California Switches On Canal-Top Solar With Storage
Published · 4 min read
Project Nexus is now online in California’s Central Valley. It puts solar panels over irrigation canals and adds a battery. The goal is simple: make clean power and save water.
What Is Project Nexus?
The Turlock Irrigation District (TID) built a 1.6-megawatt (MW) canal-top solar pilot. The state funded it with $20 million. The pilot sits in Stanislaus County, where farms grow cotton, tomatoes, and almonds. It uses two solar canopies. One spans a ~6-meter (≈20-foot) canal. The other crosses a ~30-meter (≈100–110-foot) canal.
The narrow section came online in March 2025. The wider section finished at the end of August 2025. Together, they now send power into TID’s grid and support canal gear like pumps and gates.
Project Snapshot
| Item | Details |
| Total capacity | 1.6 MW solar across two canal spans |
| Funding | $20 million (state-funded pilot) |
| Sites | ~6 m wide canal and ~30 m wide canal |
| Go-live | 20-ft span in March 2025; wider span in late August 2025 |
| Host | Turlock Irrigation District (TID), California |
| Aim | Test power output, water savings, and operations over canals |
Battery Storage: What It Adds
At the narrow canal site, TID installed a 75 kW iron-flow battery from U.S. maker ESS. Each container delivers about 400 kWh. The design is built for more than 20,000 cycles. It weighs about 41.9 tons and measures 12 m × 2.4 m × 2.9 m. The water-based electrolyte is fully recyclable and uses recycled iron and salt water.
| Battery Spec | Value |
| Power | 75 kW (iron-flow) |
| Energy per container | ~400 kWh |
| Cycle life | >20,000 cycles |
| Dimensions | 12 m × 2.4 m × 2.9 m |
| Weight | ~41.9 tons |
| Electrolyte | Salt water and recycled iron; fully recyclable |
Why Put Solar Over Canals?
Land is scarce. Farms need space. Wildlife needs space, too. So this design uses existing waterways and avoids new land use. It also taps nearby distribution lines, which can speed interconnection.
- Less evaporation: Shade can cut water losses in hot months.
- Cooler panels: Water below can lower panel temperatures and boost output.
- Cleaner water: Shade can reduce algae and plant growth.
- Fewer land conflicts: Arrays avoid fields and habitats.
- Local use: Power can run canal pumps and gates on site.
What the Research Will Measure
The University of California, Merced, set up instruments at both sites. The team will gather baseline data and track performance. They will study energy output, temperature, and water effects. Actual evaporation savings for this pilot are not known yet. But earlier research offers clues.
A prior University of California study estimated that covering about 4,000 km of canals in the state could save roughly 63 billion gallons of water each year. That could irrigate about 50,000 acres of farmland or supply more than 2 million residents.
How This Fits in the U.S.
Project Nexus is the second canal-top solar array to operate in the United States. The first began in October 2024 for the Gila River Indian Community near Phoenix, Arizona. Two more canal-top arrays are planned there. These early systems focus on local canal needs. But the idea could grow.
A coalition of U.S. environmental groups estimated that covering about 8,000 miles of federally owned canals and aqueducts could add over 25 GW of renewable power. That could serve nearly 20 million homes and cut water losses by tens of billions of gallons.
Costs and Trade-Offs
Canal-top solar can cost more than ground-mounted systems today. Spanning canals needs custom supports and careful work. But it may avoid land fights that slow big projects. It also uses rights-of-way that already exist. And it can connect to local lines. So, the total path to power can still be smooth.
What Comes Next
With both spans live, the pilot will collect real-world data through the seasons. California universities and Solar Aquagrid are also pushing to speed solar-canal deployment. They aim to find the best sites, standardize designs, and lower costs as projects scale.
Key Takeaways
- 1.6 MW of solar now runs over TID canals in California.
- A 75 kW iron-flow battery supports reliable output on site.
- The pilot cost $20 million and finished by late August 2025.
- Researchers will test power gains, water savings, and water quality.
- Covering 4,000 km of canals could save ~63 billion gallons a year.
- U.S. potential on federal canals is >25 GW and nearly 20 million homes served.
The bottom line: Project Nexus is small, but it is smart. It makes clean power and could save water. If the data holds up, more canal-top arrays may follow across the West — helping farms, communities, and the grid.
