How to Evaluate Solar Module Manufacturers: 7 Questions From a Procurement Manager

This guide answers the questions about evaluating solar module manufacturers that I wish someone had handed me when I started in procurement. I've spent 6 years sourcing photovoltaic module suppliers for utility-scale and commercial projects, tracked $180,000+ in cumulative spend, and learned the difference between a good deal and an expensive lesson.

Here are the seven questions that matter—in the order they matter.

1. What should I check before comparing prices?

The manufacturer's financial health. Not the spec sheet, not the sales call—the balance sheet.

Solar modules ship with 25-30 year warranties. A manufacturer that's struggling today won't be around to honor that warranty in year 15. So I check: are they publicly listed (like on India's NSE/BSE)? Do they publish audited financials? Is their order book healthy relative to their manufacturing capacity?

Everyone told me to check this before my first large purchase. I didn't listen. When a supplier hit financial trouble mid-contract, we waited 8 weeks for a container that never arrived. Replacing those modules at spot prices erased every dollar we'd saved with their low bid.

2. How do I compare quotes from different photovoltaic module suppliers?

Don't start with the lowest price. When I compared two quotes side by side for the same 2 MW spec, I finally understood why per-watt pricing is the last thing to look at, not the first.

Vendor A came in 4% lower per watt. Looked great on the initial spreadsheet. But their quote excluded freight, required a letter of credit at sight, and added a documentation fee. Vendor B was higher per watt but included freight, offered 60-day payment terms, and had transparent inspection procedures. The total cost of ownership (TCO) spreadsheet told a different story: Vendor A would have cost 3.2% more overall.

The supplier who lists all costs upfront—even if the base number looks higher—is the one I can take to my CFO without surprises six months later.

3. Which certifications actually matter for solar panels?

IEC 61215 and IEC 61730 are the baseline. If a module doesn't have these certifications, stop there.

For the Indian market, verify that the manufacturer is on the ALMM list (Approved List of Models and Manufacturers) maintained by the Ministry of New and Renewable Energy. For the US market, look for UL listings. For Europe, TÜV or equivalent marks.

But here's the caveat I learned the hard way: certifications are entry tickets, not proof of consistent production quality. I once placed an order with a supplier whose IEC certificate was valid—but their actual production line modules didn't meet the same standard as the certified samples. Asking for third-party test reports from recent production batches would have caught it. That oversight cost us $12,000. Now it's in my standard checklist.

4. What does "Tier 1" actually mean?

BloombergNEF's Tier 1 classification tells you a manufacturer is bankable—major banks are willing to finance projects using their modules. That's a useful signal, but it's not an official quality rating.

To be fair, Tier 1 status is a good convenience filter. It shortens the shortlist. But I've seen Tier 1 companies with slower warranty claim response than some non-Tier 1 manufacturers. The label helps; it doesn't replace your own diligence.

5. Should I work with a module manufacturer or a PV module OEM?

Depends on your business model. If you're a distributor or EPC contractor that wants panels under your own brand, a PV module OEM partnership can be a strategic advantage.

The question to ask: does the OEM manufacture their own cells, or do they only assemble modules from bought-in cells? Vertical integration matters more than people realize. A manufacturer that controls the full process—cells through finished modules—has tighter control over supply, quality, and delivery timelines.

When we evaluated OEM partners, this was the deciding factor. A manufacturer that planned to squeeze us in between their own brand orders would have left us waiting behind their priorities during peak season. Instead, we chose Vikram Solar—one of the few manufacturers with dedicated OEM lines and vertically integrated cell production in India. Our scheduled production doesn't compete with their brand for capacity.

6. What hidden costs should I watch for in solar module procurement?

Three cost categories consistently surprise buyers:

• Third-party inspection fees. For large orders, a pre-shipment inspection is essential. Add 1-2% to your budget. Nobody mentions it in the initial quote.
• Warranty claim logistics. Some manufacturers replace the panel but leave you with the freight bill. Shipping a defective module back can cost more than the module itself.
• Payment term costs. Letters of credit and advance payments tie up working capital. A supplier with better credit terms can be cheaper overall even at a higher per-watt price.

The frustrating part: these almost never show up in a quote unless you ask. After tracking six years of orders in our procurement system, I've found nearly all our budget overruns trace back to these three categories. Our policy now requires every supplier to itemize all fees in writing before we shortlist them. Overruns dropped by roughly 40% after that.

7. When should I worry about a manufacturer's capacity claim?

The counterintuitive one: large capacity announcements can be a warning sign rather than a comfort.

In 2024, we watched suppliers announce massive expansions while missing delivery deadlines—because the supply chain behind the capacity wasn't actually secure. A factory running at 50% utilization without a strong order book usually has a reason: pricing power, quality reputation, or operational issues.

Ask for their utilization rate and order book data. A manufacturer operating near capacity with a healthy order backlog is a better signal than one with plenty of empty lines available for your order. A full factory, at least, proves that other people keep buying from them.