Abstract
Aim and approach. Aim of this study is to verify the environmental sustainability of several Building Integrated Photovoltaic (BIPV) systems, considering their whole lifecycle. More in detail, 4 types of BIPV products are here analysed: windows, roof tiles, façades, transparent solar glass. This work is part of the Horizon Europe (HE) project MC2.0 , which aims to develop a “mass customized” production line for BIPVs. The Life Cycle Assessment (LCA) methodology is applied here to evaluate several impact categories, with primary focus on climate change, by determining lifecycle greenhouse gas (GHG) emissions. Other impact categories, together with a material criticality and energetic consumption evaluation, are evaluated in a second step. The outcome of this study serves as an ex-ante guide towards the choice of the most eco-friendly processes and materials to be used in the early design phase of new BIPV solutions. Scientific innovation and relevance. It is well known how solar electricity can contribute to GHG emissions reduction: 1 kWh of PV electricity emits about 50 gCO2-eq, compared to 450 with natural gas electricity . Despite that, it becomes relevant to enrich literature with studies that are tailored to BIPVs, as they involve new manufacturing processes. In fact, they combine several functions in one product, compared to conventional PV having just the function of producing electricity. The LCA method used is already well established for the electricity and the building sector, but much fewer studies apply it to BIPVs. The innovation in this analysis lies in the use of real primary industrial data, thanks to the support of MC2.0 project partners. Two types of cells are analysed: the traditional rigid crystalline silicon (c-Si), and the thin film flexible CIGS cell. The inventories related to CIGS cells and their integration in solar roof tiles were provided by M. Theelen et al. (see abstract “A comparison of the environmental impact of integrated flexible CIGS with rigid CIGS and x-Si modules”), while inventories for the other BIPV products (window, transparent glass, façade) were collected by Eurac. Results and Conclusions. Through our study, we can quantify the reduction in GHG emissions achieved by utilizing electricity generated from BIPV instead of the conventional grid-supplied electricity. As an example, by installing on a German building 1m2 of BIPV roof tiles made with c-Si cells, it is possible to save about 610 kgCO2-eq over the full lifetime of the BIPV, thanks to the use of solar energy instead of the German grid mix. This result was obtained considering the decarbonization trend for the future German grid mix. As a simple conclusion, it can be confirmed that, despite their overall lower efficiency, BIPVs can actually make a significant contribution to the decarbonization of the building sector.