Rectangular module: Trends and prospects

Driving module efficiency up and costs down has long been the major focus of the solar development. Wafer size plays a crucial role in efficiency performance. As wafers became larger, module efficiency has improved markedly, while balance of system (BOS) costs has declined significantly, thereby optimizing the LCOE of solar generation. Having experienced several times of size changes, however, the development of mainstream size is becoming more dramatic and diversify. With the introduction of large format wafer in 2019, its advantages in cost reduction enabled its rapid market penetration. Consequently, demand for M6 (166*166 mm) and smaller sizes dropped at a fast pace, with only 2% of market share remaining in 2023.

M10 (182*182mm) and G12 (210*210mm) have gradually become the mainstream sizes since 2022, but module makers continued to introduce wafers in rectangle sizes that integrate their module layouts, including 182.2*183.5mm, 182.2*183.75mm, 182.2*185.3mm, 182.2*186.8mm, 182.2*188mm, 182.2*191.6mm, 182.2*199mm, and 182.2*210mm, to enhance their product competitiveness. Varied wafer sizes brought chaos and inconvenience to the industry, with customized wafer sizes challenging non-vertically integrated companies in terms of purchase and sales, as well as supply chain management ability. To end users, it’s challenging their design and management with too many module sizes on the market. Therefore, sectors across the supply chain have been calling for standardizing wafer size.

To improve module efficiency, reduce system costs and optimize the use of 40-foot containers, nine leading manufacturers including Canadian Solar, Risen, JA Solar, Jinko, Longi, Trina, Tongwei, DAS Solar, and Astronergy have reached a consensus on the standard module dimensions of 2382*1134mm for the new generation rectangular modules and signed the Initiative on Standardization of Rectangular Silicon Wafer Module Dimensions to establish the standard for module development.

Under the initiative, manufacturers can produce standard modules within the range of 182mm and 210mm wafers to meet their customer needs, confirming that 66-cell, 72-cell, 2382*1134mm modules will adopt either 182.2*191.6mm or 182.2*210mm size in the future.

Six major manufacturers including Canadian Solar, Risen, Longi, DAS Solar, Tongwei, and Astronergy reached a consensus on rectangle module size of 182.2*191.6mm in August 2023. The size can be used to produce 72-cell, 2382*1134mm modules, but when it is used to produce 54-cell, 1800*1134mm modules, the module area will be larger than 2m², which violates Germany’s regulation for rooftop solar installation of less than 2m² (only Hessen has removed such area limitation so far), causing concerns among many manufacturers. On the other hand, 48-cell, 1762*1134mm modules that made by 182.2*210mm rectangle wafers can meet the German regulation of 2m² area limit. At present, Trina, Jinko, Tongwei, and Astrongery have already or planned to mass produce modules of the size.

Upgrading lines to produce rectangle wafers requires extra funds. Manufacturers’ pace for upgrading has become significantly slower than anticipated due to recent sluggish market. Therefore, many manufacturers have started purchasing 182.2*183.5mm and 182.2*183.75mm “near-rectangle wafers” to make 48-cell or 54-cell small format modules based on 1722/1762/1780*1134mm and 72-cll large format modules based on 2278*1134mm, which become the products during the transition from traditional 182mm square modules to large format rectangle modules. As of now, there are still various sizes of wafer and module on the solar market.

It's also worth noting that most manufacturers plan to adopt 182.2*191.6mm, G12R and G12 wafers for mass production, among which, JA Solar’s 182.2*199mm wafers can be made into 72-cell, 2465*1134mm large format modules. However, other manufacturers can also use regular 182mm square modules or near-rectangle modules to produce 78-cell, 2465*1134mm large format modules. If market demand and acceptance for such modules increase in the future, the progress of upgrading lines for 182.2*191.6mm or 182.2*210mm will be affected; some manufacturers may keep the production of near-rectangle modules for long term.

Overall, the competitiveness and demand of 166mm size have dropped markedly as production of near-rectangle and rectangle wafers gradually increases. It’s expected that market share of 166mm size will decline to around 1% and to almost none by 2027. InfoLink projects that the market share of modules based on 182mm wafer series (182.2*182.2-199mm) and 210mm series (G12R, 182.2*210mm, G12, 210*210mm) will respectively come in at 70% and 30% in 2024. Meanwhile, with market remaining sluggish, most manufacturers will continue to use 182.2*183.5mm or 182.2*183.75mm near-rectangle wafers during 2024 and 2025.

In the long run, the large rectangle wafer size will overtake near-rectangle wafer’s market share to become market trend when its development matured, which will be divided into 182.2*191.6 mm and 182.2*199mm, while G12R and G12 of 210mm series are mainly made into 66-cell and 72-cell, 2382*1134mm modules. In addition, more and more newly built capacity and planned capacity adopted G12R (182.2*210mm), allowing the 210mm series (G12R, 182.2*210mm, G12, 210*210mm) to gain market share year on year and it may even exceed the 182mm series (182.2*182.2-199mm). However, the actual development hinges on manufacturers’ mass production and end user acceptance; the trend and development of rectangle wafers remain to be monitored.