By Jeff Kronenfeld / NewsBreak Pinal County, AZ
(Pinal County, AZ) As Pinal County faces cutbacks to its water supply, up north drought threatens to turn Lake Mead into a dead pool — meaning water levels are too low for Hoover Dam to generate power.
Tectonicus with the Solar River project could help offset this potential loss by saving water while producing electricity.
The company estimates covering all of Arizona’s canals with solar panels could save 70,743 acre-feet of water every year, roughly enough to fill the Houston Astrodome 75 times.
However, if implemented over Arizona’s 13,164 acres of canal surface, the company estimates the project could produce 17.2 terawatt-hours of power annually.
For comparison, the Hoover Dam generates four terawatt-hours per year on average, according to the Bureau of Reclamation.
Through projects with the Gila River Indian Community and Biosphere 2, Tectonicus continues developing innovative solutions to the severe problems facing Arizona's energy-water nexus.
Solar River’s headwaters
When Ben Lepley first read about India’s Canal Solar Power Project in 2015, he recalled his days at the Southern California Institute of Architecture, where he earned his bachelor’s degree. Specifically, he remembered the long rides through the desert to visit Tucson, his hometown.
“I would always drive by the CAP canal, and just looking at it, baking under the sun and using lots of carbon-based electricity, I thought, this idea out of India would be just spectacular for our state,” Lepley said.
He explored the concept as head architect for Tectonicus and as an educator at the University of Arizona, leading a design studio on the subject.
At Tectonicus, his team created initial concept renderings for the Solar River project.
In 2019, the company won a small business innovations grant for a feasibility study. Soon after, they joined forces with George Cairo Engineering, a firm with lots of experience in large-scale canal projects, which shared an interest in powering canals with solar panels.
Power where it’s needed
Ensuring communities, farms, and businesses have enough water in the desert uses a lot of electricity.
For example, the state’s biggest energy consumer is the Central Arizona Project, which operates a canal system that rises more than 2,900 feet over its 336-mile-long course. It also provides water to Pinal, Pima, and Maricopa counties.
Even the CAP is just one of many public and private entities fighting gravity to keep the desert hydrated. Unfortunately, most of that electricity comes from thermoelectric power sources like coal, oil, gas, nuclear, and geothermal. All of these use steam to spin turbines, which expends a lot of water.
"The more solar and wind energy you create, the less demand you have on thermoelectric power plants, and therefore the less water you use in those power plants," Lepley explained. “With thermoelectric power, that water leaves into the atmosphere and does not come back ever, or maybe comes back in a rainstorm 10 years later. So, that's a big problem that's called consumptive use.”
Even worse, water exhausted from these plants is a potent greenhouse gas.
In contrast, photovoltaic solar panels directly convert sunlight into useable electricity without water. Further, placing solar arrays over canals reduces evaporation while increasing panel efficiency. Covering canals could also reduce algae growth, improve water quality, and avoid roadblocks encountered by other solar projects.
"In Pinal County, there have been a number of large utility-scale solar projects that have been cancelled in the last few years due to environmental impacts,” Lepley said. “When you're covering a canal, you're not bulldozing farmland. You're not bulldozing desert.”
Partnerships and paths forward
Tectonicus is one of the first four companies to participate in the U of A Center for Innovation at Biosphere 2, where construction of a test canal segment is underway.
“I want to thank them for the opportunity to build a prototype there,” Lepley said. “It's a really excellent incubator. They've been very supportive.”
Tectonicus and George Cairo Engineering also won a competitive bidding process to construct a solar panel array over a quarter-mile length of the I-10 Level Top Canal near Wild Horse Pass Casino.
The design ensures canal maintenance can proceed without expensive specialized equipment. Once complete, the project will be able to deliver 876 kilowatt-hours of power to the Gila River Indian Community.
“Our goal is for the I-10 Level Top Canal solar over canal project to be the first in a series of solar over canal projects that will ultimately lead to the complete carbon neutrality operations of the Gila River Indian Irrigation and Drainage District,” explained David DeJon, project director for the Pima-Maricopa Irrigation Project.
Lepley wants to do even more, including covering the CAP Canal, the All-American Canal, and many other canals across the Western U.S. If he succeeds, a gleaming solar river could pave the way to a brighter, more sustainable future for the Copper State and beyond.