Solar Canals

By Casey Bage, Law and Policy Clerk

 Photograph by Triddle, 2005

Solar canals address multiple problems at once. The impacts of climate change are so far-reaching and so grave that any multifaceted solution able to combat two or three problems at once cannot be overlooked if we want to live in a world of abundance. The realization of plentiful clean drinking water, clean air, and clean reliable electricity requires big ideas and a willingness of siloed entities to look outside their own specified expertise. Water agencies across the west have just such an opportunity. An article written by Staff Writer Sammy Roth of the Los Angeles Times recently highlighted the option of covering open-air water canals with photovoltaic solar panels. The article was inspired by a 2021 study released by the Sierra Nevada Research Institute at University of California Merced in collaboration with the Environmental Studies Department at UC Santa Cruz that solar installs over aqueduct canals have a 20-50% higher net present value than ground mounted solar farms.

We do not have the amount of water we need and our crisis will only worsen if we do nothing. California is once again experiencing extreme drought, along with the rest of the entire Western United States.  Lake Mead, providing water for over 24 million people, is at its lowest levels ever. Placing solar panels over open-air canals combats future clean water shortages in multiple ways according to the UC Merced study and I tend to agree with their assessments. 

The first conclusion of the study is that covering open-air canals with a roof of solar panels reduces evaporation, saving massive amounts of water as it makes its journey to thirsty rural and urban communities alike. The projects could also reduce aquatic weed growth in canals and, most importantly, add additional renewable energy projects to aid us in the ultimate goal of combating climate change and reining in mega-droughts. That’s three separate benefits for increasing abundant clean water.

On top of water savings, the placement of solar over water creates multifaceted victories for solar energy as well. Solar panels work more efficiently in a cooler environment, like a water-cooled canal, leading to more kilowatts of electricity generated from each panel. On top of that, many states are finding push-back against solar farm development, including the desire to preserve natural spaces and arable farmland producing our food.  Placing panels on already developed land assuages those concerns as well. Interestingly, the study finds that solar installed over canals could have a 20% - 50% greater net present value than standard ground mounted solar farms, due to the multi-pronged list of water and energy benefits, including the opportunity for California farmers to utilize that solar power instead of polluting diesel generators to pump water to their farms.

Now for the rub. Development costs money. Complex stuff, right? California’s Department of Water Resources gets their electricity from hydro-electric dams at very cheap prices. But, since water levels continue to shrink, the dams will most likely have less water to churn out that cheap power. On top of that, the Department of Water Resources has a new goal of reducing its greenhouse gas emissions to 75% below 1990 levels by 2030 and 100% by 2040. Solar-panel-covered canals are a major opportunity for the department, considering it is the State’s single largest electricity user. Water experts in the agency have expressed challenges that need to be addressed in order for this concept to take flight, namely: the need for new transmission lines from the aqueducts, accessing the canals to conduct maintenance, and paying for the investment. While some might view this list of difficulties as a reason to kill this idea, I view it as the project already getting off the ground especially with Roth reporting that  department head Karla Nemeth is “‘all ears” and ‘glad this is getting another look.’” The marketing firm that inspired the UC Merced study is named Citizen Group and has now started the company called Solar AquaGrid LLC. They are interested in developing pilot projects with “smaller water agencies that operate their own canals.” 

Having been born and raised in California and made my adult home in Oregon, I would be remiss if I didn’t mention this as a great opportunity for Oregonians as well. Central Oregon could be a ripe testing ground for this concept. The Central Oregon Irrigation District alone has 700 miles of canals, much of which is open air including the two major canals (Central Oregon Canal and Pilot Butte Canal). Oregonians, including Deschutes County commissioners, are acknowledging that water conservation efforts are critically needed as extreme drought take hold.

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