Multi-dimensional evaluation of BIPV installations: Development of a tool to assess the performance as building component and electricity generator

The demand for building-integrated photovoltaics is constantly increasing, which is reflected in an increasing number of innovative BIPV products on the market and attractively implemented BIPV installations. To support architects, system developers, and other stakeholders involved in the planning of new BIPV projects, the experts of IEA-PVPS Task 15 have developed a multi-dimensional assessment tool based on the experiences and learnings of already installed BIPV-projects. The creation of a comprehensive, interdisciplinary evaluation methodology makes it possible to compare the multi-dimensional performance of existing BIPV systems, to derive strengths and weaknesses and to use this knowledge to plan application-optimized new BIPV systems. In a systematic step-by-step development process, four performance categories were defined: energy-related, economic, environmental and optical/visual. After defining the relevant performance indicators per category, a numerical rating system was established. In addition, a classification scheme for all relevant BIPV installation types was defined. Initial analyses were performed by a group of experts on several case studies of BIPV-roofs, facades and external devices in order to test and validate the methodology and approaches. Multiple iterations were required to optimize the methodology, as issues such as (i) lack of data availability for full project assessment or (ii) objectivity in visual assessments exist and will remain demanding. The research work also identified challenges and limitations in the context of pioneering and pilot building-integrated photovoltaics (BIPV) projects, which often used newly developed, immature or early-stage technologies at the time of their construction. The evaluation results of such lighthouse projects can vary significantly from those of BIPV installations using standardized products and well-established processes.