Solar Panels Over Canals: California's Innovative Energy Solution

California launched the nation's first solar-over-canal pilot project in October 2022, breaking ground on a $20 million program known as Project Nexus in the Turlock Irrigation District (TID). The pilot places solar panel canopies over sections of open irrigation canals at two sites in Stanislaus County — a 500-foot span near Hickman, east of Modesto, and a mile-long stretch near the city of Ceres.

Project Nexus is a public-private-academic partnership among the Turlock Irrigation District, the California Department of Water Resources, UC Merced, and development firm Solar AquaGrid. The state is funding the pilot with $20 million from the California general fund, which was formally accepted by TID in February 2022.

The pilot covers both narrow- and wide-span canal sections — ranging from about 20 feet to 100 feet wide — so researchers can evaluate performance across different real-world conditions. Expected co-benefits include renewable electricity generation, reduced evaporation from the covered water surface, suppression of aquatic weed growth in the canal, and potentially improved solar panel efficiency due to the cooling effect of the water below.

The concept is grounded in a peer-reviewed UC Merced study, which estimated that covering California's roughly 4,000 miles of public water-delivery canals with solar panels could save about 63 billion gallons of water per year — enough to irrigate 50,000 acres of farmland or meet the residential water needs of more than 2 million people — while generating an estimated 13 gigawatts of solar capacity, a substantial share of the new solar the state needs to meet its decarbonization goals by 2030.

For California homeowners and ratepayers, Project Nexus is a proof-of-concept rather than a direct rebate or incentive program. But if the pilot succeeds, dual-use solar-over-canal infrastructure could lower system costs, reduce pressure on farmland for utility-scale solar siting, and help stabilize long-term water and electricity supplies statewide. Construction on the first panels progressed through 2024 and 2025, with TID reporting the canal solar installations complete and commissioned by 2025.