What solar panels over irrigation canals in California actually do
Solar panels built over irrigation canals in California finished construction in 2025, and the idea behind them is simple. A panel mounted above a canal shades the water below, so less of it evaporates into the air, and the water below cools the panel, so the panel makes more electricity in the heat than one sitting on dry land. Turlock Irrigation District, the public utility that owns the canals, built the first real test of that idea at 2 sites in the Central Valley, spanning a canal section 20 feet wide and a second section 110 feet wide, together generating over 1.6 megawatts of power, enough to test the idea at a real scale, not only in a study.
Turlock Irrigation District canals generally range from 20 to 100 feet wide across the whole system.
Show the numbers
| Narrow span section, built for Project Nexus | 20 |
| Widest typical canal in the system | 100 |
| Wide span section, built for Project Nexus | 110 |
Finished in August, announced 8 months later
Turlock Irrigation District states, on its own project page, that the narrow span was fully mounted by March 2025 and the wide span was completed and commissioned by August 2025. The office of Governor Gavin Newsom did not issue a press release calling the project complete until April 29, 2026, 8 months after the utility itself says construction actually finished. The 20 million dollar pilot was funded by the governor and the legislature, and runs as a partnership between the California Department of Water Resources, Turlock Irrigation District, the company SolarAquaGrid, and the University of California, Merced.
So putting solar arrays near this facility that saves water, combined with the new renewable energy source, goes to the core of TID's innovative spirit!
Bill Penney, civil engineering department manager, Turlock Irrigation District. Source 5.
Built smaller than first planned
The trade publication Civil Engineering Source, run by the American Society of Civil Engineers, reports the finished project covers about 1,700 linear feet of canal, down from an original plan of about 8,000 feet, a scope reduction no other source confirms. That same account is the only one that gives a count for the batteries installed at the narrow span site, 2 separate 75 kilowatt iron flow batteries, a battery design that stores energy in tanks of liquid instead of a solid cell. Turlock Irrigation District describes the batteries on its own project page but does not say how many are installed.
This scope reduction is stated only by Civil Engineering Source. The project page kept by Turlock Irrigation District does not give a planned figure to compare against.
Show the numbers
| Covered by panels | 1700 |
| Originally planned | 8000 |
The 63 billion gallon number is a model, not a result
Turlock Irrigation District repeats, on its own project page, the projection from a 2021 peer reviewed study, that covering every canal in California with solar could save 63 billion gallons of water a year, enough to irrigate 50,000 acres of farmland or meet the residential water needs of more than 2 million people, and could add 13 gigawatts of power, more than half the new solar capacity the state projects it will need by 2030. But that is a statewide model built from covering the whole canal network, not a measurement of the 2 real sections Project Nexus actually built. The same utility that built those 2 sections says, on that same page, that real water conservation data from them is not yet known and will be worked out later by the University of California, Merced. The 2021 study behind the model also found that a cable supported design for spanning a canal returned 20 to 50% more financial value than the alternative design it tested.
A similar project in Arizona, and a caution from the engineer who built this one
Project Nexus is only the second solar array built over a canal in the United States. The first began running in October 2024 for the Gila River Indian Community near Phoenix, Arizona, at 1.3 megawatts.
Why disturb land that has sacred value when we could just put the solar panels over a canal and generate more efficient power?
David DeJong, director, Pima Maricopa Irrigation Project, speaking about the earlier Arizona canal solar project, not Project Nexus. Source 4.
Bill Penney says Turlock Irrigation District is already seeing reduced evaporation and less vegetation growing over the covered water, but calls firm conclusions premature this early.