The cost competitiveness of solar PV vis-à-vis other power generation technologies is thanks in large part due to consistent technological advancements through high activity in research and development in this space all around. Beyond the recent hype of major industry players working to improve PV module efficiencies, there are several research projects that are working to bring in and bring out more innovative opportunities.
The European Union (EU) backed Horizon 2020 is a general R&D program that also supports PV technology, aimed at securing Europe's global competitiveness in PV technologies. TaiyangNews is cooperating with 4 Horizon 2020 PV projects — GoPV, HighLite, HIPERION, SUPER PV – to provide its conference platform for the projects to provide their progress on research on solar cell, module and system designs, along with manufacturing.
The purpose of our 3-day conference titled What's Hot in European Solar R&D, from June 28, 2021 to June 30, 2021, is to show how levelized cost of electricity (LCOE) of PV on the system side can be further reduced with various technological breakthroughs.
Day1 of the conference on June 28, 2021 explored new concepts for high-efficiency PV cells and modules. In their introduction for day 1, CSEM's Jacques Levrat, coordinator of the HIPERION project, and imec's Loic Tous, coordinator of the HighLite project said under Horizon 2020, there is growing research on new concepts for high-efficiency of PV cells and modules in terms of novel interconnection and improved cell design, increased module reliability, hybrid modules and other innovations – which was then explained in detail by various other presenters.
Romain Soulas of CEA-INES said the focus of the GoPV project is to reduce the cost of ownerships of HJT technology, mainly though reducing the material consumption. The presented results were referring to a 72-cell glass-glass bifacial module configuration using MBB cells of M2 size. The module also features gapless technology that reduces the BOM costs and enhances power density. So far, the GoPV project has been able to reduce the consumption of silicon by 15%, and most importantly the silver consumption, which is major cost driver of the HJT technology has been reduced by by up to 40%. The interconnection is accomplished using electrical conductive adhesives (ECA), which is also an expensive BOM. Under the framework of the project, the ECA consumption is also reduced by employing a new generation of stencil printing. With all these innovations, the 1 Euro cent per watt reduction in the cost of ownership has been achieved. In the future, the research work will focus on finding replacement of critical materials and finding silicon wafer sourcing within Europe.
Talking about the importance of packaging structures for the extended reliability/durability of silicon heterojunction (SHJ) solar modules Alessandro Virtuani of EPFL stressed that changing any one single material in bill of material (BOM) can impact the overall module performance. He further added that research conducted under the GoPV project so far has been able to record higher bifaciality for edge sealed glass-glass module structures compared to glass+backsheet versions, as the former mitigate and prevent degradation strongly. Virtuani stressed that reinforced module structures are required to have encapsulants with low WVTR or water absorption rates.
Tobias Fellmeth of Fraunhofer ISE spoke about minimizing edge losses in advanced module configurations (half cut, three cut and shingling) using high efficiency cells such as heterojunction (HJT), during his presentation. With cell sizes growing, cutting the cells is becoming inevitable. In the HighLite project, the ISE team has developed a special edge passivation technology. He emphasized that the method employed to slice the wafer has a direct impact on the benefit from the edge passivation. Instead of traditional laser cutting methods, the cleaving approaches such as TLS results in smooth edges, gaining high from the edge passivation.
Florian Buchholz of ISC Konstanz presented PolyZEBRA as the next generation low cost 3D screen-printed back contact cell. He said that the ZEBRA cell is in industrial production at SPIC in China, with ramp-up happening at Valoe's fab in Lithuania. However, there is now research on PolyZEBRA cell under HighLite project using ZEBRA cell production equipment, under which the effort is to entirely eliminate metal recombination, while aiming for an efficiency of up to 24.5% to 25%. Buchholz did add that silver reduction is still necessary to compete with PERC and achieve LCOE on utility scale. It would be ideal for specialized applications as vehicle integrated PV (VIPV).
Hybrid PV modules is the focus of the HIPERION project for which Florian Gerlich of Swiss start-up Insolight said the team aims to achieve efficiencies above 30%. By hybrid, the project means assembling the optical glass and mounting the multi-junction cells array onto a PV back plane within a standard frame. Halfway through the project, shared Gerlich, it has been able to achieve individual module efficiency of 30% and has figured out a clear path towards repeating this level with next manufacturing round.
Presenting the challenges in the power rating and design qualifications of tracking integrated hybrid CPV/PV modules in the HIPERION project, Ignacio Antón, had of the solar energy institute of the Polytecnical University Madrid (UPM) stressed on the need for amendments and to have specific research to determine failure mechanisms and appropriate tests for the same. He said, "Qualification of the design and power rating are the most necessary for the marketing of a new PV technology."
Under SUPER PV project, Robert Witteck of research institute ISFH shared some PV module innovations for reduction of LCOE, for instance the team conducted research on printing white reflectors in cell gaps, which increases light harvesting by total internal reflection and showed how increasing reflector width above cell gap improves current gain only for low ground albedo.
Panel discussion
During the panel discussion on the 'Rationale for Made in EU concepts and technologies,' TaiyangNews Managing Director Michael Schmela engaged the speakers on why Europe needs to invest in solar R&D, and if the current amount of funding is aligned with the growing demand for this power generation technology in the future.
ISC Konstanz's co-founder Radovan Kopecek felt that while Europe leads over its peers from other geographies in terms of technical know-how for instance achieving higher bifaciality, pointing out and correcting module failures, but it now needs to expand into cell production which it something it can learn from the dominating Asian competitors.
Kopecek believes while PERC is reaching its upper efficiency limits, it still makes sense for Europe to invest in this technology for its own production since that would stimulate the supply chain right from wafers and glass production. Having said that, he also added that there is a need to go beyond PERC to explore next generation technology. ISC is actually focussing on back contact cells.
Agreeing with Kopecek was Enel Green Power's (EGP) Andrea Canino, the head of their innovation lab, as he strongly argued for Europe to facilitate the development of new producers of PV supply chain. Canino was also of the view that it is important for Europe to continue to invest, and invest more in PV technology if it aims to maintain its leadership in the solar technology development. However, Enel, one of the world's larges renewable energy utilities and which focuses on high-efficiency HJT solar cells/modules in its production venture, is looking more into next gen technology research, like tandem perovskite, where Europe still has a lead. However, production processes also must become highly automated for better efficiencies, while products need to be manufactured in ways that are as sustainable as possible, something where Europe is also very good at.
Referring to learnings for the industry from COVID-19 and Europe's commitment to the Paris Agreement, Fraunhofer-ISE's Tobias Fellmeth said investing in economies of scale for cell production is a no brainer for the continent. Currently we are producing cells and modules at a higher cost, but to be able to achieve this objective, political will is a must, he said.
Laurent Coulot, CEO of Insolight, stressed Europe should be betting on new PV technologies as building integrated PV (BIPV) that give it an edge over other established technologies where it is not leading currently. It would allow the region to create a new ecosystem that's entirely independent and self-sufficient. Funding should be improved in this space, and companies too need to present their work better so as to also attract private investment from beyond Europe.
TaiyangNews conference on What's Hot in European Solar R&D will continue on June 29, 2021 with 2nd day focused on advanced manufacturing of equipment, modules, and BOS components. Its agenda is available on our website. Register free to attend remaining 2 days here.