Arrayed relations and runoff regulations: Stormwater governance and the hydrosocial territorialization of Pennsylvania grid-scale solar development

Solar photovoltaics are crucial technologies for purposive low-carbon energy transition, yet there is uneven oversight of the development of grid-scale solar facilities around the US. Where other forms of regulation are absent, National Pollutant Discharge Elimination System (NPDES) construction site permitting programs may take a prominent role in governing solar development. In this paper, we use the lens of hydrosocial territorialization to reveal how socio-material relations and power dynamics configured through this Clean Water Act program shape Pennsylvania solar energy landscapes. We specifically ask: 1. How has water regulation come to regulate grid-scale solar development? 2. How does the NPDES governance process work when regulating grid-scale solar developments, specifically, and who and what influence the process? 3. How does solar development, regulated through the NPDES program, become a form of hydrosocial territorialization? 4. How does conceptualizing grid-scale solar development as a hydrosocial territorialization process inform geographic scholarship on energy transitions? Through a case study in Pennsylvania, where grid-scale solar development has rapidly increased in some agricultural regions, we reviewed regulatory documents, conducted key informant interviews with individuals involved in NPDES governance, and conducted a focus group of residents who live near grid-scale solar development. Through our analysis, we uncover nuances in these hydrosocial relations that are not included in regulatory documents. Through their authority, expertise, and discretion, engineers, contractors, and county and regional officials influence the hydrosocial territorialization process; at the same time, vegetation and soil materialities also shape solar facilities. As development progresses around the United States, the NPDES program will continue to spur generation or modification of relationships, knowledge, and regulatory interpretations, reconfiguring rural geographies and solar landscapes in the process.