California Eyeing Huge Water Savings As Evaporation is Slowed By Solar Panels Built Over Canals

With the world’s largest irrigation canal network, and years that can reach 290 days of sunshine, California is uniquely positioned to exploit this emerging innovation of canal-covering solar farms.

UC Santa Cruz is investigating this method as a possible generator of solar energy that would allow for the saving of 63.5 billion gallons of water from evaporation annually, a massive windfall for a state that sometimes rations water and which regularly suffers from droughts.

However the story begins in the Indian state of Gujarat in 2014, when a pilot project covering 750 meters of canal space led to the creation of an entire canal-top solar plant in Vadodara District, and another one totaling 100 megawatts off the Narmada River.

Researchers in India found that the water running underneath the panels cooled them down and prevented them from overheating, resulting in an average efficiency increase of between 2-5%.

Brandi McKuin and her colleagues at UCSC wanted to model the pros and cons of covering the Golden State’s 6,000+ kilometers of canals in solar panels, including using three separate techniques to measure water loss in different areas through evaporation, and which method of construction would be the most efficient at scale. Their results published in Nature Sustainability model a sunny future.

Covering an average of 30 meters, it was found that California’s canals when spanned with solar panels would save upwards of 63 billion gallons of water annually, and that the cost savings from water conservation, avoided land costs, aquatic weed maintenance, and enhanced electricity production outweighed the increased cost of building the more complex array. The most value conducive method of construction was with steel cables.

Furthermore, the state uses diesel-powered water pumps to drive the flow of the canals, which could be replaced to the tune of 15-20 generators per megawatt of solar. Lastly the reduction in land use means that California’s biodiverse arid lands could remain in the possession of native wildlife, or depending on the zip code, be bought for beef production or agriculture—adding jobs to local economies and increasing the food supply.

Leave a Reply

Your email address will not be published. Required fields are marked *