Trina Solar explains latest joint effort to standardize silicon wafer, solar module sizes

standard sizes trina solar

The 210mm size silicon wafer and module size standardization proposition is an attempt to standardize the entire industry chain, including module products.

Solar module manufacturers are pushing the limits of panel size to chase higher wattages and product differentiation, but these variations have downstream and upstream consequences. To close out 2020, Trina Solar Co. and seven other companies jointly proposed / promoted a standard size spec for silicon wafers and the resulting solar modules. The goals are to achieve the best possible scale, and empower all businesses to improve production efficiency, optimize supply, reduce the cost and drive technological innovation.

The eight companies (Trina Solar, Risen Energy, Zhonghuan Semiconductor, Tongwei, Huansheng Photovoltaic, Runyang New Energy Technology, Canadian Solar, Wuxi Shangji Automation) jointly suggest to use the silicon wafer size following the SEMI standard within the 210-220mm size range: 210+/-0.25mm as the only size. And at the same time revise the SEMI and existing modules size in PV industry association according to the wafer size.

Important note: The 210mm size silicon wafer and module size standardization proposition is an attempt to standardize the entire industry chain, including module products. This initiative is not only from the perspective of the industry chain, but also from the standpoints of the users. The standardization of the 182 mm size first appeared in June, but only for the silicon wafer size — the module size was not considered.  This time, the 210-camp represented by Trina Solar proposed the standardization of the 210-size, including the specifications and recommendations for the size of silicon wafers and module design (whether double-glazed modules or backplane modules).

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Why this size? The benefits of large-size of silicon wafer cells and high-power modules include flux value, dumpling effect, and the cost savings of the number of blocks that drive the cost reduction of large-size silicon wafers, cells, modules, and BOS.

  • Flux value refers to the increase in production capacity brought about by large-size products, thereby reducing the cost of labor, depreciation, and three types of expenses per unit of output;
  • the dumpling effect refers to during the use of large-size silicon wafers to produce modules, the increase in the amount of auxiliary materials such as the frame, glass, backplane, EVA, ribbon bus bars, pallets and packaging materials in transportation is less than the increase in the area of the modules, which brings about savings in module encapsulation and transportation costs;
  • cost savings related to the number of blocks refers to during the process of module production and power station construction process, the costs of junction box, potting, combiner box, DC cable, installation and construction are only related to the number of modules, so the use of large-size products will increase module area and power, which decreases the costs of module production per watt and power station construction significantly.

Cost reduction effect

trina solar value chain

Through the standardization of 210mm size silicon wafer, the size of the silicon wafer and module etc., Trina says the industrial chain can achieve the best scale effect, powerfully help upstream and downstream enterprises improve production efficiency, optimize supply, and drive industry technological innovation, while reducing the cost of industry chain manufacturing, the initial investment of photovoltaic systems and LCOE (levelized cost of energy) of power generation, to achieve grid parity.

Design: The unified module size reduces the uncertainty in the design process, and improves the efficiency while selecting racking structure, inverters, cables, combiner boxes, etc. and enhances the flexibility of module supply. At the same time, the installation efficiency of modules and racking structure can be improved, and the design and EPC costs can be reduced. It can be seen that the unified module size standard is the gospel of customers.

Flexibility: After the size is standardized, when the investor has multiple power stations under construction, and the supply of modules cannot be ensured, there will be greater supply flexibility. The owner can have flexible deployment between projects or between each bidding section of a project according to the degree of project tension, without affecting the grid connection of the owner’s project.

Mounting: The standardized size can ensure the consistency of the mounting holes during the racking structure design, effectively speeding up the design and processing progress of the racking structure, and providing a guarantee for the rapid advancement of the owner’s project. Therefore the versatility of the racking structure is improved. When the project capacity has to be reduced due to external reasons, the racking structure purchased by the owner will not be wasted and can also be used for other projects.

Inverters and optimization: The significance of standardization is also reflected in the design of inverters, racking structure and trackers, and the financialization of optical power storage. The extreme cost reduction of the photovoltaic industry and the increase in the competitiveness of the price of solar storage power per kilowatt-hour will inevitably be accompanied by “standardization” for a long time. Based on the significant advantages of the 600W+ ultra-high power module system, the standardized module size will bring more long-term value to customers in the design of downstream power stations.

Supply chain: From the perspective of the supply chain, standardization is beneficial to improve the stability of the supply chain and reduce the cost of the industrial chain. The upstream and auxiliary material suppliers such as glass, silicon wafers, junction boxes, etc. are produced under unified standards, which will greatly reduce the loss caused by switching production lines and the inventory cost due to different specifications, so that the production of the 210 mm size modules’ entire industry chain will be more ordered and effective.

The diversification of photovoltaic module sizes not only led to the low matching degree in supply chains, but also added a lot of direct and hidden costs. Many glass manufacturers and modules manufacturers have also put forward their demands for uniform specifications as much as possible. When the glass supply gets tight, the industry still loses more than one million square meters of glass production capacity every month due to the switch of different sizes of product specifications; and hundreds of thousands of square meters of glass have become stranded inventory due to the cancellation of customer orders. Not only that, due to the diversification of the size of photovoltaic modules, glass manufacturers need to stock a variety of specifications of glass, these glasses cannot be used between different module factories, bringing a lot of inventory costs to glass companies, affecting the supply capacity and delivery in time. After the standardization of size, the inventory and supply of glass and all modules related to the size and specifications of the backplane, EVA, junction box and other non-silicon auxiliary materials can be optimized.

The cost reduction effect of “standardization” is not only reflected in the optimization of module material inventory and supply, but also in the production and manufacturing process of the overall industrial chain, including silicon wafer pulling, slicing, cell manufacturing and module manufacturing. Even if the manufacturing equipment is compatible, different tooling and fixtures must be configured to meet different cell or module sizes (tooling cost is estimated at 5-7 million RMB/GW). The greater impact is on the loss of production capacity when switching between products of different, inventory costs of products of different specifications, and processing costs of downgraded products. According to preliminary estimates by industry insiders, it usually takes 10-12 hours to switch between different products in cell and module manufacturing. In addition to the loss of yield and efficiency per switch, the cost of each switch is about 0.003-0.005¥/W, with its 1GW correspondent cost of 3-5 million¥/run.

With the standardization of large size silicon wafers, solar cells, and module sizes, the industry chain will achieve a better scale effect, improve production efficiency, and reduce the cost of industrial chain manufacturing, photovoltaic system initial investment and LCOE of power generation. Through the unification of standards, the entire industry chain will work together to create higher-quality photovoltaic products, bring higher value to customers, and reduce the LCOE of power generation. This standardization initiative is of great significance to the photovoltaic industry and will lead the industry to a new level.

— Solar Builder magazine


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