Researchers from the University of California have looked at alternatives to installing solar on land that could otherwise be used for crops, and developed a model using California’s central valley as a case study.

The model evaluates four different alternative land types for PV deployments – urban rooftops, walls and building facades, land which is too salty for crops, contaminated land such as brownfield and superfund sites, and water reservoirs suitable for floating PV installations.

The researchers delineated a 58,815 km² region of California’s Central Valley to make their calculations, and using satellite radiation models developed at the National Renewable Energy Laboratory, theorized that these four land types have the potential to host PV installations generating at least 17,348 TWh/year – around 13 times California’s projected annual electricity demand up to 2025.

In regions where space for solar is limited, particularly in Japan and Taiwan, alternatives such as floating PV installations have already begun to make a splash, although Governments here are still likely to face some difficult decisions regarding the trade off between energy and food security.

While space is at somewhat less of a premium in California, it is still a vital agricultural region, and efficient land use is an important concern for the future.

The study, ‘Land Sparing Opportunities for Solar Energy Development in Agricultural Landscapes: A Case Study of the Great Central Valley, CA United States,’ is published in the American Chemical Society’s Environment Science and Technology Journal.