Assessing upper bounds for solar-powered controlled environment agriculture on existing cropland

Controlled environment agriculture (CEA) has been proposed as a way of limiting cropland expansion and extending growing seasons, but these systems demand substantial amounts of energy, and their associated environmental impacts remain unclear. Here, we developed a framework to compare global crop area and production (reference year 2020) with an idealized, upper-bound scenario consisting of high-tech greenhouses or vertical farms powered by stand-alone photovoltaics (PV) for wheat, soybeans, potatoes, and tomatoes. The CEA energy calculation was combined with land-use, crop mapping, and PV energy datasets to compare CEA capacity with 2020 global crop production values. Of the 420 Mha of cropland area included in this study, hypothetical high-tech greenhouses and vertical farms powered by stand-alone PV arrays could match 2020 production levels on 313 Mha (74.5% aggregated across the four crops on the studied cropland area) and 275 Mha (65.4%), respectively, in the optimistic upper bound scenario. The modelled potential was greatest in parts of North and South America, South Asia, East Asia, West Africa, the Mediterranean, and Central Asia. ... mehrThese results reflect an idealized comparison, and implementing sustainable CEA at scale would face substantial technical, economic, and societal challenges. However, the framework does illustrate the locations where land and PV energy constraints would be least restrictive for CEA implementation.