By Nicola Licata

This article was originally published in pv magazine – February 2024 edition.

The need for greater supply chain traceability has pushed the PV industry to adapt, with new procedures to support documentation at each stage of manufacturing. Nicola Licata, of Clean Energy Associates (CEA), explains how evolving processes are preparing the PV industry to face future challenges. 

Over the past 18 months, the solar industry has faced a critical transition to new US trade regulations. The Uyghur Forced Labor Prevention Act (UFLPA) requires traceability documentation to verify silica-based solar panel supply chain maps, from quartz origins to final assembly. Solar industry traceability measurably improved in 2023, according to CEA’s experience conducting documentary and on-site traceability audits across module, cell, wafer, and ingot suppliers. The challenge with PV supply chains centers on the diverse client base. For manufacturers, complying with different laws for different export markets creates complexities in material differentiation.

Target markets

Labeling for specific sales markets has had a big impact on upstream solar manufacturing. It is easy for each supply chain partner to implement a two-digit code, such as “NA” for North American clients, in its records, maintaining observable linkages through operations. This has maximum effect when a label is visible in supplier purchase orders, warehouse records, physical segregation markings, manufacturing execution system (MES) records, work order forms, process cards, and packing labels. Early differentiation enables two-way traceability – from upstream raw material sources to module assembly, and vice versa. It helps suppliers move away from the traditional method of linking materials to clients only at module assembly. Suppliers can then provide a more thorough and timely assessment of the materials used, providing buyers with greater confidence in the traceability and integrity of their products. Contractual agreements between suppliers and buyers are essential for early differentiation and multidirectional audit access. US-based clients should treat traceability as a vital component of the supplier-buyer relationship, as it is a special request rather than an industry standard or license to operate.

Support system

When compiling traceability documentation for government agencies, it is imperative for suppliers to tell their supply chain story well. MES are integral to linking disparate pieces of equipment in a factory, ensuring a comprehensive chain of custody and seamless flow of information. An MES can record the smallest possible production units, whether 10 kg bags of polysilicon, ingots, wafer packs, cell boxes, or modules. Scanning barcodes at each machine along the production line enables automatic, real-time records to be aggregated in an MES and ensure chain of custody. Factories without an MES can control quality but carry more relative risk in terms of ensuring traceability. Even some of the biggest vertically integrated PV suppliers did not have MES across their full supply chains when United States traceability requirements came into effect, in June 2022. Different nodes were supported by different IT databases with varying capabilities. That is now changing as plans to install systems are taking shape. Increased MES implementation is a notable improvement. It has required financial and operational investment, particularly retrofitting older factories to ensure IT interoperability. Despite these challenges, successful programs to purchase, install, and ramp up MES have led to observable improvements in tracking the smallest units of raw materials as they transform along the production floor – as well as in the document provision required to meet traceability requirements by buyers, financiers, and asset managers alike.

The changes in recycling traceability practices also have positive implications for material handling and storage.

— Nicola Licata

Recycling traceability

Ingot workshops, where polysilicon is processed into crystal form, represent a critical stage in the photovoltaic manufacturing process. Around 20% of each cylindrical ingot crystal is trimmed off during production, leaving behind materials that are then recycled for reuse. Previously, the tracking and labelling for this recycling process was vague, creating the risk of material being mixed into different work orders. Improved recycling procedures and distinct labeling systems are increasingly coming into effect, and these mark another significant advancement. These new systems, reflected in both physical labels and MES data records, provide clearer differentiation between raw, new polysilicon and recycled materials – a crucial distinction for maintaining traceability as these materials move through production. The changes in recycling traceability practices also have positive implications for material handling and storage. Workshops are now implementing segregated storage areas for different types of materials, ensuring a clear physical distinction between new and recycled polysilicon. This segregation is best when complemented by detailed labeling, which includes information on material type, time of processing, quantity, and project affiliation. Integrating these detailed recycling records into an MES further enhances the traceability of materials, providing a more complete picture of those used in each module, for overall integrity and compliance with supply chain requirements. The emphasis on detailed recycling traceability represents a commitment to transparency and accountability in the industry.

Well positioned

The year 2023 was a turning point for the solar industry and its approach to traceability. The advancements made in product differentiation, MES utilization, and recycling traceability in ingot workshops were a significant evolution in industry practices. These changes are the result of the industry’s proactive adaptation to regulatory requirements and its commitment to maintaining a transparent and compliant supply chain. The ongoing investment in new tech and different approaches to vertical integration position the industry well for future developments and challenges in solar energy production and distribution.

Nicola Licata is a senior environmental, social, and corporate governance and traceability project manager at CEA, based in Shanghai. She has contributed to 35 documentary and 22 on-site chain-of-custody audits for PV suppliers in China, Thailand, Vietnam, and Malaysia. She looks forward to on-site audits at polysilicon factories in the first half of 2024.