Environment

Project Nexus aims to cover California canals with solar panels

Project Nexus aims to cover Ca...
A rendering depicting how the photovoltaic panels will be situated over irrigation canals in California's Central Valley
A rendering depicting how the photovoltaic panels will be situated over irrigation canals in California's Central Valley
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A rendering depicting how the photovoltaic panels will be situated over irrigation canals in California's Central Valley
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A rendering depicting how the photovoltaic panels will be situated over irrigation canals in California's Central Valley
For the pilot project, 8,500 feet of panels will be installed
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For the pilot project, 8,500 feet of panels will be installed

While solar farms are a great source of green energy, many people don't like the fact that they occupy land which could otherwise be utilized for agriculture or housing. A new project is exploring an alternative, by placing solar panels over canals that will benefit from the shade.

Known as Project Nexus, the US effort is a collaboration between the University of California-Merced, California's Turlock Irrigation District, the California Department of Water Resources, and Solar Aquagrid – the latter San Francisco Bay-area company commissioned the research, and is overseeing the project.

The basic idea is that instead of placing arrays of photovoltaic panels on land that could be used for other purposes, those panels will instead be installed over lengths of existing irrigation canals. Not only is that space not really usable for much else, but the shading effect of the panels should significantly reduce evaporation and weed growth in the water.

As an added bonus, it is believed that the cooling effect of the water will help keep the panels from overheating, allowing them to operate more efficiently.

Plans call for a total of 8,500 feet (2,591 m) of solar panels to be built over three sections of the Turlock Irrigation District's canals in California's Central Vally, starting this Fall and ending in late 2024. The different canal sections range in width from 20 to 100 feet (6 to 30.5 m).

For the pilot project, 8,500 feet of panels will be installed
For the pilot project, 8,500 feet of panels will be installed

Based on research that was conducted last year at UC Merced, the project partners estimate that if 4,000 miles (6,437 km) of California's canals were covered with photovoltaic panels, evaporation could be reduced by up to 82 percent. This would save approximately 63 billion gallons (238 billion l) of water per year.

Additionally, if every canal in the state were covered with panels, approximately 13 gigawatts of renewable power could be generated – that figure is about half the amount needed to reach California's goal of full decarbonization by 2030.

"Solar canals are an example of an energy-water nexus that offers multiple sustainability benefits," says researcher Brandi McKuin, who will join the team at UC Merced next month. "Using water canals for solar infrastructure conserves water while producing renewable electricity, and avoids converting large tracts of land to solar development."

There may be some challenges to overcome, however. For one thing, the presence of the panels could make it difficult to access the canals for maintenance purposes. Additionally, it's possible that the expense of installing and maintaining the panels – along with delivering electricity from them to municipal grids – might outweigh the benefits they provide.

It is hoped that Project Nexus will be able to evaluate and address such concerns.

Sources: University of California, Project Nexus, Solar Aquagrid

15 comments
15 comments
Smokey_Bear
While I'm no fancy pants sciencegineer, this dun sounds like a good idear.
Eddy
A vast area of canals in the UK where this could be utilised.
Noah Tall
I was wondering what kind of provisions were made to keep the surfaces of the canal covers clean from sand deposited by storms, which I imagine might be a factor in maintaining these installations.
David F
If only the Martians had done the same, their canals might still have water. ;-)
CarolynFarstrider
The Israelis did the same thing with lakes and reservoirs about a decade ago. Interesting comments on whether the benefits outweigh the disadvantages. The study would need to look at to whom the benefits accrued. Climate change is worth mitigating, but the benefits are widely spread, whereas the costs of installing and maintenance relate only to the electricity company, and the additional costs of maintaining canals, to the water undertaking.
pmshah
We started doing this in India years ago. Does several things. Does not take up any additional land. Don't need 2 separate approach roads for maintenance crews. Drastically reduces evaporation losses. Prevents sand and other contaminants screwing up the canal floors. The solar panes have to be maintained and cleaned in either case. What they can try though is borrow the idea from Germany. German engineers studied the Lotus plant. They managed to produce glass panels with the same surface texture as Lotus leaves. These leaves never get dirty nor allow any dust to adhere. These glass panels are used outside high rise buildings. Now these building don't need services of any kind of "window washers". Wind or rain simply cleans it out.
rpark
...seems like a good idea, but panels should be angled enough to shed rainwater into the canal and secured adequately, so they don't blow away in the first wind storm.
Bob Flint
FPV Floatovoltaics;
https://news.energysage.com/floating-solar-what-you-need-to-know/

With some minor modifications periodic submersion to clean the surfaces would be possible...
PAV
Add a pump, water tower, and a generator, and you can store energy too!
Red
Build a track on each side of the canal. All modules of panels ride on trucks of track wheels. The support of all trucks can extend so if the canal gets wider, they can accommodate the width. Leave gaps every 500 feet so if maintenance is required, simply slide them apart. All modules should have a structure to allow a large eyelet at its middle so a maintenance road crane can lift it out of the way and back.

Previz, constructive dreaming. Add VFX artists to the engineering team. We dream, engineers build.
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