California’s Project Nexus represents only the second solar covered canal in the United States, generating 1.6 megawatts of clean electricity over irrigation waterways.
California just turned irrigation canals into solar power generators with its new solar covered canal project. Project Nexus, a $20 million pilot program in the Central Valley, completed construction last month with 1.6 megawatts of panels installed above water channels that serve the region’s farms.
This matters because it’s only the second solar covered canal operating in the United States right now. The first one started producing power in October 2024 for the Gila River Indian Community near Phoenix, Arizona. These projects demonstrate that we can generate clean electricity without occupying valuable farmland or undeveloped space.
The California installation happened in two phases. Workers completed a 20-foot-wide stretch in March, then finished a roughly 110-foot-wide portion at the end of August. The Turlock Irrigation District’s canals now generate electricity while still delivering water to farms growing cotton, tomatoes, almonds, and hundreds of other crops.
Researchers will study how Project Nexus performs over time. Meanwhile, California universities and Solar Aquagrid are pushing to speed up deployment of more solar covered canal systems across the state.
The benefits of putting solar panels over water go beyond saving space. Early research indicates that water underneath helps keep panels cool, thereby improving their efficiency and electricity output. The shade from panels also prevents water from evaporating in drought-prone regions, such as California and Arizona.
The shade can also limit algae growth in waterways, reducing maintenance costs and keeping the water cleaner. In areas where every drop counts, that’s significant for water conservation efforts.
Solar covered canal projects might offer a faster path to clean energy than traditional solar farms. Big renewable energy projects are increasingly facing opposition in rural communities, where people don’t want their landscapes altered. Placing panels over existing infrastructure avoids that problem entirely.
These smaller installations can connect to nearby distribution lines, eliminating the need for the higher-voltage transmission infrastructure required by large solar farms. That cumbersome connection process often delays or kills big renewable projects.
See also: California’s New Climate Action Plan
David DeJong directs the Pima-Maricopa Irrigation Project, which is developing a water-delivery system for the Gila River Indian Community. He pointed out the cultural advantages. Why disturb land that has sacred value when you can put solar panels over a canal and generate more efficient power?
Currently, these early arrays primarily power on-site canal equipment, such as pumps and gates. But the potential goes much further. A coalition of U.S. environmental groups calculated that covering 8,000 miles of federally owned canals with panels could generate over 25 gigawatts of renewable energy. That’s enough to power nearly 20 million homes.
The same analysis found that a solar covered canal system on that scale could reduce water evaporation by tens of billions of gallons. In the western United States, where water scarcity is constant, those savings could make a real difference.
The technology isn’t perfect though. Elevating solar panels over canals is more expensive and involves greater technical complexity than conventional ground-mounted arrays. The structures require more concrete and steel. Wider canals may need support structures within the waterway itself, which can disrupt water flow.
However, developers believe they can find customers among irrigation districts struggling with high electricity costs. Ben Lepley founded Tectonicus, the engineering firm that designed the Gila River Indian Community’s 1.3-megawatt system. Lepley acknowledged that initial costs are higher but said projects move fast. By the following year, irrigation districts can have cheap electricity that provides stability over the 30-year project life.
The Gila River Indian Community built its first solar covered canal over the Casa Blanca Canal with a nearly $5.7 million grant from the Inflation Reduction Act. Irrigation districts in California, Oregon, and Utah received remaining funds for their own installations.
Construction is 90 percent complete on the tribal community’s second project, a nearly 0.9-megawatt array built with the U.S. Army Corps of Engineers. The community is self-funding a similar-sized project over the Santan Canal and developing a floating solar array on one of its reservoirs. Both systems are set to operate by early 2026.
All together, these installations will provide 4 megawatts of local clean energy generation. Lepley said his firm has become familiar with the economics of building these projects. They’ve developed a playbook for continuing solar covered canal development even without grant funding from the federal government.
The success of these early projects will determine whether solar covered canal technology becomes a standard solution for irrigation districts across the country. If the data from Project Nexus and the Arizona installations demonstrates cost savings and operational reliability, more districts may be willing to invest despite higher upfront costs.
