It wouldn’t be an Intersolar Europe edition of this journal without a look at a solar market closer to home; we touch on the resurgent French solar market which looks set to provide a major source of demand. As module and inverter swap outs are a growing line of work for O&M providers, we also examine the issues that emerge, such as potential induced degradation and exposing the shortcomings of projects built without adequate monitoring capabilities. TUV Rheinland presents a technical paper that could prove to be an investor’s best friend by providing a method to push energy yield performance calculations for modules beyond an extrapolation of their standard test conditions. We also introduce our new conference, PV ModuleTech, to be held in Malaysia this November, dedicated to scrutinising the technical performance claims of manufacturers and seeking out best practice.
Varying climatic conditions across markets and the individual characteristics of PV technologies undermine accurate predictions of module energy yield using conventional methods. Markus Schweiger, Werner Herrmann, Christos Monokroussos and Uwe Rau describe how a calculation of module performance ratio can be used to accurately assess the efficiency of different PV module technologies in different climates and thus the likely return on investment from a project
In this issue of Photovoltaics International Fraunhofer ISE presents a concept for a bifacial, shingled cell technology that it claims tracks a cost-effective route to a 400W module using existing industrial-scale concepts. Also one trend now much more than a notion is the ongoing switch to monocrystalline cell technology. Meanwhile the University of New South Wales pulls together and critically assesses the raft of research on perovskite PV technology. Following the success of our PV CellTech conference, we’re also introducing our new PV ModuleTech event focusing on the technology that turns completed cells into supplied modules in the commercial market.
Innovation in the field of thin-film cells, in addition to economy of scale and the manufacturing learning curve, is an important element in keeping the price of this technology competitive. Most papers on these cells focus on their technology; however, the economic potential of the technology is also important. Of even greater significance, a realistic estimation of the potential, along with the associated costs, of advanced technology, is part of the equation for profitability. Two examples of technology – metallic grids and texturing – are given in this paper; the designs are discussed, and a brief economic analysis is presented for various scenarios of the technologies. Although the profitability of these technologies can be considerable, it is shown that one should be wary of basing decisions purely on potential and on ideal scenarios, and how the cost of a technology can turn a great prospect into a trade-off.
This paper focuses on the technical progress of high-efficiency crystalline silicon solar cells and modules, specifically with regard to passivated emitter and rear cell (PERC) processes, module description and light induced degradation (LID) data. Through appropriate optimizations of the solar cell and module processes, the cell efficiency achieved in mass production is 21.3%, with module power exceeding 300W. To solve the LID problem, hydrogenation technology developed by UNSW is used, bringing the cell LID rate down to below 1%.
In this quarterly report on global PV manufacturing capacity expansion announcements we will provide a detailed analysis of 2016. Despite a significant slowdown in new announcements in the second half of the year, 2016 surpassed 2015 by around 16% to exceed a total of 55GW of thin-film, dedicated solar cell and module assembly and integrated PV expansion plans.
This paper presents a summary of the status of bifacial PV in respect of the technology in mass production, the installed PV systems, and the costs relating both to module production (cost of ownership – COO) and to electricity (levelized cost of energy – LCOE). Since the first bifacial workshop, organized by ISC Konstanz and the University of Konstanz, in 2012, many things have changed. Bifacial cells and modules have become cost effective, with installed systems now adding up to more than 120MWp and the technology becoming bankable. Large electricity providers have recognized the beauty of bifacial installations, as the lowest costs per kWh are attainable with these systems. The authors are sure that by the end of 2017, bifacial PV systems amounting to around 500MWp will have been installed, and that by 2025 this type of system will become the major technology in large ground-mounted installations.
For many applications, bifacial modules offer a cost-effective way of increasing energy yields, which explains why the interest in bifacial cells in the PV industry is steadily growing and is expected to continue. However, the metallization of bifacial cells creates new challenges, as the same materials and techniques developed for n surfaces are generally not directly, or simultaneously, applicable to p surfaces; this necessitates sequential metallization of each side, resulting in added cost and/or complexity. This paper introduces a simple co-plating approach with the objective of simplifying the metallization of bifacial cells in a cost-effective way, and which is designed for multi-wire module integration. The metallization route is described, and high cell efficiencies of up to 22.4% are demonstrated using this co-plating approach with bifacial nPERT+ cells (where ‘+’ signifies the bifacial nature of these cells). Initial thermal-cycling reliability data of test structures and 1-cell laminates is presented. Finally, cost-of-ownership (COO) estimates are given, which predict the co-plating approach to be ~40% cheaper than bifacial screen-printed metallization. It is shown that the combination of the high efficiency potential of nPERT+ cells and the reduced costs of co-plating has the potential to deliver module-level costs of ~$0.25/Wpe (glass–glass configuration).
There are numerous tools and methods available on the market for the optical and electrical quality control of high-efficiency silicon solar cells during their industrial production, and even more are discussed in the literature. This paper presents a critical review of the possibilities and limitations of these tools along the value chain, from wafer to cell, in the case of passivated emitter and rear cells, as well as a discussion of some showcases. Economic and technological challenges and future trends are addressed.
High-performance multicrystalline (HPM) silicon, achieved by nucleation on special seed layers at the crucible bottom, is now increasingly replacing conventional multicrystalline (mc) silicon, which is solidified on the standard silicon nitride coating. The HPM material is characterized by a very fine initial grain structure consisting of small, regularly shaped grains surrounded by a large number of random-angle grain boundaries. These grain structure properties, which differ significantly from those of conventional multicrystalline silicon, lead to a much lower dislocation content in the material, and therefore result in higher efficiencies of the silicon solar cells produced. This paper gives a rough overview of the worldwide R&D activities on HPM silicon in recent years, supplemented by several research results obtained at Fraunhofer IISB/THM. The focus is on the different seeding methods, the grain structure properties and the development of the grain and defect structure over the ingot height, as well as on the main challenges for further improvements in material quality and production costs.
