Study by UC Merced and UC Santa Cruz Researchers Finds Solar Panels Over Canals Can Save Money, Energy and Water

Covering California’s canals with solar panels could save 63 billion gallons of water annually, which is comparable to the amount needed to irrigate 50,000 acres of farmland.

March 19, 2021 – Covering 4,000 miles of California’s water channels could save billions of gallons of water annually and generate renewable energy for the state, according to a new study.

The study, carried out by researchers from UC Merced and UC Santa Cruz – including distinguished professor of engineering Roger Bales in collaboration with UC Water and UC Santa Cruz – was published in the journal Nature Sustainability.

The research examines the connectivity and cost of water movement across the state. It tested the thesis that by erecting a modular system of solar control panels over California’s exposed aqueducts, the state could reduce evaporative water loss and offer a number of advantages over traditional floor-mounted solar systems. The Solar AquaGrid study was carried out by NRG Energy with development support from the Citizen Group from the Bay Area.

The results show an annual saving of 63 billion gallons of water, comparable to the amount it takes to irrigate 50,000 acres of farmland or to meet the water needs of more than 2 million people living in residential areas. And the 13 gigawatts of solar energy the solar panels would generate each year would be roughly one-sixth of the state’s currently installed capacity – roughly half of the projected new capacity needed by 2030 to meet the state’s decarbonization goals.

“The SolarAqua Grid model offers a combined, integrated answer to solving our water / energy relationship.” Ballen said. “It can help address California’s underlying vulnerabilities while meeting state and federal commitments to generate renewable energy, reduce greenhouse gas emissions, and mitigate climate change. Solutions like these are not only feasible but are desperately needed than ever, especially as the region returns to what many researchers call a paleo drought – a worst-case scenario for water managers. “

“We were surprised by the significant savings in evaporation, which we estimate at 82%.” added UC Santa Cruz postdoctoral fellow Brandi McKuin, lead author of the report. “This amount of water can make a significant difference in regions with water scarcity.”

Since the solar panels protect the ducts from direct sunlight, they would not only mitigate evaporation, but also decrease aquatic weed growth and lower maintenance costs, while the evaporation that occurs actually cools the modules and increases their efficiency in converting sunlight into electricity.

The analysis shows that by adding solar covers over ducts that run over “already disturbed land”, developers can avoid lengthy environmental permits and right of way issues so systems can be deployed faster and at lower cost.

The study estimates that for California, the resulting annual savings in maintenance costs could be as much as $ 40,000 per mile of sewer. Additionally, shutting down old diesel pumps and generators in favor of solar systems would help cleaner air in California’s Central Valley, which suffers from the worst air quality in the country.

“What is most compelling about this study is that you add up the multiple benefits.” Ballen said“Solar over channels is the kind of rethinking California and the world need as we transform our economy and infrastructure towards a fossil-free, sustainable future.”

The UC Solar AquaGrid study is taking place at a time when the switch from fossil fuels to renewable energies is becoming more and more urgent. UC engineers are rethinking how aging water and energy infrastructures can adapt to the challenges of sustainable water management, catastrophic forest fires, multi-day power outages, and the “megadrought” of the American West – a prolonged stretch of extended arid conditions worse than anything seen since 1603 . according to a recent report in Science magazine.

The Biden government has called for rapid modernization of water, transportation and energy infrastructure to withstand the effects of the extreme climate. Federal agencies have been directed to identify new opportunities to drive innovation, commercialization, and the deployment of clean energy technologies and infrastructures.

California is calling for 50% of its electricity to come from renewable sources by 2030 and for all new passenger cars to be zero-emission by 2035.

This study shows a way to advance the mission of sustainability by using existing structures.

“Aqueducts are the arteries of our economic and social development and have captured the public’s imagination for centuries.” said former Chair of the State Water Board, Felicia Marcus. “A significant part of our state’s electricity bill comes from moving, treating and heating water. So water efficiency is also energy efficiency. We must find all ways to use water more efficiently, including curbing evaporation losses, as we also scale clean energy to meet the demands of the challenging century of climate change. “
Source: UC Merced

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