Evaluating agrivoltaics for microclimate regulation and food-energy co-production in cities and small-scale farming

Solar photovoltaics deployment, the largest share of renewable energy, is growing rapidly globally due to a decline in prices, aiming at decarbonizing the electricity sector. Yet, its promise of sustainability is majorly hindered by land competition with agriculture and grasslands due to similar site requirements and financial incentives for the unstable revenues of farmers. Such land conversion can imply ecological, environmental, socioeconomic, and technical damage, including destruction of vital fauna and flora habitats, loss of vegetation, yields, and carbon storage, soil erosion, an increase in ground heat fluxes, reduction in energy production efficiency, disarming generations of agricultural cultural values, and an unwelcome change in scenery. Thus, multi-land use strategies such as agrivoltaics, rangevoltaics, and ecovoltaics —integrating solar energy with crops, rangelands, and ecological restoration, respectively— are emerging as a solution to maximize land use efficiency and minimize harmful impacts. While land sharing can provide numerous interdisciplinary synergies, findings from previous research are all over the place, with minimal focus on the benefits of collocation on energy production and mitigating cities’ global issues (i.e., urban heat island, food and energy insecurity). Therefore, this work addresses these critical gaps by (1) conducting a global synthesis regarding the synergies and tradeoffs of collocated systems, (2) assessing the changes in microclimate and agricultural yields of a pilot agrivoltaics site throughout three growing seasons, and (3) spatial mapping and analyzing the extent of community urban agrivoltaics to secure food and energy to low-income neighborhood in cities. Findings show that improvements in food-energy production and other co-benefits are often site-specific, depending on background climate, soil conditions, and system design. In cities with a temperate climate, nonsignificant changes in air and soil temperature under the panels occur in most of the growing season, with the potential of an increase in cooling with the intensification of heat. In these systems, the combination of temperate temperatures and light reduction reduced the cumulative yields for some vegetables (i.e., cherry tomatoes, beans, lettuce, radish, basil; up to 40% compared to full-sun environment), while showing potential for yield compensation during hot periods and if grown in certain location of the agrivoltaics site (i.e., edges, center). On the contrary, leafy vegetables thrived under the panels by providing yields during times when full-sun environments were not suitable for plant growth and by protecting mature yields from plant desiccation during extreme heat events. To benefit from these systems, investing in community-based agrivoltaics in vacant lands in U.S. cities is technically more adequate than the abundant pitched rooftops to secure food and energy for low-income neighborhoods. These results (1) constitute a foundation for urban farmers to sustainably design community gardens and farms, (2) aid policymakers in prioritizing urban agrivoltaics as climate-and anthropogenic-adaptive infrastructure, (3) provide insights to stakeholders on the pathway to increase investments in cities by successfully running collocated systems and increase public acceptance, and (4) support urban planners in developing scalable, cost-effective solutions for urban sustainability.