Solar Canals Are Coming For Your Fossil Fuels

With thousands of miles of irrigation canals to its credit, the US is ripe with opportunities to establish itself as a leader in the solar canal movement, which is opening up new sites for solar development on existing water infrastructure. Take Texas, for example…then again, maybe not. Let’s start with California, where researchers hot on the trail of best cases for site selection among the state’s 4,000 miles of irrigation canals.

What’s Wrong With Solar Canals?

If your state hosts bucolic walking trails alongside canals, you can spot one problem right off the bat. Not every canal is suitable for solar development. After all, when you drive out to your local canal trail to reconnect with nature, a long stretch of solar canopy is the last thing you want to see — aside from coal mines, oil derricks, and gas wells, that is.

Generally speaking, though, the solar canal concept has a lot of appeal, similar to that of floating solar panels. Both can be placed on or over existing human-made water infrastructure, helping to prevent evaporation while generating clean kilowatts and avoiding some of the land use issues that can limit rural solar development.

The technology challenges are different for floating solar panels on reservoirs and installing solar canopies over canals, which explains why the former field is already in commercial production while the latter is still in the demonstration phase. Still, a good case can be made for hanging solar canopies over canals. “Solar canals have the potential to produce several benefits: reducing evaporation of vital water, conserving land by using existing infrastructure, and generating electricity more sustainably,” explains the Sol Price School of Public Policy at the University of Southern California.

“The projects could also provide economic benefits to the communities where solar canals are built,” USC adds.

Solar Canals: From A Trickle To A Flood

The solar canal idea crossed the CleanTechnica radar all the way back in 2012, when a solar-equipped canal project in India got under way.

More recently, in 2022 the Turlock Irrigation District in California announced a plan to test solar canopies over its irrigation canals, under a public-private partnership called Project Nexus. The plan included hanging a total of 8,500 feet of solar panels over three sections of a canal, as a proof-of-concept demonstration.

“Don’t get too excited just yet,” CleanTechnica advised at the time. “Plastering solar panels over canals is not as simple as it may seem. Anti-corrosion measures, additional installation expenses, and a specially trained workforce are among the complicating factors.”

Still, Project Nexus already has company. In  November of 2023 the Gila River Indian Community in Arizona dropped word on a solar canopy demonstration project for the Casa Blanca canal, supported by a $6 million grant from the US Department of the Interior.

In addition to other benefits, DOI cited the potential to reduce canal maintenance costs, as the shade from the solar panels is expected to inhibit algae and aquatic plant growth.

4,000 Miles Should Yield At Least A Few Solar Canals

Meanwhile, researchers in California apparently liked what they saw from Project Nexus. Building on the Turlock project is the new California Solar Canal Initiative, a research project aimed at culling through the state’s 4,000 miles of irrigation canals to guide stakeholders towards the most suitable sites, including state government agencies, utilities, policymakers, and developers among others, with the help of an online tool.

“CSCI is one of the most ambitious multi-benefit academic research projects in California’s history, with faculty experts from seven universities, including USC, participating,” the Price School explains, noting that partners include the research hub USC Dornsife Public Exchange and Solar AquaGrid, the company tapped to develop the Project Nexus solar canals.

Among the academic institutions to partner in CSCI is San José State University, which plans to focus attention on the justice aspect of solar canal projects. Part of the effort involves comparing solar canals to conventional utility-scale arrays on environmental justice issues as well as environmental impacts and community support.

“The CSCI research project aims to rapidly increase the use of solar power across the state by equipping government agencies, utilities, community members and other interested parties with data on optimal locations for panels and helping to identify willing host communities,” SJSU emphasizes.

Here Come More Solar Canals

The calculation of 4,000 miles of canals in California comes from a study published in 2023 by researchers from UC Merced and UC Santa Cruz. They concluded that covering all 4,000 miles with solar panels would save up to 63 billion gallons of water annually by reducing evaporation, in addition to providing new opportunities to generate solar power without impinging on land resources.

That’s just part of the solar canal potential in the US. Last year UC Merced described a project to be located on the Delta-Mendota Canal, as part of a three-state demonstration project funded through the 2022 Inflation Reduction Act. The other two states are Oregon and Utah.

The three-state program is of particular interest because two of the projects, in California and Utah, will explore the use of floating solar panels. The Utah project will deploy the canopy approach.

No word yet on whether or not the Trump administration will try to claw back the funding.

Meanwhile, Texas is another state that presents some interesting solar canal opportunities, although one opportunity that is probably off limits is the Gulf Intracoastal Waterway, stretching 1,300 miles from Saint Marks, Florida to Brownsville, Texas. The GIW is an active commercial transportation corridor, which most likely precludes dual use for solar power generation.

Aside from GIW, Texas does host a few hundred miles of canals for industry as well as irrigation and drinking water. However, the prospects for saving water and generating clean power from that infrastructure are dimming by the minute.

Legislators in Texas used to support renewable energy development hand over fist, enabling the state to handily beat all others for wind generation and creep up next to California for solar generation. However, today’s Republican lawmakers are horses of a different color. They have spent the past several years attempting to block renewable energy, and one of these days they might just succeed.

Image (cropped): Solar canals deploy existing infrastructure for clean power, with the added benefit of conserving water in addition to generating clean power (courtesy California Solar Canal Initiative via Price School).