BiPV in a multicriteria assesment of building envelope solutions. Considerations on economic aspects

The increasing demand of Nearly Zero Energy Buildings (NZEBs) is rapidly contributing to change the building envelope from a passive barrier towards an adaptive and sensible skin. The Building Integrated Photovoltaic (BiPV) involves two main topics: construction technology and architecture. One of the key aspects is the multi-functionality: PV becomes a constructive part of the building envelope that cannot be just considered as a single plant since it strongly characterize architecture, technology, energy behavior and costs. Despite in literature many examples show the high potential of PV integration in buildings, the complexity of the involved requirements do not always suggest the BiPV as an easy option in the early design phase. Consequently PV is often postponed to a later stage of the construction to simply be adapted onto the building with the cheapest option. Purpose of the work, starting from a multicriteria approach, is to give a contribution concerning the economic assessment of BiPV, through the evaluation of costs and benefits in a life-cycle perspective. Results allow to appreciate the essential role of PV in the building envelope design confirming that in some cases BiPV is a cost-effective opportunity so that the economic worth joins the quality of the building