Are bigger PV modules better?
After the industry switched to larger wafer sizes in 2019, the trend towards larger PV modules—exceeding 2 meters in size and 500 W in power output—has become prominent. These advancements bring both opportunities and challenges in system design, installation, and long-term operation.
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Does larger always mean better?
For Tier-1 PV manufacturers, larger formats offer clear benefits. By adapting equipment, they can produce 600 W modules as quickly as 400 W ones, effectively increasing production capacity. This shift could widen the gap between larger producers and smaller ones unable to keep up.
While these high power ratings are impressive, they often stem from size increases rather than groundbreaking innovations. The introduction of half-cut cells enabled this shift, with further improvements in interconnection strategies and reduced cell gaps contributing to increased active surface area. For manufacturers heavily invested in PERC technology, larger formats offer a way to boost energy yield and lower LCOE at the project level, providing value comparable to other innovations.
Promises and concerns
Manufacturers claim that larger modules not only optimize their costs but also reduce system design expenses, leading to lower LCOE at the project level. One key promise is that more powerful modules will reduce costs for trackers and racking systems. With proper orientation, racking only needs minor adjustments to accommodate more modules, thereby maximizing watts per pile.
Another benefit is that cut cells, multibusbar interconnection, and twin-module designs lower module voltage, allowing more energy capacity within the same space. For example, Canadian Solar’s new Series 7 modules enable over 30 modules per string, pushing power per string up to 20.2 kW, compared to 12.2 kW from older models.
However, concerns have arisen over the increased size. Thinner front glass makes some modules more fragile, though manufacturers like Trina Solar have addressed this with reinforced metal frames. Higher currents from lower voltage modules also raise the risk of hotspots, though design innovations aim to mitigate this. Additionally, the size and weight of these modules pose challenges in shipping and installation, although manufacturers have optimized packaging and installation methods to manage these issues.
Large and larger modules
The industry’s shift to larger wafers has divided it into camps: those supporting the 182 mm wafer and those pushing for the 210 mm wafer. While manufacturers are hedging their bets by preparing for both sizes, the choice between them involves trade-offs. The 210 mm wafer offers a significant power increase but requires major system redesigns, whereas the 182 mm wafer provides a more gradual, less disruptive path to higher energy yields.
Trina Solar’s case study of its Vertex module, using 210 mm cells, showed a 35.8% increase in power per string compared to a competitor’s 182 mm module. This translated into substantial savings in materials and installation costs. However, the larger 210 mm modules necessitate redesigns at the tracker, inverter, and system levels, which introduces uncertainty and higher risks.
In contrast, 182 mm modules, which still deliver power outputs well above 500 W, require only minor adjustments to existing components and layouts. This makes them the most mature and bankable product currently available, with many in the industry favoring this less disruptive option.
Conclusion: The future of large PV modules
As the industry continues to evolve, both 182 mm and 210 mm wafer sizes are here to stay. Analysts predict that these two formats will dominate the market by 2025, with 210 mm gradually gaining ground as it establishes itself. While larger modules offer significant benefits, their adoption will depend on the ability of manufacturers and project developers to navigate the associated risks and challenges.
In the short term, the 182 mm format appears to be the safer, more reliable option, while the 210 mm format represents a bold step into new territory. The future success of these larger modules will hinge on their ability to deliver on their promises while maintaining cost-effectiveness and reliability.
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