The 1.6 MW Nexus pilot project in California has shown that solar panels installed over irrigation canals can significantly reduce water evaporation and algae growth by 85%, while also demonstrating operational efficiencies.
In September 2025, the Nexus pilot project was completed in California, United States. The 1.6 MW solar facility is located on canals managed by the Turlock Irrigation District (TID) and was developed through a public-private partnership between the California Department of Water Resources, TID, Solar AquaGrid and the University of California (UC), Merced. The project aimed to generate empirical data under real operating conditions.
The pilot, launched in 2022, evaluated the technical and operational feasibility of deploying PV systems on active irrigation canals. The concept enables dual use of existing infrastructure: clean electricity generation alongside reduced water evaporation and minimized land use – an approach that is especially relevant in agricultural areas such as California’s Central Valley.
The project monitors key performance indicators including electricity generation, evaporation losses, water quality, aquatic plant growth and canal maintenance requirements. After one irrigation season, the first results indicate measurable benefits for the water sector. Channel sections covered with PV modules showed reduced evaporation and lower aquatic weed proliferation, which can translate into lower operating costs.
Specifically, continuous measurements over an entire irrigation season have recorded a 50-70% evaporation reduction under the solar panels and an 85% reduction in algae growth, a result that could deliver operational efficiencies in canal management. These findings are consistent with previous research from UC Merced, which highlighted the potential of canal-based solar systems to improve water use efficiency in open canal infrastructure.
From an engineering perspective, the project also serves as a testing ground for multiple design configurations. These include long-span structures over wide channels, smaller systems on narrower channels, vertical installations along canal banks, and early-stage retractable prototypes. As previously reported by pv magazinea battery energy storage system (BESS) was also deployed at the narrowest location, using 75 kW iron flow batteries supplied by the American manufacturer ESS.
This series of configurations is intended to assess the adaptability of the system under varying hydraulic and structural conditions.
Project developers note that the scalability potential is significant given California’s extensive canal network. A UC study estimates that covering about 2,500 miles (4,000 km) of canals could save 63 billion gallons of water annually, the equivalent of irrigating 50,000 acres (20,234 hectares) of farmland or meeting the water needs of more than 2 million people. In addition to water savings, improved water quality through reduced vegetative growth is also important for TID.
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