A new California initiative testing solar panels over irrigation canals in the Central Valley has demonstrated impressive water savings and energy production, hinting at a promising future for sustainable water and power management.
- Shading canals with solar panels cuts evaporation and algae growth dramatically.
- The pilot generated 1.6 MW from solar canopies over two canals.
- Full-scale adoption could save 63 billion gallons of water annually.
What happened
Project Nexus, supported with $20 million in state funding, installed steel-framed solar panels above two irrigation canals south of Modesto, California. These panels provided shade that reduced water evaporation by as much as 70% and suppressed aquatic weed and algae growth by up to 85% over an irrigation season. Together, the two canal segments covered an area equivalent to about one and a half football fields and generated a combined power output of 1.6 megawatts.
This pilot, a joint effort between University of California Merced, Turlock Irrigation District, and Solar AquaGrid, assessed the dual benefits of energy generation and water conservation. While the study initially focused on power production, the substantial water savings and maintenance reduction surprised researchers and provided new value to the project’s economics.
Why it feels good
California operates some 4,000 miles of open irrigation canals, vital for delivering water to farms and communities. Modeling from a 2021 UC Merced study showed that installing solar panels along these canals could produce up to 13 gigawatts of renewable electricity—half of California’s 2030 solar goal—and save 63 billion gallons of water annually. This could support millions of residents or irrigate tens of thousands of acres of farmland.
Besides energy and water advantages, the 85% cut in aquatic weed and algae growth means less manual maintenance and fewer chemicals, benefiting local ecosystems and reducing operational costs. The project offers a hopeful glimpse at combining clean energy production with water resource stewardship, especially relevant amid ongoing drought pressures.
What to enjoy or watch next
Building on the pilot’s success, the Turlock Irrigation District is considering expanding solar canal installations pending a forthcoming UC Merced report, expected to provide critical insights for further investment. Meanwhile, California’s Department of Water Resources is evaluating similar projects on its statewide water network serving 27 million people.
International and regional examples, like Gujarat’s decade-old solar canals in India and Arizona’s recent projects, demonstrate this technology’s growing global appeal. Experts suggest that even covering a small fraction of California’s canal system—around 100 miles—could spark widespread adoption, unlocking up to one gigawatt of solar power and transforming water and energy management in the American West.