Photovoltaics in the built environment: A critical review

In this manuscript we review research on the feedback mechanisms between photovoltaic energy pro-duction and the urban environment, with an emphasis on synthesizing what is known, while drawing attention to limitations, and indeed errors in, the literature on this topic. We include in our analysis studies on photovoltaic (PV) systems in urban settings - on buildings, as shade structures, or as stand-alone arrays within an urban environment. We further limit the review to studies that investigate how the urban setting affects the performance of PV systems or how PV sys-tems affect their surrounding urban environment. Our review is based on a systematic search of the lit-erature, which revealed 116 unique articles that addressed the underlying questions in a meaningful way. While there are conflicting results reported across this body of literature, our review and synthesis reveal two key findings: (1) PV can significantly warm the city during the day, provide some cooling at night, and potentially increase energy use for air conditioning of buildings in some climates and building types; and (2) placing PV in an urban setting can adversely affect PV efficiency, reducing overall power produc-tion up to 20% in comparison to PV applications in rural settings. It is recommended that future develop-ments of PV technologies focus both on increased efficiency and the need to increase reflection of wavelengths of energy not converted to electricity by the PV cells. Furthermore, designs for urban PV sys-tems should explicitly consider the effects of elevated urban temperatures, pollution, and shading on sys-tem performance. (c) 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http:// creativecommons.org/licenses/by/4.0/).