Analysis and prediction of floating PV power plant performance

Despite the tremendous growth in the use of PV, an increased rate of deployment is needed for many years to come if we are to meet our policy goals. In the future, issues related to both land access, particularly near population centers, and intermittency are expected to become increasingly challenging for the PV industry. Another important challenge is the need to develop competitive Norwegian companies, preferably in large growth markets. In this context, floating photovoltaics (FPV) represents a truly unique opportunity to combine Norwegian excellence in industry and research in the marine, PV and hydropower sectors to create new products and business. Floating photovoltaics represents an exciting, yet immature, technology for power production with several potential advantages. Firstly, it utilizes unused areas which can be in the proximity of population centers, lowering transmission costs while not interfering with agricultural or urban use and development. Secondly, it can require less costly support structures compared to conventional, land-based PV. Thirdly, the efficiency of floating PV power plants can be improved by exploiting the colder water temperatures to cool the PV modules. Finally, floating PV is a potentially attractive solution for hybridized power plants. In this project, FLOW, we have secured access to data from five FPV systems, with three different technologies, deployed across the globe. Two of the FPV technologies are developed and patented by Norwegian companies, Ocean Sun and Current Solar. The third technology belongs to one of the greatest commercial actors within FPV, Ciel & Terre. In addition to production data it is important that the systems are well instrumented in order to study how the various environmental parameters affect the yield, and in the longer term, the reliability of the FPV systems. FLOW has contributed to instrumentation of two of these systems. Through this, it has become possible to use location-dependent production data for more general conclusions that benefit project partners and the rest of the industry. In addition to analysis of production data, we have also constructed detailed thermal models of the three FPV technologies. The thermal models provide more generic information about the yield of the technologies and hence also better energy yield assessments for future FPV systems deployed at new sites under new conditions. This is very valuable to better be able to predict the levelized cost of electricity (LCOE) and reduce the uncertainty for new investments. The thermal models and data analysis have so far provided us with concrete values of the heat transferring capabilities. For the Current Solar and Ciel et Terre technology, these results can be used directly in the important modelling software PVsyst, to provide more precise modelling of yield and LCOE. For Ocean Sun's technology, the PV modules have thermal contact with water, and water temperature therefore becomes an important factor when assessing the yield. Adaptions to PVsyst must be made in order to include this effect. Another loss mechanism that is not included in current modeling tools, and about which there is generally little knowledge, is wave-induced mismatch. During the project, we have developed a modeling tool that calculates loss percentages based on different wave conditions. The project has also included analyses of the technical potential for FPV in Europe, in addition to a techno-economic potential, calculated using the TIMES Europe model developed by IFE. In this study, we have only included lakes with clear human impact, such as regulated hydropower. The work in KPN FLOW has so far resulted in three oral presentations at one of the largest PV conferences in the world, EUPVSEC (2020, 2021 and 2023), and three posters at the same conference, one winning best poster award in 2022. The project has resulted in five accepted journal papers, and three journal paper which will be submitted by the end of 2024, several popular science articles and features on radio and in podcasts . The project joins the energy companies Equinor and Statkraft with the solar park champion Scatec Solar, Multiconsult, a consulting engineering company with a broad PV portfolio, Ocean Sun, a developer of technologies for floating PV power plants, and IFE, the leading Norwegian research group in PV technology. The project has been very important for the competence development in floating solar power at IFE and provided the basis for the Green Platform project Hydrosun. Through these two projects, IFE has taken a leading and coordinating role in research on floating solar power in Europe. This is exemplified by the fact that former project manager Josefine Selj leads the sub-task, "Performance and Reliability of FPV", within Task 13 in IEA PVPS.

Ocean Sun has actively used the project to document the performance and attract investors/customers. Multiconsult has use the results to extend and improve their ability to assist developers of floating PV technologies and power plants. For Scatec Solar, Equinor, and Statkraft the project as played an important role in increased insights for optimising the design, construction, and operation phases of floating PV plants and assessing the potential risks and gains for various aspects of floating PV. Further, much of the knowledge from the FLOW project is transferable to considerations made during planning of new ground based PV, hence the projects outcomes go beyond the scope of only floating PV. In addition to the technology specific results utilized within the project consortium, the projects have resulted in several scientific publications that is of great use for a broader domestic and international FPV industry. The project has been of great importance to IFE, who has taken a leading and coordinating role in the research on floating solar power in Europe. This is exemplified by the fact that former project manager Josefine Selj leads the task, 'Performance and Reliability of FPV', in the new Task 13 in IEA PVPS.

The field of floating solar power (f-PV) plants offers several advantages over land-based PV. f-PV has the potential to increase performance, reduce transmission and site preparation costs and to provide easy installation and deployment. The field attracts much attention both from investors, utilities and the research community. However, there is an urgent need to develop high quality data related to performance, reliability and operational characteristics of f-PV power plants for identifying innovation opportunities, reducing risks, developing improved solutions and improving bankability. That is the goal of this project, which joins the research institute IFE with the five companies Equinor, Multiconsult, Ocean Sun Scatec Solar and Statkraft, all of which are increasing their activities in the field. The primary objective of this project is to kick-start growth of a domestic industry in f-PV by developing, documenting and publishing critical, new knowledge related to the performance and degradation of f-PV and to clarify specific requirements for O&M. This will be done by reaching the following secondary objectives: • To instrument f-PV power plants in Norway and abroad for robust performance analysis. • To analyse and document performance of said f-PV power plants. • To identify and document f-PV failure and degradation modes and their propagation with time. • To quantify water cooling for different f-PV technologies and its impact on performance. • To develop verified models for water cooling for said f-PV technologies. • To develop recommendations for hybridization of f-PV power plants with hydropower. • To develop an improved understanding of O&M of f-PV power plants. • To support the education of a researcher within the field of f-PV (Nærings-PhD, already funded) . • To establish a Norwegian platform for developing further R&D and innovation projects. • To establish Norwegian researchers with a high international visibility in f-PV.