Advantages (and tradeoffs) of large-format PV modules

By Contributing Author July 18, 2023

This is an excerpt from the Q2 2023 difficulty of Solar Builder journal, written by Cherif Kedir, president and CEO on the Renewable Energy Test Center (RETC), an accredited testing laboratory for solar photovoltaic and energy storage merchandise. Subscribe to Solar Builder journal at no cost (print or digital) proper right here.

Lowering prices, bettering efficiency, and rising the pace of deployment are important to the solar {industry}’s skill to compete with fossil gas power sources. Our collective skill to drive prices out of the undertaking worth chain is among the major causes solar accounted for 50% of all new electricity-generating capability additions within the U.S. final yr.

Today, one of the crucial promising alternatives for continued value reductions, each on the module and system stage, pertains to growing and deploying large-format PV modules. The worth proposition is so compelling that some {industry} analysts count on large-format modules to account for 90% of the utility market by 2025. Recently, large-format product adoption has began increasing past the utility sector into distributed era (DG) markets.

In this text, I discover what’s driving the industry-wide pivot to large-format PV modules. I additionally think about distinctive technical dangers of those new merchandise and advocate strategic threat mitigation approaches. In sharing these insights, my aim is to not advocate or vilify a particular product, expertise, or producer — moderately, it’s to empower you to determine and specify the perfect merchandise and system designs in your distinctive functions.

Large-format advantages

The high-level advantages of large-format PV modules are simple to see. Larger wafers and cells — usually 182 mm (M10) or 210 mm (M12) sq. — facilitate bigger kind issue modules. These new modules are typically greater than 2 m lengthy and have capability scores starting from 500 W to greater than 800 W.

For an {industry} lengthy accustomed to incremental module capability enhancements, super-sized PV modules signify an enormous leap in module-level output power scores. Year-over-year cell-efficiency will increase usually end in output power positive aspects of 10 W to fifteen W yearly. By comparability, the swap from a conventional M6 (166 mm sq.) wafer format to M10 or M12 wafers would possibly enhance the module-level output power by 100 W to 150 W.

The worth proposition for large-format PV modules is multilayered.

  • At the manufacturing stage, large-format modules facilitate efficiencies of scale to drive down manufacturing prices.
  • Further downstream, large-format modules promise extra cost-per-Watt financial savings, as dealing with fewer higher-capacity modules for a similar plant capability gives logistical efficiencies and drives down in-field labor prices.
  • At the system stage, large-format modules enhance source-circuit power ranges, improve plant-level energy density and facilitate steadiness of system (BOS) financial savings.

Hongbin Fang, LONGi Solar’s director of product advertising and marketing, notes, “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).”

Large-format tradeoffs

large format module comparison

When evaluating large-format modules for particular tasks and functions, keep in mind that upfront financial savings might come at a value. Some threat and uncertainty are inherent to any new product or expertise with restricted subject publicity. However, large-format modules additionally current some distinctive challenges.

From a structural viewpoint, large-format PV modules expose a bigger module floor space to the identical environmental stresses for a given location. All else being equal, bigger modules are inherently topic to a rise in physique deflection and torsion in comparison with smaller modules. As a outcome, the silicon cells in these modules are topic to elevated mechanical stress and strain. In apply, nonetheless, all else isn’t held equal as module floor space will increase.

To counteract the 20% to 30% enhance in module floor space, it isn’t unusual for producers to cut back glass and module body thickness in an effort to manage weight. This convergence of variables — characterised by heavier however thinner module glass, longer however lower-profile aluminum perimeter frames, and a bigger floor space — invariably ends in a weaker module.

RETC’s hail sturdiness check knowledge signifies that enormous modules with thinner entrance glass are much less resilient to extreme diameter hail than earlier module designs. This vulnerability is partly a operate of the truth that thinner glass has much less cross-sectional space to soak up a shock with out shattering. More critically, warmth tempering requires a minimal glass thickness (≥3.2 mm). Many large-format bifacial modules have a 2.0 mm glass-on-2.0 mm glass bundle. This “heat-strengthened” glass isn’t as robust as tempered glass.

Large-format modules might also enhance dangers related to accelerated efficiency degradation or long-term working prices in high-wind areas or high-elevation areas with excessive snow hundreds. Elevated environmental stresses will are likely to exacerbate deflection and torsion in large-format PV modules, rising the potential for cell cracking. As cell cracks enhance in severity, so does the chance of efficiency degradation, service life discount and hotspots.

Meeting the problem

Until large-format modules are a confirmed commodity in various environments and market sectors, undertaking stakeholders should fastidiously assess these merchandise primarily based on the particular set up setting and extremely accelerated life testing knowledge. Moreover, the {industry} wants to make sure its testing protocols and sequences are enough to seize potential failure modes and wearout mechanisms in modules topic to greater mechanical stresses, together with heavy snow hundreds and dynamic wind results.

“Higher power class modules are here to stay,” says Daniel Chang, senior director of solar product administration at Qcells North America. “But these product innovations still need to withstand a 25- or 30-year project life in extreme environments. This is why beyond-certification testing in the laboratory is so important. By validating product designs via highly accelerated third-party testing, the industry is able to bring innovative products to market while ensuring long-term durability and performance.”

At the tip of the day, the dangers and rewards related to large-format modules usually are not equitably distributed. For module producers, the pattern towards large-format modules is a chance to extend revenue margins and differentiate themselves available in the market. For builders and EPCs, this cost-saving alternative might enhance shut charges and market share.

In the occasion that in-field reliability and efficiency undergo, host clients, insurance coverage corporations and financiers are doubtless those footing the invoice. Therefore, these undertaking stakeholders and their technical advisors should ask the correct questions and overview related testing knowledge when qualifying large-format modules, particularly for areas topic to excessive climate.

Super-sized in resi, C&I

The utility undertaking sector is ideally suited to leveraging economies of scale. As such, module corporations developed the primary PV modules to combine M10 and M12 cells with 1,500-volt ground-mounted functions in thoughts. Today, increasingly more producers supply super-sized PV modules for distributed era (DG) functions.

Especially in behind-the-meter rooftop functions, you will need to holistically consider the professionals and cons of large-format merchandise.

Product storage: For some producers, the pivot to large-format module designs coincides with progressive packing configurations that optimize container utilization. In some circumstances, producers palletize modules in a vertical format, which can necessitate warehouse compatibility upgrades. On the jobsite, pallets with a smaller base space and taller heart of gravity might require particular consideration to forestall tipping. Pay consideration to level load limits when staging low-slope rooftops.

Material dealing with: Large-format modules are incompatible with single-person dealing with, which can influence optimum crew dimension, workflow and jobsite security. Bigger and heavier modules will enhance crew member fatigue, probably requiring extra relaxation and hydration breaks. In some circumstances, present rooftop transportation practices will likely be incompatible with larger-format merchandise. If so, think about investing in rooftop transport gear that improves jobsite security and undertaking throughput. Pay consideration to car or trailer load limits throughout transportation.

Design flexibility: Bigger isn’t all the time higher in space-constrained functions. On the one hand, high-power product designs scale back the module rely for a given undertaking capability. On the opposite hand, large-area modules might restrict array structure choices. This problem is very true for rooftop tasks with many obstructions.

BOS compatibility: Integrating large-format PV modules into DG functions might require totally different power electronics and racking parts as in comparison with business-as-usual techniques. Designers might not expertise BOS compatibility issues with techniques designed from scratch with high-power modules in thoughts. However, substituting large-format modules for typical merchandise might require re-engineering and procuring various merchandise.

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Tags: industrial and industrial, RETC

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