IBC achieves >26% efficiency with up to 44% silver reduction and is close to industrial feasibility, with >90% TOPCon line compatibility
BC enables premium niche applications, delivering >20% additional power than PERC in BIPV formats with added design flexibility and aesthetics
BC is industrially viable using existing PERC infrastructure, but yield sensitivity and additional process steps remain key scale-up challenges
BC module cost premium has narrowed to ~20%, making it viable for niche markets, but policy gaps and limited EU-wide participation constrain scale-up
Solar manufacturing is rapidly becoming a strategic priority for nations worldwide. Producing locally is now about more than just economics; it is a matter of resilience and energy security. The recent fossil fuel crisis has underscored this point. In this context, if regions like Europe are serious about reducing dependencies, strengthening domestic manufacturing capacity is essential to meet at least some part of the demand. And that is what Europe is aiming for. This becomes even more important when breakthrough technologies can be developed at home. Instead of simply licensing technology, it is far better to own it and build it up locally. That’s exactly where the IBC4EU project comes in.
Over the past 3.5 years, the project has worked across the full value chain, from wafers to cells and modules, to demonstrate that high-efficiency, low-silver Back Contact (BC) technology can be developed and scaled in Europe. The project spans the full value chain, integrating research institutes, equipment suppliers, and industry players to validate processes under realistic conditions. As the project has reached its conclusion phase, TaiyangNews co-hosted a webinar High in Efficiency, Low In Silver: Back Contact Technology From Europe with ISC Konstanz and WIP Renewable Energies to highlight the key findings of the initiative.
BC Tops in Efficiency
In his welcome talk, TaiyangNews Managing Director Michael Schmela took the TaiyangNews TOP SOLAR MODULES feature as the lead, which lists the top commercial module efficiencies from leading integrated suppliers. BC has been leading the charts since the early days of this feature, about 4 years ago. While the top efficiency level of TOP SOLAR MODULES during the webinar was 24.8%, it has since reached a new benchmark of 25%.
Florian Buchholz, Director at the leading German research institute ISC Konstanz, summarized the specifics of the project. IBC4EU, with over €17 million in funding from Horizon Europe, has now completed its 42-month duration. The goal of the project was to implement a virtual pilot manufacturing line with all partners involved.
BC Development Potential
The project confirms that both p-type and n-type wafers can be developed into IBC cells, with p-type POLO-based IBC exceeding 25.5% efficiency and n-type polyZEBRA IBC surpassing 26%.
At the cell level, metallization improvements reduced recombination losses, while refinements in passivation and firing profiles helped recover voltage and push efficiencies beyond 25%. Efforts to reduce silver progressed from replacing silver with silver-coated copper first for busbar and then also for fingers. Buchholz presented reference results from using silver fingers in combination with copper busbars, achieving cell efficiencies of 24.3% and reducing silver consumption by 44%. Tuning of the breakdown voltage helped improve the partial shading behavior.
The industrial feasibility of TBC was also evaluated. Laser-based, mask-free processes were used for structuring, along with screen-printing metallization using Ag/Cu based pastes. It was found that more than 90% of an existing TOPCon production line, with some modifications, can be adapted for TBC manufacturing. However, some challenges remain, including maximizing Voc and tight tolerances for laser processes. Compared to a standard TOPCon line, TBC requires 4 to 5 additional steps, which may lead to a yield penalty of around 1 to 1.5%, with higher losses expected during early ramp-up. Despite this, TBC is considered close to industrial feasibility.
At the module level, full-size modules using M6 half cells with copper busbars have already been demonstrated. Gapless designs using cell-to-cell overlap were implemented. Overall, the feasibility has been proven at pilot scale, and the technology is ready for mass production trials, underscored Buchholz.
Made-in-Europe BC for BIPV
Skirmantė Baležentienė, CEO of Metsolar, a company specializing in custom PV solutions, represented the applications front of the technology. She presented the industry and market perspective for Made-in-Europe BC modules, with a focus on BIPV. She introduced Metsolar’s portfolio spanning BIPV, rooftops, façades, skylights, and agrivoltaics. She highlighted the company’s shift toward customized solutions that align with modern building materials and smart-city requirements. Alongside conventional glass-to-glass and lightweight designs, Metsolar is also offering products such as Kovas Tile, Laume Roof, and Skin+ façade, offering enhanced aesthetics through varied colors and wooden backplate mounting.
A comparative case study of the Laume Roof series showed that BC modules deliver over 20% higher power than PERC modules of the same size. In addition, the overlapped cell interconnection further improves visual appeal. For VIPV applications, Metsolar’s latest lightweight BIPV modules achieve more than 15% higher power than conventional PERC alternatives, according to Baležentienė. In agrivoltaics, the company’s modules provide transparency levels of up to 70%, underscoring the adaptability of BC technology across specialized applications.
Production Feasibility of BC
Bringing in the manufacturer’s perspective, Kalyon PV discussed scaling of BC technology from lab to fab. Özlem Coşkun, R&D Executive – PV Technologies and Applications, noted that scaling IBC technology from lab to fab requires more than achieving high efficiencies, as it also requires industrial validation at every stage. As a fully integrated ingot-to-module manufacturer, the company leverages its production ecosystem to test new concepts under real manufacturing conditions. The company has successfully transformed its production from PERC to TOPCon and then to larger wafer formats such as G12R. Its ongoing R&D concentrates on high-efficiency pathways such as BC, advanced passivation, and tandem architectures.
Within the IBC4EU framework, Kalyon PV contributed across the spectrum, from gallium-doped CZ wafer development to module-level testing. The company identified an optimal wafer resistivity range of 1-2 Ω·cm for POLO IBC and achieved carrier lifetimes of up to 3 ms. In parallel, wafer thickness was reduced from 175 µm to 130 µm using optimized slicing and tungsten-diamond wire, enhancing material utilization while maintaining mechanical integrity.
On the cell and module side, Kalyon PV demonstrated that POLO IBC processing can be adapted to industrial p-type wafers through optimized texturing, cleaning, and passivation. The company developed M10-format designs and conducted outdoor testing in Ankara, benchmarking IBC modules against reference PERC modules under real operating conditions. The results indicate that industrial tools can closely approach lab-level performance. However, the technology is not without its trade-offs: using thinner wafers increases yield sensitivity, and additional process steps vis-à-vis PERC can affect throughput, said Coşkun. Despite these challenges, the process remains largely compatible with existing PERC production lines with only limited equipment additions.
Philippe Macé of the Becquerel Institute presented a concise overview of Europe’s PV market, policy landscape, and the outlook for BC technology. He observed that after nearly 2 years of steady decline, imported module spot prices have recovered slightly over the last 6 months. This change is linked to factors such as inventory clearance, reduced Chinese production, policy changes, geopolitical risks, and rising fuel prices. The IBC4EU project findings show that the cost premium for IBC modules has decreased to about 20%. Although still above mainstream technologies, such premiums are deemed acceptable in niche markets like BIPV, AgriPV, and IIPV, as long as these markets continue to grow through 2050, Macé noted.
On policy matters, Macé pointed to important initiatives such as the Net-Zero Industry Act (NZIA) and the Innovation Fund Auction (IAA). The NZIA aims for up to 40% of products to be made in Europe. Several European countries, such as France, Italy, Austria, Germany, and Spain, are either working on or implementing supportive policies. However, challenges persist, including low participation across EU nations, uncertainties about IAA implementation timelines due to trade agreements, and gaps in policy coverage, particularly concerning module manufacturing. Capacity limits under NZIA also hinder scaling efforts. Despite these issues, Macé concluded with suggestions to strengthen Europe’s manufacturing capacity and foster a more competitive environment for BC and other advanced PV technologies.
The panel discussion addressed a central question: how BC technology fits into Europe’s manufacturing future. Moderated by TaiyangNews’ Schmela, the session opened with a discussion of the role of funded research initiatives such as IBC4EU under the Horizon framework, particularly given Europe’s relatively limited manufacturing base. Panelists unanimously agreed that such programs are critical. ISC’s Buchholz noted that these projects ensure technologies are industrially ready when market conditions align. Baležentienė from Metsolar emphasized that continuous innovation remains the key differentiator for European manufacturers. She pointed out that manufacturers need to innovate faster than they are being copied to stay competitive. While Europe still has a strong technological base and some manufacturing presence, sustaining this position requires continuous, rapid innovation, which is facilitated by such funded research projects. From an industrial standpoint, Kalyon’s Coşkun highlighted that research must be complemented by pilot-scale validation and early production to bridge the gap between lab results and large-scale manufacturing – an approach embedded within the IBC4EU framework.
On the manufacturing pathway, Becquerel’s Macé pointed out that while TOPCon can sustain current production, BC technology offers stronger long-term differentiation. However, Europe is likely to rebuild its manufacturing base, starting with modules, with cell production following as scale and confidence grow. The discussion also touched on tandem technologies, where Europe holds strong R&D capabilities, but commercialization remains several years away. In contrast, BC is viewed as a nearer-term opportunity. On the supply side, Baležentienė noted that BC cells remain less readily available and command a premium, necessitating better planning and tighter quality control than PERC or TOPCon.
Reliability and application scope were also points of discussion. While existing BC products are generally reliable, some claimed advantages, such as shading performance, remain challenging to fully realize in practice. Demand in Europe is currently concentrated in residential and C&I markets, though this could evolve with improvements in bifacial performance.
The panel also discussed BC’s role in the utility-scale segment. Macé noted that current demand in Europe is driven mainly by residential and C&I applications, with limited presence in utility-scale. However, this could change if bifacial performance improves. Buchholz added that front-side efficiency has a stronger impact on energy yield and noted that BC modules have already reached around 80% bifaciality. It was also suggested that some manufacturers may position BC as a premium product due to limited margins in mainstream modules.
Policy uncertainties, particularly around the NZIA and IAA, were flagged as constraints due to delayed implementation and limited scope. In conclusion, the panel underscored the need for coordinated momentum across industry, policymakers, and research institutions to strengthen Europe’s domestic manufacturing capabilities. As Baležentienė aptly concluded, the industry should aim to ‘make back contact great’.