A solar project is a long-term commitment. Modules installed today are expected to generate for decades, and the warranty is the document meant to back that expectation. On most quotations, though, it is reduced to a single line such as “30-year warranty,” which says little about what is covered, how a claim works, or who will honour it. In May 2026, the Ministry of New and Renewable Energy 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 procedure covers MNRE schemes. The questions it answers apply to every project: what each warranty promises, how degradation is guaranteed, and which conditions decide whether a claim succeeds.
Two Warranties Covering Two Different Risks
The product warranty covers the module as a manufactured object, protecting against defects in materials and workmanship. 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 failed cell interconnections fall under this cover, and the remedy is usually repair or replacement.
The performance warranty covers output. It guarantees that a module will still produce a minimum share of its rated power after a stated number of years, and it typically runs much longer than product cover. The gap between the two terms is where many buyers are caught out. A 30-year performance warranty paired with a 12-year product warranty means a manufacturing defect in year 14 is only claimable if it pulls output below the guaranteed line. A defect that leaves output intact is no longer covered.
How Degradation Is Built Into the Guarantee
Every module loses some output over its life, and the performance warranty defines how much loss is acceptable. Most warranties handle this in two stages. The first year allows a larger drop, reflecting the initial settling a module goes through once it starts operating. A smaller fixed reduction then applies to every year after. N-type TOPCon modules are generally warranted with a lower first-year allowance than older p-type designs, which is why their guaranteed curves start from a higher point.
Terms commonly seen on n-type modules illustrate how the curve works in practice. With a 1% first-year allowance and 0.4% a year afterwards, guaranteed output is 99.0% at the end of year 1, 95.4% at year 10, 89.4% at year 25 and 87.4% at year 30. On a 10 MWp plant, that means at least 9.54 MWp of guaranteed capacity at year 10 and 8.74 MWp at year 30.
Small differences in the annual rate compound over that period. At 0.5% a year instead of 0.4%, guaranteed output at year 30 falls to 84.5%, almost three points lower. On the same 10 MWp plant, that is around 290 kWp of capacity the warranty no longer protects by the end of its term. This is why financial models should use the warranted degradation rate, or a more conservative one, and never assume output holds flat.
Linear and Stepped Guarantees
The structure of the curve matters as much as its end point. A stepped warranty guarantees output at a few checkpoints only. 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. Between those checkpoints, a module can decline steadily without breaching anything.
A linear warranty guarantees a minimum output for every year of the term. It is simpler to model, it allows a shortfall to be identified as soon as it occurs, and it gives tighter protection overall, which is why project financiers generally prefer it. Under the linear terms above, a module reading 86% in year 12 is well below its 94.6% guarantee. Under the older stepped floors, the same reading would pass.
What Stands Behind the Warranty
A warranty is only as strong as the company that has to honour it, possibly decades from now. Manufacturer track record, financial standing and acceptance by lenders all bear on that, and our article on what makes a solar module bankable covers those factors in detail. Some manufacturers also back their warranties with third-party insurance, which is designed to keep claims payable if the manufacturer itself runs into difficulty. Domestic manufacturing and service operations can shorten the path from complaint to inspection to replacement, though the contract, not the address, is what sets the timeline.
For projects under MNRE schemes, the SOP now fixes part of that timeline. Manufacturers must acknowledge complaints within 48 hours and complete replacements within set periods based on defect severity and component availability. Outside those schemes, response times are whatever the supply agreement specifies, which is a strong reason to specify them.
The Terms That Decide a Claim
The conditions attached to a warranty usually matter more than its headline years, and they fall into three areas.
The first is how a claim is proven. A performance claim depends on measurement, and MNRE’s procedure prescribes field testing including electroluminescence and I-V testing, with NABL-accredited laboratories used wherever lab assessment is needed. Measurement tolerance then decides whether a shortfall counts. GREW Solar’s G12R DCR datasheet, for example, states a measurement uncertainty of ±3%, so a module testing slightly below its guaranteed line may still fall within that margin.
The second is what the remedy actually covers. Warranties may offer repair, replacement or a pro-rata payment for lost capacity. Some cover only the replacement module, leaving the costs of removal, transport and reinstallation with the owner. Whether the warranty transfers to a new owner if the plant is sold or refinanced matters for any asset expected to change hands. It is also worth confirming that the stated terms apply to the exact module variant being purchased, since warranty periods can differ between products in the same range.
The third is what voids cover. Under MNRE’s SOP, manufacturers can refuse claims where damage results from installation that breaks the manufacturer’s manual, BIS or IEC standards, or structural norms. Unauthorised repairs and modifications void cover as well, and installations in coastal, saline, corrosion-prone and chemically classified industrial zones require testable evidence and compliance with prescribed standards. Requirements around system voltage, grounding and mounting sit in this category too, which makes the installation manual a contractual document, not just a technical one.
Quality That Reduces the Need to Claim
The most valuable warranty is the one a project never has to use, and manufacturing quality largely decides how likely that is. Electroluminescence testing at several production stages, demonstrated PID resistance, positive power tolerance and test reports from accredited laboratories all lower the chance of underperformance. Our articles on EL testing, PID and ALMM certification explain how each relates to module quality in India.
Indian Conditions and What Warranties Leave Out
India’s heat, humidity, dust and monsoon place real stress on modules, and conditions vary sharply between Rajasthan’s dry interior, Gujarat and the coastal belts. Warranties are written around standard tests, so a module’s construction, encapsulation and glass need to suit the site’s environment. Soiling and shading reduce output without counting as degradation. MNRE’s SOP also excludes damage from improper voltage, surges, shading and thermal stress where testing establishes them as the cause. A cleaning and maintenance plan protects yield in ways no warranty will.
Comparing Warranties on Equal Terms
Comparing quotations on warranty years alone hides the differences that matter. A meaningful comparison sets the terms side by side: product and performance periods, first-year and annual degradation, linear or stepped structure, the claims process and testing standard, exclusions, and the strength of the company backing the warranty. Asking solar panel suppliers in Gujarat for the full warranty document and installation manual at quotation stage, not only the datasheet, brings these terms into the evaluation early. Testing the answers against a modelled degradation curve shows which offer actually protects the project, and that discipline separates a sound procurement from a quotation that simply reads well. Quotes from solar panel suppliers in Gujarat that state degradation year by year make this comparison far easier.
GREW Solar’s G12R module carries a 15-year product warranty and a 30-year linear performance warranty, with 87.40% assured power output at the end of year 30. Project-specific terms are confirmed in the supply agreement. Developers and EPCs comparing module warranties for upcoming projects can contact GREW Solar for the full warranty document and degradation schedule for their chosen module.
As module technology improves and warranty terms lengthen, the headline years will matter less to buyers. What will matter more is how precisely a warranty is written, and how well its claims process holds up decades after installation.
