Large-Format PV Module Evaluation
One of the most widely discussed topics today relates to an industry-wide pivot toward large-format PV module designs.
Lowering costs, improving performance, and increasing the speed of deployment are essential to the solar industry’s ability to compete with fossil fuel power sources. The industry’s collective ability to drive costs out of the project value chain over the past decade is one of the primary reasons that solar is expected to account for the largest share of new U.S. electricity generation capacity in recent years.
Today, one of the most promising opportunities for continued cost reductions, both at the module level and the system level, relates to the development and deployment of large-format PV modules. The value proposition is so compelling that some industry analysts expect large-format modules to account for 90% of the market by 2025.
Large-format PV module designs were ubiquitous at RE+ 2022 in Anaheim.
BENEFITS OF LARGE-FORMAT DESIGNS
The high-level benefits of large-format PV modules are obvious to see. Larger wafers and cells—typically, 182 mm or 210 mm square—facilitate larger form factor modules. These new modules are generally more than two meters long and have capacity ratings ranging from 500 watts to more than 800 watts. For an industry long accustomed to incremental increases in module capacity, this is a huge jump in power.
The value proposition for large-format PV modules is multilayered. At the manufacturing level, large-format modules facilitate efficiencies of scale that drive down production costs and reduce the cost per watt downstream. In terms of material handling, fewer numbers of higher-capacity modules provide logistical efficiencies and drive down in-field labor costs. At the system level, large-format modules also facilitate an increase in energy density, higher power source circuits, and potential balance of system (BOS) savings.
Hongbin Fang, LONGi Solar’s director of product marketing, notes that, “In the last couple of years, large-format modules have been an effective way to improve module power, achieve lower manufacturing cost and help customers to reduce BOS cost. As a result, large-format modules have helped the industry accelerate the process of achieving a lower levelized cost of energy (LCOE).”
TRADEOFFS WITH LARGE-FORMAT DESIGNS
When evaluating large-format modules for specific projects and applications, it is important to keep in mind that upfront savings may come at a cost. Some risk and uncertainty is inherent to any new product or technology with limited field exposure. However, large-format modules also present some unique challenges.
From a structural point of view, large-format PV modules expose a larger area to the same amount of wind for a given location. This larger module may have the same thickness of glass and the same frame as its smaller-format predecessors, effectively increasing per-module wind loads. Especially in high-wind areas or high-elevation locations with extreme snow loads, large-format modules may increase project risk or long-term operating costs.
Hail durability test data also indicates that large modules with thinner front glass are less resilient to large-diameter hail than previous module designs. This is in part a function of the fact that thinner glass has less area to absorb a shock without shattering. More critically, thinner front glass materials—common in bifacial modules with a glass-on-glass package—cannot be tempered via traditional means and must be strengthened via alternative methods, such as chemical treatments.
Large-format module designs may be less resilient to wind, snow, and hail.
MEETING THE CHALLENGE
Until large-format modules are a proven commodity in geographically diverse field applications, project stakeholders need to assess these products carefully based on the specific installation environment and highly accelerated life testing data. Moreover, the industry needs to ensure that its testing protocols and sequences are adequate to capture potential failure modes and wearout mechanisms in modules that may be subject to higher mechanical stresses, including heavy snow loads and dynamic wind effects.
“Innovation and improvements need to withstand a 25- to 30-year project life,” notes Vikash Venkataramana, technical director for Jinko Solar. “Performance in extreme environments needs to be guaranteed. This is where extended reliability testing helps the industry move forward. By validating module performance through third-party accelerated testing, we are able to make technology advances in the industry while maintaining quality and reliability.”
At the end of the day, the risks and rewards associated with large-format modules are not equitably distributed. For module manufacturers, the trend toward large-format modules is an opportunity to increase profit margins and differentiate themselves in the market. For developers and EPCs, this cost-saving opportunity may increase close rates and market share.
In the event that in-field reliability and performance suffer, insurance companies and financiers are likely the ones footing the bill. It is important, therefore, that sponsors, underwriters, and IEs ask the right questions and review relevant testing data when qualifying large-format modules, especially for locations subject to extreme weather.
A version of this article originally appeared in RETC’s