Any business needs a monetary driver and solar PV is no exception to it. Now with the solar PV reaching grid parity, end customers/ developers/ investors are now keen to further lower its prices to maximize their commercial returns. A similar drive of cost reduction had already been realized in semiconductor where growing the size of the semiconductor chip seemed a much viable option, as it resulted in direct savings by reducing the manufacturing costs. Taking a cue from semiconductor industry, the PV industry started looking onto increasing the wafer sizes. The first major shift was from the industry settled size of M2 to M2.5 (G1) in 2018 which quickly became mainstream. Within the same time other manufacturers also started rolling out their versions of wafer sizes namely M4, M4+ & M6. Introduction of M6 in early 2019 was known to stay put as it was the practical maximum limit of expansion of the then existing cell manufacturing lines. While M6 was in the mainstream, a new wafer size M12 was introduced by end of 2019 with an idea of converging the PV industry to the semiconductor industry. It seemed that M12 was the ultimate option and there may not be any further developments, few industry players in the mid of 2020 started promoting M10 wafer (Figure 1). While there seem to be a clear distinction between these two wafer sizes, the fact that the high wafer sizes lead to higher power output modules at lower manufacturing costs cannot be ignored, which is the idea around which the current developments are encircling.

Solar project
Figure 1: The evolution of semiconductor market (on top) & PV market (on bottom) over years

With the increasing wafer sizes, it is clear that the size of modules encapsulating these cells are bound to increase which further leads to module with enhanced power output. With each and every player leaving no stones unturned to promote their module and prove their superiority when compared to other modules, it is important for us to have a comprehensive overview of advantages of such module types. For the purpose of comparison, we have considered the most prominent PV modules which are available in the market i.e. M6 based, M10 based & M12 based and M6 was considered as reference.

  • Energy yield is the amount of the energy the power plant generated for a given capacity. For a given system, it is estimated that power plant utilizing M12 based module have 1% abs gain in energy yield.
  • Better known as balance of system, BOS compiles of all the cost heads like cabling, land, MMS, inverter, etc. M12 based module are known have a clear advantage at BOS level which directly affects the CAPEX of the solar power plant. The enhancement in the energy gains and the savings at BOS level when comparing M10 v/s M12 can be attributed to the fact that by increasing the module area to around 10%, we can get power boost around 13% at same efficiency.
  • LCOE or levelized cost of electricity denotes the generating cost of energy over solar power plant’s life time. LCOE is one of the key indicators for solar plant’s overall profitability. With both energy yield of the power plant being higher and the BOS cost of power plant being lower, LCOE for M12 based power plantsis known to be better than M10 based modules.

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Figure 2: Tentative gains from various industry standard PV modules; Power plants compared at various locations, under varying conditions

From the above comparison, it is clear that module with higher power have clear advantages given that they utilize the right kind of technology. However the recently introduced modules utilizing higher wafer are still very novice and much is not known about its actual performance on field or extensive testing in labs. This preliminary makes their reliability susceptible which may in-turn lead the end customers/ financers/ investors looking onto the existing product offering of module manufacturers which are tried, tested and trusted. While much work has been done upon the mechanical designs, the module’s capacity to bear mechanical & wind loads (both static and dynamic) has been perplexing the module mounting structure (MMS) manufacturers. Further the non-standard module sizes makes the design readiness of MMS even more challenging. In addition to it, higher module sizes comes with higher weight and hence local labour guidelines need adequate considerations when installing such modules in field. At technology level, the market adaptation of M12 modules under half cell design or one-third cut cell design is still not clear. Finally with few manufacturers betting on sizes even greater than M12, the road ahead for the PV market is still hazy. This transformations however has led to many disruptive innovations which ultimately aim at cost reduction which would make solar PV more adaptable. While new modules post newer unseen challenges, the industry would cumulatively find a way out.

Let us all pledge to make solar energy the primary source of energy in the near future.


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