STC.I 2026: Bill of Materials Gains Importance As Solar Module Designs Evolve

Solar cells determine module efficiency, but a solar panel is largely built from various materials that influence cost, durability, and long-term performance. As module sizes and power ratings increase, components such as backsheets, encapsulants, glass, frames, and junction boxes are becoming as important as the cell technology itself.  

In a session titled Advancing Solar Module Performance and Reliability Through the Right Bill of Materials at the TaiyangNews Solar Technology Conference 2026 (STC.I 2026), speakers explored how material selection, evolving module designs, and local supply development affect reliability, field performance, and the competitiveness of India’s growing solar manufacturing sector. 

Bhupendra Singh Rawat, CEO of DhaSh PV Technologies, said the company has 63 GW solar junction box manufacturing capacity, calling it India’s largest component manufacturer. Referring to the policy-driven expansion of the solar PV sector – with module capacity reaching around 144 GW – he urged similar support for the ancillary industry. 

Rawat proposed creating an Approved List of Ancillary Manufacturers (ALAM) and introducing at least 20% basic customs duty (BCD) on solar junction boxes. He also suggested introducing separate HSN codes and applying customs duties to ensure fair competition, promote R&D, and support long-term sustainability. 

Rawat’s colleague, Mohammad Asif Patel, AVP Sales & Marketing, DhaSh PV Technologies, discussed the crucial role of a junction box in ensuring safe, reliable, and long-term optimal module performance. Since the junction box is exposed to harsh environmental conditions, it must withstand temperature variations, humidity, and electrical stress over decades. He emphasized that robust design, high-quality engineering plastics, IP68 protection, low forward-voltage diodes, and proper testing are essential to prevent failures. As module currents and voltages increase, junction box and diode technologies must also evolve to maintain long-term safety and reliability. 

Shifting the focus from junction boxes to another critical interconnection component, speakers from YourBuddy examined the role of PV ribbons in modern module designs. 

Rajesh Sharma and Chandan Bharadwaj, After-sales Service Engineers at YourBuddy, highlighted the importance of PV ribbons in solar modules, noting that copper PV ribbons offer advantages over conventional ribbons, especially for zero busbar (0BB) technology. They outlined the evolution from conventional busbar ribbons to multi-busbar (MBB), super multi-busbar (SMBB), and 0BB technologies.

As busbar numbers increase, ribbon specifications become finer, helping reduce shading and improve efficiency. Ultra-thin and ultra-narrow flat ribbons further improve weldability, conductivity, and mechanical strength. They emphasized that selecting high-quality ribbons is critical for achieving higher power output, long-term reliability, and cost-effective module manufacturing. 

Beyond ribbons and interconnections, the speakers also highlighted the growing importance of encapsulants and cell technologies in ensuring long-term module performance. Rajesh Singh, Group CTO of RenewSys, said the company was the first encapsulant manufacturer in India and is the only fully integrated Indian player producing modules, cells, encapsulants, and backsheets. He highlighted that while some bill of materials (BOM) components mainly impact performance and others reliability, cells and encapsulants influence both. The solar cell remains the ‘heart’ of the module, with lower degradation leading to higher lifetime energy output.   

Singh also outlined the shift from BSF to newer technologies, such as TOPCon and tandem, noting that rapid technological change creates challenges for investors. On encapsulants, he said EVA dominated early PV, but POE gained traction with TOPCon due to better moisture and PID resistance. EPE later emerged as a hybrid solution amid POE supply constraints.  

Looking at the broader picture of module performance, Parthasarathy Valivittan, General Manager – Research & Development, Waaree Energies Limited, emphasized the importance of the overall BOM. He highlighted that while solar module efficiency often gets attention, long-term reliability and low degradation are equally important.  

He underlined that BOM is the real indicator of module performance. It largely determines how well a module performs over decades. Proper material selection can keep annual degradation around 0.3–0.35%, while poor choices can raise it to 0.8%, added Valivittan. 

Key components – glass, encapsulant, cells, ribbons, junction box, backsheet, and frame – directly affect power output, resistance, moisture protection, and durability. Cost-cutting measures such as thinner glass and frames have increased failures, especially in mechanical stress and hail tests. BOM quality thus drives performance, reliability, and financial returns. For banks and insurers, material choice is a key risk factor. 

This article is part of TaiyangNews’ multi-part coverage of the TaiyangNews Solar Technology Conference India 2026 (STC.I 2026). Other sessions on Day 1 of the STC.I 2026, apart from the inaugural session, included one on module manufacturing equipment, a policy panel, and an executive panel. Day 2 also covered a market overview.  

TaiyangNews will be back with this year’s 1st Virtual Conference on Smarter Solar for Homes & Businesses on March 25, 2026. Registrations are open here.