In brief: California is set to become the first state in the nation to install solar panel canopies over canals in an effort to combat drought conditions. The pilot, dubbed Project Nexus, will involve the installation of an estimated 8,500 feet of solar panels over three sections of canals in the Turlock Irrigation District (TID). The sections vary in orientation and width, ranging from 20 feet across at the narrowest parts to around 100 feet at the widest.

The proof of concept is intended to increase renewable power generation and reduce water evaporation in canals. TID, in partnership with the state of California, the University of California Merced and development firm Solar AquaGrid, also expects to experience water quality improvements and lower maintenance costs through reduced vegetative growth in the covered canals.

The state also said putting panels over water instead of land can help keep them cooler by making them more efficient. It could additionally save permitting time and free up land for other uses.

TID cited a 2021 study from UC Merced (the aforementioned Project Nexus partner) that suggested covering 4,000 miles of public water delivery system infrastructure in California with solar panels could save up to 63 billion gallons of water annually. According to the study, that is enough to meet the residential water needs of more than two million people or irrigate 50,000 acres of farmland.

The estimated 13 gigawatts of solar power the theoretical panels would generate each year would equal about one sixth of the state's current solar capacity, the study further noted.

TID in its FAQ for Project Nexus said the amount of evaporation savings expected is currently unknown.

Project Nexus is being funded by the state of California at a cost of $20 million. That is rather expensive for 8,500 feet of solar panels that will cover 1.6 miles of the estimated 4,000 miles of public waterways in the state.

Construction is expected to get started this fall and wrap up by the end of 2023.