Industry Perspectives on c-Si PV Module Reliability and the Rise of Comparative Testing

Discerning buyers understand that seemingly identical PV modules may perform very differently over 20 or 30 years. But how can they take that knowledge to the bank?

On the opening day of Intersolar North America 2013, NPD Solarbuzz announced that installed PV capacity in the US had recently surpassed 10 GW. While the compound annual PV capacity growth rate has exceeded 50% since 2007, roughly 8.3 GW of capacity was installed between Q1 2011 and Q2 2013. This impressive build-out is largely due to a rapid expansion of the utility sector and collapsing module prices, both of which have contributed to dramatic PV system price declines.

According to “US Solar Market Insight Report: 2012 Year in Review,” part of a series published quarterly by GTM Research and the Solar Energy Industries Association (SEIA), more than 3.3 GW of PV capacity was installed in the US in 2012. With the utility sector accounting for 53% of this capacity, the weighted average PV system price came in at $3.01 per watt, which is lower than the average selling price (ASP) for a PV module circa 2007 or 2008. By comparison, the ASP for a PV module fell from $1.15 per watt in Q4 2011 to $0.68 per watt in Q4 2012, a precipitous 41% decline, before leveling off somewhat at $0.64 per watt in Q1 2013.

Arguably, there has never been a better time to purchase PV modules. Prices are hovering at or near record lows. But at what cost to the industry? While falling module prices are generally seen as a sign of progress, the rate at which module prices have fallen over the last 18–24 months is potentially problematic. In “Solar PV Profit’s Last Stand” (, March 2013), Paula Mints notes that a “42 percent decrease in price in one year is not progress by any logical assessment,” because it is not “representative of true learning.” True progress, Mints suggests, is sustainable, as when price declines generally track a learning curve or a technology road map. She likens the current market conditions, in which manufacturers are pricing at a loss to garner or preserve market share, to a nightmare.

If this is a nightmare, it is one that some companies will not wake up from. Since 2008, Greentech Media has followed the fortunes of more than 200 VC-funded solar startups, publishing regular updates on the growing list of shuttered or restructured solar firms (see “Rest in Peace: The List of Deceased Solar Companies” for the most recent article). The list includes some well-known crystalline silicon (c-Si) PV module manufacturers, including Bosch, BP, Evergreen, Q Cells, SCHOTT Solar, Solon, Siliken and Suntech Power. According to a recent GTM Research report “Global PV Module Manufacturers 2013: Competitive Positioning, Consolidation and the China Factor,” more companies are expected to join this list. Having analyzed the facilities, financial health and business models for more than 300 module manufacturers, GTM Research concludes that 180 existing manufacturers will either go out of business, exit the market or undergo an acquisition between 2013 and 2015.

While module manufacturing is undoubtedly ripe for consolidation, our “2013 c-Si PV Module Specifications” table (see sidebar) suggests that the real shakeout is yet to come. This table includes abbreviated specifications for 849 module models from 62 manufacturers. Surprisingly, these totals have remained substantially unchanged since SolarPro magazine published module data for 2012. All of these PV modules are certified to UL 1703 and eligible for rebates under California Solar Initiative programs; all of the manufacturers have established North American distribution channels.

Given the challenging competitive environment facing module manufacturers, purchasers are wise to keep this adage in mind: caveat emptor, “let the buyer beware.” In last year’s c-Si PV module article (SolarPro magazine, October/November 2012), Publisher Joe Schwartz focused on manufacturer profiles, addressing one major concern for purchasing agents—namely, “From whom am I buying?” This article takes a closer look at module reliability, quality assurance and performance. With the help of a cross-section of industry experts and stakeholders—representatives from module manufacturers, testing labs, material suppliers, project developers and plant constructors—I address an increasingly important follow-up question: “How do I know that the c-Si PV modules I am buying today will last for 20 or 30 years and provide the performance that I am banking on?”

Beyond Certification and Qualification Testing

An important first step for anyone purchasing PV modules is to determine who performed what product testing. For example, Nationally Recognized Testing Laboratories (NRTLs), which are private-sector organizations recognized by OSHA, currently offer two types of testing programs for c-Si PV modules: safety certification and design qualification.


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