Attractiveness of Using Photovoltaic Panels in a Building Connected to a Mainly Renewable Electricity Grid

Abstract

Photovoltaic (PV) panels contribute to overall building's loads, but generally have their impacts offset at the operational stage. For increasingly renewable electricity grids, PV's contribution to lowering non-renewable energy becomes less significant. This paper aims at investigating the non-renewable cumulative energy demand (CEDnren) and global warming potential (GWP) payback times associated to onsite PV generation in the highly renewable Brazilian grid, considering a 50-year building service life. Operational energy consumption was simulated in Energy Plus. CEDnren and GWP were calculated through the CED method and CML-IA, respectively. SimaPro 7.3 and Ecoinvent 2.2 supported performed LCAs. Different PV settings were analyzed to rank the most effective technological options. Amorphous and single-Si panels performed worst (around 17 years of non-renewable CED payback time, whilst for GWP the payback time was much shorter for all technologies). PV's production and replacement loads played a significant role, therefore technological investments to increase panels' durability and improve manufacturing efficiency could ensure its attractiveness.