturer. Covers output falling below a published curve at specified years.
Installer performance guarantee — the company that built it. Covers the plant as a system, usually for a shorter period, and usually against a figure derived from P90.
Inverter warranty — the inverter manufacturer, separately again.
Approaching the wrong party wastes weeks and the deadline continues running.
What evidence a claim needs
A baseline. What the plant produced when it was healthy. This is why the year-one record matters — without it, "it used to be better" is an assertion.
Irradiance-corrected performance. Performance ratio over time, not raw production, because the counterparty will otherwise attribute the shortfall to weather and they will frequently be right.
Evidence the obligations were met. Cleaning at the stated frequency, maintenance performed, monitoring maintained. Unmet obligations are the commonest reason a claim fails, and they fail it regardless of the merits.
Documentation of the fault — thermographic images, string-level data, photographs, serial numbers.
And the original documents. The guarantee, the yield report, the commissioning record.
The order to do things
Establish the shortfall is real before notifying anybody. Actual irradiance, performance ratio, string data.
Check the deadline. Many instruments require notification within a period of discovery, and the clock starts earlier than people assume.
Notify in writing, within the deadline, even if the investigation is incomplete. A late claim with good evidence loses to a timely one with partial evidence.
Then gather the rest.
And keep the plant running unless safety requires otherwise — a shut-down plant produces no further evidence and complicates the measurement.
What weakens a claim
Modifications by others. The single most common voiding condition.
Gaps in the maintenance record, even where maintenance happened — undocumented is unproven.
A monitoring subscription that lapsed, where the instrument required monitoring.
And a delay between discovery and notification, which invites the argument that the loss was allowed to accumulate.
When the answer is no
Ask on what basis, in writing. A refusal citing a specific clause is checkable; one citing general reasonableness is a negotiating position.
Check whether an independent assessment would change it. For a substantial claim, a third-party measurement report can move a refusal, and it costs less than the claim is worth.
And record the outcome in the plant's documentation. The next owner inherits both the equipment and its history, and a refused claim is part of what they need to know.
The short version
- Four instruments with four counterparties: module product warranty, module performance warranty, installer guarantee, inverter warranty
- Claims need a baseline, irradiance-corrected performance, evidence the obligations were met, fault documentation, and the original papers
- Unmet obligations are the commonest reason a claim fails, and they fail it regardless of merit
- Establish the shortfall, check the deadline, notify in writing within it even if the investigation is incomplete, then gather the rest
- A late claim with good evidence loses to a timely one with partial evidence
- On refusal, ask for the specific clause in writing, consider an independent measurement report, and record the outcome for the next owner