Module warranties are usually compared by their headline numbers: years of product cover, years of performance cover, and a final output percentage. Those numbers describe what a manufacturer has promised. They say much less about what happens when someone tries to use that promise. In May 2026, the Ministry of New and Renewable Energy addressed this directly. MNRE issued a standard procedure for warranty management and claims settlement for modules installed under its distributed renewable energy programmes, mandating a 10-year product warranty and a 25-year power output warranty. The framework sets rules for proving a defect, timelines for responding, and the conditions under which a claim can be refused. It applies to MNRE schemes such as PM Surya Ghar and PM-KUSUM, but for EPCs and developers on any project, it is a useful map of where module warranties tend to break down.
Two Promises With Different Triggers
A product warranty covers the module as a manufactured object. When MNRE set requirements for modules enlisted under PM Surya Ghar, it specified a product warranty of at least ten years from commissioning, covering manufacturing defects. Delamination, junction box failures, frame defects and faulty internal connections fall here. The trigger is a physical fault, and the usual remedy is repair or replacement.
A performance warranty covers output. It guarantees that the module will still produce a minimum share of its rated power at set points over its life, and the trigger is a measured shortfall against that guarantee. The two can come apart. A module can look perfect and still fail its performance warranty. A module with a cracked frame can still be producing its guaranteed output.
Timing adds another layer. Product warranties are much shorter than performance warranties, so the same defect can be covered differently depending on when it appears. Take a module with a 12-year product warranty and a 30-year performance warranty. Delamination in year 8 is a product claim, and the module is repaired or replaced whatever its output. The same delamination in year 14 is only claimable if it pulls output below the performance line, because the product cover has already expired. Buyers who know both terms can tell which warranty applies to a defect and what evidence it will need. A product claim rests on inspection. A performance claim rests on measurement, which is where most of the difficulty lies.
How a Performance Shortfall Gets Proven
Performance warranties are measured against standard test conditions, a fixed laboratory setting of light intensity and cell temperature that real plants almost never match. A string producing less than expected on site does not, on its own, prove that any module has breached its warranty. Soiling, shading, inverter limits, heat and wiring losses all sit between a module’s rated output and what the meter records.
Proving a shortfall means taking the module out of that noise and measuring it properly. MNRE’s procedure prescribes field testing that includes electroluminescence and I-V testing, and requires NABL-accredited laboratories wherever laboratory assessment is needed. EL images show whether physical damage is behind the loss. I-V measurements show how far output has actually fallen.
Measurement tolerance then decides whether that shortfall counts. Every flash test carries some uncertainty. GREW Solar’s G12R DCR datasheet, for example, states a measurement uncertainty of ±3%. In practice, a module that tests a point or two below its guaranteed level may still sit inside that margin, and most warranties allow for it before accepting a claim. The terms that decide whether a claim is worth pursuing are agreed before signing: how tolerance is applied, which party arranges and pays for testing, and who covers removal and shipping of modules sent to a lab. These are the clauses worth comparing line by line when evaluating quotes from solar panel suppliers in Gujarat or anywhere else.
Response time matters too. Under the SOP, manufacturers must acknowledge complaints within 48 hours and complete replacements within set timelines that depend on defect severity and component availability. Outside the schemes it covers, those timelines are whatever the supply contract says, and many contracts say nothing.
Linear, Stepped and the First-Year Allowance
The shape of the guaranteed curve decides when a shortfall can be claimed at all. Older warranties were stepped, guaranteeing fixed floors at only a few points. Rooftop specifications issued under MNRE’s earlier grid-connected rooftop programme, as reproduced in state tender documents, required more than 90% output for the first 10 years and more than 80% across the following 15. A linear warranty instead sets a guaranteed value for every year of the term. Most linear warranties also allow a larger drop in the first year than in the years after, then a smaller fixed reduction each year.
GREW Solar’s G12R DCR carries a linear performance warranty that allows 1% degradation in the first year and 0.4% a year from year 2 to year 30, alongside a separate 12-year product warranty. Working from those datasheet figures, guaranteed output is 94.6% of rated power at year 12, 89.4% at year 25 and 87.4% at year 30.
The difference between the two structures shows most clearly in the middle years. Consider a hypothetical module that measures 86% of its rated power in year 12. Under the older stepped floors, it passes, because anything above 80% is acceptable after year 10. Under the G12R’s linear terms, the same reading is more than eight points below the year-12 guarantee and is a clear claim. Both warranties could be described as 25 years or longer. Only one of them would cover that module.
Exclusions and the Paper Trail
Every warranty excludes certain causes of failure, and MNRE’s SOP is unusually specific about which ones. Its exclusions fall into three broad groups.
The first is how the module was installed. Manufacturers can refuse claims where damage or underperformance comes from installation that breaks the manufacturer’s manual, BIS or IEC standards, or structural norms. Unauthorised repairs, modifications and replacement parts also void cover.
The second is where it was installed. Modules in corrosive or harsh environments can lose protection if adequate safeguards weren’t in place. For coastal sites, saline exposure, corrosion-prone areas and chemical industrial zones, the SOP requires testable evidence and compliance with the relevant standards before a claim is accepted. Damage from improper voltage, power surges, shading or heat stress is also excluded where testing establishes those conditions as the cause.
The third is what happened to the module. Glass broken by external impact, shipping damage after invoicing, misuse, negligence, tampering and poor handling are classed as non-warranty events. Force majeure is limited to natural disasters such as earthquakes, floods and cyclones. Wars, riots and commercial or logistical disruptions cannot be used to deny a claim.
Most of these exclusions come down to one question: did the problem exist before installation, or did the site or the installation cause it? The buyer is usually better placed than the manufacturer to answer that, provided the right records exist. EL images and I-V readings taken at commissioning give a baseline that separates factory defects from later damage. Installation records and photographs show the manual was followed. Cleaning and maintenance logs answer shading and soiling objections. A register linking each module’s serial number to its string position makes it possible to trace a failing module back to its delivery batch and test records. Asking solar panel suppliers in Gujarat for the installation manual and the full warranty document at quotation stage, alongside the datasheet, gives the project team time to build these records into the installation plan rather than reconstructing them during a dispute.
MNRE has also proposed linking warranty certificates to the national DCR portal, creating traceable digital records for rooftop consumers under government schemes. Utility-scale and C&I projects outside those schemes have nothing equivalent yet, and their warranties are only as enforceable as the records kept against them.
That gap is unlikely to last. Once one part of the market has defined timelines, testing protocols and a fixed list of exclusions, buyers elsewhere have a template to negotiate from. Over the next few procurement cycles, the strength of a module warranty will increasingly be judged by its claims process, not by the number of years on the datasheet.
