Ultra-high photovoltaic penetration: Where to deploy

While it is widely known that the solar resource is sufficient to meet the world's energy demand many times over, the questions of where and how much to deploy in a realistic context do not have such clear-cut answers. The objective of this paper is to address and inform these questions in a context where solar (embodied by PV) would be applied locally to firmly meet the bulk of energy demand from regional economies. Sensible answers are important in light of growing societal mandates to displace carbon-based energy resources. We aim to provide realistic and comprehensive numbers that can effectively inform planning decisions at local and regional levels. We focus on the continental United States (CONUS) and develop state-specific PV deployment requirements informed by: A full accounting of states' energy requirements from the electric sector as well as [to be] electrified transportation and building (HVAC) sectors. Positing that the bulk of this demand will be met within each state with an optimized blend of PV and wind with a small residual allowance for dispatchable generation - an optimized blend of resources estimated from our recent grid-specific investigations in diverse climatic and socioeconomic environments. A recognition that electrical demand must be met firmly, hence that intermittent renewables must be transformed into firm, effectively dispatchable resources available 24/365 to maintain a stable electrical grid. A recognition that the least-cost solution to achieve this intermittent-to-firm transformation implies overbuilding and proactively curtailing these resources we apply herein an estimated overbuild amount estimated from our recent investigations in diverse environments. Not accounting for likely energy efficiency improvements in any of the three considered demand sectors. Therefore, the numbers developed can be considered to be conservatively high. From these requirements, we explore PV deployment options using two distinct approaches: a top down approach assigning a fraction of plausible deployment potential to land use classes as defined by the US geological Survey, and a bottom-up approach starting from end-use applications prospectively amenable to PV deployment without change of function. In addition, we provide readers with an online interactive capability to modify fractional land use selections applied in this article and further investigate state-specific potentials. We conclude that a majority of the three-sector firm power requirements could be met economically and firmly by locally-deployed PV resources with ample deployment room to grow, even in the most densely populated northeastern states. This conclusion applies even before considering energy efficiency improvements or tapping other renewable resources that may be available locally (e.g., hydropower).

Automated summary

This paper aims to address the practical questions of solar energy deployment to meet regional energy demands. With comprehensive data and methods, it concludes that there is ample solar resources available for deployment, even in densely populated areas, to economically and reliably meet power requirements.