CP.1,
Manufacturing

CP.2,
PV Everywhere & Performance and Reliability

CP.3,
Thin Films and Tandems

Today we continue with a preview of the plenary talks scheduled for Wednesday, 25th September.
The morning will feature two sessions: one from 8:30 to 10:00 titled “PV Everywhere”, and the second from 10:30 to 12:30, which encompasses two topics. The first three presentations are under the title “Performance and Reliability”, and another three under the title “Thin Films and Tandems”.

The Session title “PV Everywhere” already points to the scope of the next four plenaries, which will be about three promising ways to utilise existing space for PV generation: Agrivoltaics, Building Integration, and floating PV.

We start with an exciting introduction in the field of Agrivoltaics. We invited the French company Sun’Agri which has been commercialising professional tracking systems optimised for controlled shadowing of agricultural plants for the past five years. In the presentation 4CP.1.1 “Dynamic Agrivoltaics: An Agronomical tool to Protect Crops from Climate Change”, the focus will be on the agricultural benefits of such systems, by controlled shadowing in very sunny fields: soil retention, water collection, reduction of evaporation for instance. Sun’Agri certainly hasthe experience to optimise these benefits, and the plenary talk seems to be of interests to PV experts who thought that Agrivoltaics is just another land-grabbing idea. In fact, a project of Sun’Agri recently faced resistance from the local population, and we hope that the presentation gives insight into how such conflicts can be resolved.

The second plenary highlights the huge potential of applying PV in agriculture. In the presentation 5CP.1.2, titled “The Potential of Agrivoltaics in the EU’s Green Deal”, the European Commission’s JRC assesses the feasible potential of Agrivoltaics in the EU through an advanced geospatial analysis. As Agrivoltaics combines food and energy production on the same land, factors such as land use, biodiversity, and distance to the electricity grid are key. Moreover, the identification of suitable areas for agrivoltaic systems based on specific requirements, such as the exclusion of protected areas, distance from industrial and settlement areas, and proximity to transport infrastructure. The JRC's Photovoltaic Geographical Information System (PVGIS) is used for much of the analysis. An interesting aspect will be the author’s comparison to the requirements set out in national agrivoltaic guidelines published in some EU countries. We should get a very good picture of the future of Agrivoltaics in Europe.

The Integration of PV into the building skin has been a challenge for more than 40 years. Very often, local regulations require a match of the colour or structure of PV modules with the material of the building. The presentation 4CP.1.3 “Coloring Solutions for Building Integrated Photovoltaic Modules: A Review”, by EPFL will provide a comprehensive review of today’s technologies and their implications for the integration of solar energy into the built environment. The outstanding feature of this presentation will certainly be a review of the recent remarkable advances in processing the PV module front surface, including patterning and structuring. You can also expect to being briefed about additional costs and in particular, the stability and reliability of the different colouring technologies.

You will agree that the word “trouble” in the title of the presentation 4CP.1.4 “Five Years of Trouble: Learnings from Floating Solar Field Testing in Challenging Conditions” raises some curiosity. This plenary talk will be about the learnings and observations from field testing floating solar installations in challenging conditions, including mechanical and electrical issues encountered, as well as observations on soiling, underwater growth, and thermal behaviour and many others. The presenters are from the Dutch research organisation TNO, in a country that has always found solutions when it came to fighting against the sea. As the authors have been studying floating solar plants also in offshore locations, we can certainly look forward to some spectacular pictures and videos!

Regarding Performance and Reliability, this session features two presentations typical for today’s quality assurance systems, and a third on developments to increase the performance of partially shaded modules.

In the first invited plenary of the session 3CP.2.1, titled “Quality Assurance of materials for long life-time (DuraMat initiative)”, we will be briefed by NREL on the outcome of the US initiative to significantly increase the lifetime of PV modules. This project is designed to accelerate the development and deployment of durable, high-performance materials for photovoltaic (PV) modules to lower the cost of electricity by increasing field lifetime. This Durable Module Materials (DuraMat) consortium recently released a report that, among other interesting results, announces a new tool to forecast PV module performance over its lifetime. We are sure to get first-hand and detailed information from the authors about the tool and new materials in this plenary.

Given that Australia has extensive experience with large scale PV systems deployed in a harsh and hot environment, we invited a plenary talk CP.2.2, titled “Quality Assessment of Large Scale PV Systems Using Daylight Photoluminescence Imaging”. What the title does not mention is that the group from UNSW in Sydney is using installed, commercial inverters to set an operating point to the arrays in a way that allows photoluminescence which can occur on faulty modules. The method does not require special equipment to be connected to the array. An off-the-shelf camera drone compares images at two different setpoints of the inverter and rapidly indicates faulty modules. We believe we will all have some surprises when viewing this innovative work for a cheap, easy-to-use inspection method.

In the plenary 4CP.2.3 with the title “Performance of Partial Shaded PV Generators Operated by Optimized Power Electronics Review of an IEA PVPS T13 Activity”, we expect a comprehensive insight into the problem of partially shaded PV modules. This issue arises in classical PV fields at low solar angles, but also from shadows casted by chimneys, satellite dishes or nearby trees in roof-mounted PV systems. The market has developed “Module Level Power Electronics (MLPE)” to avoid significant power losses (which are often higher than the loss by the shadow itself!). An international team of experienced PV experts are gathered within the IEA PVPS T13 consortium in a fact-finding mission to bring light into the shadow of promised performance gains of MLPE. Within this IEA PV Power Systems consortium, several labs analysed the gain in performance of partially shaded PV generators when operated together with optimised power electronics, devices that are often advertised with unrealistic power gains. The report on the results will likely be published only after the EU PVSEC, making this plenary a valuable occasion to gain knowledgeable insights into the results, in particular into the economic benefits or drawbacks of MLPEs.

For the past ten years, the efficiency race of Perovskite-based solar cells has been one of the more recent and exciting technology stories of PV. The plenary 2CP.3.4 titled “Perovskite PV Outdoors: From Single-Junction Single Cells to Mini-Modules and Tandems”, addresses the issues beyond the high efficiency records. Do these cells and modules live long enough in a real outdoor environment? The presentation will explain the various degradation pathways, which are different for the variety of device structures. Single-junction Perovskites already feature different degradation rates than tandem and heterojunction structures. The devices have been tested in climatic chambers, however, the combined stress in an outdoor environment creates different exposure failures. If you want to profit from the knowledge of the authors from a consortia lead by HZB, about how long it will take until Perovskite-based solar cells will substitute our “conventional Si-PV modules, you will have an excellent opportunity to judge the facts when listening to this talk.

The following plenary is a must for everyone who wants to learn how European projects aim to take the lead in the global race to commercialise Perovskite-based solar cells. The plenary 2CP.3.5 “Perovskite/Silicon Triple Junction Devices: An Overview of the Progress and Results From the TRIUMPH Project Funded Under Horizon Europe”, will provide detailed information on current development of cost-effective and highly efficient perovskite/silicon triple junction solar cells. The TRIUMPH project, which aims to develop cost-effective and highly efficient perovskite/silicon triple junction solar cells, has the very ambitious target of achieving 33% conversion efficiency for triple junction Perovskite-Perovskite-Silicon solar cells. The very first lab prototypes already exhibit up to 23%, and special adjusted solar simulators are needed to verify the measurements. All in all, it is a remarkable European project that still has some way to go, but don’t miss the presentation of the early results achieved already.

To complete our view on thin-film technologies, we invited a presentation about chalcopyrites, or more precisely, CIGS cells. In the plenary 2CP.3.6 titled “CIGS – Excellent by itself and in Tandem”, the author from the University of Luxemburg will report on recent new record efficiencies for mono- and bifacial chalcopyrite solar cells. One factor contributing to this record efficiency was adding Ag and optimising the composition gradient. The presenter will also discuss the latest progress in chalcopyrite-perovskite tandem cells, as well as the perspectives for all chalcopyrite tandem cells. You see, the “Materials Zoo” for solar cells is as lively as ever, and you should not miss it!

This concludes the preview of the two plenary sessions on Wednesday. Take a comfortable seat in the main auditorium and enjoy a full morning of excellent presentations!

Plenary Summary by
Heinz Ossenbrink
Former European Commission Joint Research Centre