- Covering 4,000 kilometers of canals would save 63 billion gallons of water and generate 13 GW of energy per year.
- Pilot project shows significant drops in water loss and algae growth
- Critics argue that the project is too expensive and preventing canal evaporation may be counterproductive.
California’s extensive network of canals could become a massive source of clean energy while saving billions of gallons of water each year.
A University of California study found that covering approximately 4,000 kilometers of canals with solar panels would generate 13 GW of energy annually and save 63 billion gallons of water.
That amount of water is enough to meet the residential needs of more than two million people each year.
What the pilot project has shown so far
A small-scale demonstration called the Nexus project was built to test whether this concept actually works in real-world conditions.
The 1.6-megawatt Nexus installation is located on canals operated by the Turlock Irrigation District, and after a full irrigation season, covered sections of the canal showed evaporation reductions of 50 to 70% beneath the solar panels.
Algae growth was reduced by 85%, significantly reducing the cost of maintaining canals and cleaning water pumps.
Shading also keeps solar panels cooler than ground-mounted alternatives, improving their electricity production by approximately 2.5 to 5%.
India has already built similar canal-top solar projects, proving that the concept works in different climates and geographies.
Despite the clear benefits, this idea faces resistance and the main obstacle is cost.
Top-of-channel solar requires heavy steel support structures that must span the width of the waterway below, and these structures alone can account for up to 40% of the total project cost, significantly more than ground-mounted solar farms.
Critics argue that the canals are designed for water supply, not as foundations for industrial infrastructure.
Such designs would require regular access to the canals by maintenance crews for sediment removal and repairs, and raised panels would significantly complicate that work.
Some also point out that California has many cheap desert lands where traditional solar panels can be installed at a much lower cost.
Although a solar farm on desert land costs less and avoids engineering complications, it does nothing to save water, a long-standing problem in California, as the state has already lost 40% of its allocation from the Colorado River this year, and every drop saved matters.
What would need to be changed for widespread deployment?
The economic calculus of this idea changes when water savings are given a real monetary value.
Top-of-the-trough solar prevents evaporation in a state that regularly faces severe drought conditions and also generates electricity exactly where agricultural demand exists, reducing transmission losses from distant solar farms in the desert.
From another point of view, canal-top solar could alleviate data center power demand, which typically puts enormous pressure on local grids and water supplies.
It generates clean power exactly where it is needed, reducing transmission losses and avoiding the need for new transmission lines.
Water saved through reduced evaporation could be used to cool data centers instead of being lost to the atmosphere.
A single data center can use millions of gallons of water each year, and canal shade preserves that resource for productive use.
The 13 GW of potential generation from California’s canals could power hundreds of data centers without requiring additional land or straining the state’s overloaded grid.
That said, preventing evaporation, as canal-top solar will do, is not a guaranteed victory.
It will likely have minimal impact on local humidity and may disrupt aquatic ecosystems by reducing dissolved oxygen, which is like solving one problem while creating another.
The Nexus pilot will continue to collect data to determine whether California expands the concept or decides that the ecological and operational trade-offs do not justify the energy gains.
Via PV Magazine
Follow TechRadar on Google News and add us as a preferred source to receive news, reviews and opinions from our experts in your feeds.
