Doris Österreicher

The European Union has set itself the goal of increasing its share in renewable energy up to 42.5% by 2030 by accelerating the clean energy transition plan. National legislation within the Member States must now adapt the strategic plans to rapidly implement their allocation in renewable energy. Solar photovoltaics are in this context considered to be one of the technologies that could rapidly be rolled out, with both building-integrated as well as free-field photovoltaic systems needed to reach these ambitious goals. There are strong arguments for prioritizing photovoltaics on buildings, as they make use of land that is already sealed, and the environmental impact is considered lower as fewer resources might be needed for the structures holding the panels. However, since there is limited literature available to back this claim with quantitative data, this paper presents a comparative study of the structures needed to implement rooftop versus free-field photovoltaic applications. With a detailed life cycle analysis, several commonly used structures have been analyzed in relation to their environmental impact. The findings show that the impact on resources can be up to 50% lower in rooftop systems compared with free-field applications but that a series of site- and material-related factors need to be considered to prioritize one system over another on a regional scale. This study thus aims at providing fact-based decision support for strategic considerations related to photovoltaic implementation plans.