A model for California? [image credit: Hitesh vip @ Wikipedia]
Worth asking what is meant by ‘could be economically feasible’ in this context. Running power stations 24/7 looks a lot simpler than having thousands of miles of solar panels to install and maintain, which sit idle without sunlight.
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UC Santa Cruz researchers published a new study—in collaboration with UC Water and the Sierra Nevada Research Institute at UC Merced—that suggests covering California’s 6,350 km network of public water delivery canals with solar panels could be an economically feasible means of advancing both renewable energy and water conservation.
The concept of “solar canals” has been gaining momentum around the world as climate change increases the risk of drought in many regions, claims TechXplore.
Solar panels can shade canals to help prevent water loss through evaporation, and some types of solar panels also work better over canals, because the cooler environment keeps them from overheating.
Pilot projects in India have demonstrated the technical feasibility of several designs, but none have yet been deployed at scale.
California’s canal network is the world’s largest water conveyance system, and the state faces both a drought-prone future [Talkshop comment: evidence-free assertion] and a rapid timeline for transitioning to renewable energy.
Solar canals could target both challenges, but making the case for their implementation in California requires first quantifying the potential benefits. So that’s exactly what researchers set out to do in their paper published by Nature Sustainability.
“While it makes sense to cover canals with solar panels because renewable energy and water conservation is a win-win, the devil is in the details,” said Brandi McKuin, lead author of the new study and a UC Santa Cruz postdoctoral researcher in environmental studies. “A critical question was whether the infrastructure to span the canals would be cost-prohibitive.”
Canal-spanning solar panels are often supported either by steel trusses or suspension cables, both of which are more expensive to build than traditional support structures for ground-mounted solar panels.
But McKuin led a techno-economic analysis that showed how the benefits of solar canals combine to outweigh the added costs for cable-supported installations. In fact, cable-supported solar canals showed a 20-50 percent higher net present value, indicating greater financial return on investment.
In addition to benefits like increased solar panel performance and evaporation savings, shade from solar panels could help control the growth of aquatic weeds, which are a costly canal maintenance issue. Placing solar panels over existing canal sites could also avoid costs associated with land use.
Now that the new paper has provided a more concrete assessment of these benefits, members of the research team hope this could lead to future field experiments with solar canals in California.
Full article here.
Tallbloke's Talkshop 
‘The concept of “solar canals” has been gaining momentum around the world’
[citation needed]
‘Canal-spanning solar panels are often supported either by steel trusses or suspension cables’
Often? Wut?
‘Ultimately, it was the cost savings of many combined benefits that made solar canals financially viable, rather than benefits from reduced evaporation alone.’
So, there you go. It IS financially viable.
‘But the study also notes that benefits from deploying solar canals could extend beyond immediate financial impacts. For example, every megawatt of solar energy produced by solar canals in California’s Central Valley has the potential to replace 15-20 diesel-powered irrigation pumps, helping to reduce pollution in a region with some of the nation’s worst air quality.’
Pumps being needed only between 11 AM and 3 PM. And the wiring to get the electricity out to these remote locations is FREE!
Wait! They could build megawatt batteries at the pumping stations!
Come to think of it, what else are you going to do with the electricity? How are you going to collect and distribute the electricity from a 6,350 km generator? Much of the aqueduct system is remote.
‘Zumkehr led a complex hydrological analysis using data from satellites, climate models, and automated weather stations to model and compare evaporation rates at canal sites across the state, with and without shade from solar panels. McKuin then used this information in her assessment to calculate the financial benefits of reduced evaporation.’
Cirrusly?
This is one of those academic reports where EVERY paragraph is problematic.
Interesting concept, so let’s expand the idea twofold. What would you say, to covering the lakes and oceans, rivers and streams. Bad ideas. So much of the world is alive because of the oxygen from those areas, so much of the world is alive because of the reduction of oxygen, produced by sunlight.
So far, no one has proposed research to produce transparent solar cells, that allow some energy be used for natural processes. Keeping our food weeds alive.
Report: For example, every megawatt of solar energy produced by solar canals in California’s Central Valley has the potential to replace 15-20 diesel-powered irrigation pumps, helping to reduce pollution in a region with some of the nation’s worst air quality.
You wouldn’t want any of that air pollution landing on your shiny solar panels, degrading their performance and/or requiring frequent cleaning that greatly adds to running costs (6000+ kms. to clean?).
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Why Does California’s Central Valley Have Such Bad Air Pollution?
The farming communities of the Central Valley breathe some of the worst air in the nation
. . .
Surrounded on three sides by mountain ranges, the Central Valley acts as a pool for pollutants produced by the region’s roughly 3.5 million residents, its industry and its large agricultural community. These emissions get trapped in the valley by an inversion layer of warm air, explains Dimitry Stanich of the California Air Resources Board.
. . .
The problem is getting better, but it’s by no means solved. As agricultural burn-offs continue to decrease, the Valley can expect to see its air quality improve. But regardless of the value of those improvements, its geography and meteorology distinctly disadvantage it to suffer below average air quality. [bold added]
https://www.bloomberg.com/news/articles/2011-09-28/why-does-california-s-central-valley-have-such-bad-air-pollution
“the devil is in the details,” said Brandi McKuin”
Forget the panels for a moment. Does it make economic sense to cover the canals in ancillary operation and maintenance costs? Are the panels maintenance free/minimal? If not, combining the two will not be mutually beneficial, but compound those problems. From an engineering POV, few such disparate designs are ever mutually beneficial.
Neophyte.
First they tried solar roads which were proved useless now they want to try solar panels over water supply channels with the added costs of the support structures plus the additional costs of getting the small, intermittent supply of electricity to where it would be of use, we must also remember that water and electricity don’t mix very well.
Stating that California faces a drought prone future is rather stupid especially when it is self inflicted by the green lobby to supposedly keep Delta smelt alive rather than keep farms and people alive.
It also appears that a lot of this ‘research’ is based on computer models, climate and others and we all know just how useful unvalidated models are – not worth wasting the electricity used to produce them.
Conclusion is that the stupid leftist greens will take this pie in the sky scheme up and spend billions on it and then wonder why it doesn’t produce the utopia they are looking for.
“its geography and meteorology distinctly disadvantage it to suffer below average air quality”
Wait . . . it’s not 15-20 diesel-powered irrigation pumps?
Note that “below average air quality” in the United States isn’t necessarily all that bad.
History is calling . . . Juan Cabrillo noted smog from Indian fires when he first saw the Los Angeles Basin in 1542. He called Santa Monica Bay “Baya de los Fumos.” Air pollution problems from geography in California have been known for nearly 500 years.
California faces a “drought-prone future”? Of course it does — it faced a drought-prone past, and is in a drought-prone present. Geography and long-term climate patterns will keep California drought-prone for the foreseeable future — maybe centuries.
Solar panels must be regularly cleaned and in dusty drought-prone California, the rain won;t come and wash them off. People will have to wash them – and it takes very regular washing, I have them on my boat. If not washed, they quickly reduce in output. How many civil servant salaried employees (with those high-end public employee pension plans and guaranteed pay increases) will it take to keep miles and miles and miles of solar panels washed — and will all the wash water simply fall into the drinking water canals?
Will they have to remove whole sections of panels to keep the canals weed-free?
It’s clearly b…..dy nonsense and not worth discussing.
They’ve been trying to get diesel irrigation pumps replaced by electric ones for nearly two decades…
New Program to Encourage Electrically Powered Irrigation Pumps
DATE: November 9, 2004
SACRAMENTO– The California Air Resources Board (ARB)
The ARB estimates there are 5,700 diesel irrigation engines operating in the Central Valley. If these engines were replaced with electric motors, an estimated 11,600 tons of NOx and estimated 860 tons of PM would be eliminated each year.
https://ww2.arb.ca.gov/news/new-program-encourage-electrically-powered-irrigation-pumps
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Re droughts, there are probably good reasons why LA for example takes some of its water from behind the Hoover dam, via 266 miles of pipeline. Such as routinely inadequate rainfall in their part of CA perhaps? 😎
Massive aqueducts channeled millions of gallons of Colorado River water to California where it continues to this day to flow from Los Angeles faucets and irrigate vast stretches of fertile cropland.
With Hoover Dam, the federal government set out to demonstrate that the aridity of a region once called the Great American Desert need be no serious obstacle to its full settlement and development. [bold added]
https://www.history.com/this-day-in-history/hoover-dam-begins-transmitting-electricity-to-los-angeles
Reblogged this on Climate Collections.
The blocking of sunlight to the canal will destroy the primary algal production in those canals, in turn destroying their ecosystems. Blocking of wind could cut off wind driven circulation leading to regions of anoxic water. In short they will kill the canals for a few paltry kW of widely distributed electrical energy. A poor trade-off.
I can’t wait to experience the Schadenfreude when the first flood tops those canals and wipes out hundreds of miles of solar panels, the first washed-out panels blocking the water and crashing into the next set of panels, further blocking the water and crashing into the next set of panels, so on an so forth, culminating in SoCal being awash in solar panel soup… a cascade of liberal lunacy. LOL
“People will have to wash them – and it takes very regular washing”
And how do you prevent the washings (dirt & cleaning agents) from dripping into the canals directly underneath? Many of these canals supply drinking water to large population centres, and I don’t imagine the utility companies will want the risk of completely unnecessary pollution added to their supplies. If any panels are damaged, you can add heavy metal pollution to that risk…
There’s nothing to stop birds (for example) fouling the canals now, and they run through areas of heavily polluted air anyway. The water must have to go through treatment plants before going into drinking supplies.
What are they going to do with the waste from all the defunct old panels in the future….. ?
Suppose they can keep the wind turbine composite blades company in some big hole in the ground somewhere.
I’m from there…
Grew up in farm land California. This “idea” is nutty from the get go.
First off, canals come in 4 major kinds.
1) Giant Water Program to L.A.
2) Drainage ditches
3) Major distribution for irrigation.
4) Minor distribution for irrigation.
The California Aqueduct is in #1. HUGE artificial river in a concrete structure. The canal banks are not designed to support the huge tonnage of steel required to span it. The construction costs to reinforce the whole thing would be horrible.
Drain ditches are mud or dirt much of the year, some only filled when active irrigation needs to drain as from rice paddies and orchards. For example, in Kern County they flood the fields to remove built up salt and selenium (“Kesterson reservoir” issues) I used to swim in a big one by jumping off a train trestle into it.. These are often semi-stagnant and the only thing preventing putrefaction is the algae making oxygen. LOTS of cat-tail / bullrush growth in the shallows. Fishing can be OK, but not great. Cover these and you will have cat tails growing up through the panels (they typically go higher than the bank top). During much of the year you will have a dust problem from the plowed fields or dry canal bottom. Every few years you will need to remove them for canal maintenance as otherwise the canal fills up with crap and the weeds take over the banks.
Major Distribution is the best swimming especially around weirs. Expect a lot of local kids looking to use these as diving platforms… Especially at the start and end of the runs. Usually there’s a regular truck route along the canal. Either next to it or on the bank. These are very dusty when you need irrigation water in summer. The guys who adjust the weirs (to send water to the folks who bought it at the right times and in the right amounts) along with the farmer on the land next to it regularly drive these roads kicking up dust clouds. As do kids going swimming, drinking beer, and hunting. Also farm equipment. Orchards expect less production from the trees near the access roads from the thick dust layer on the leaves…. Expect bullet holes. (Pheasant and varmint control are big as is duck hunting). Expect a lot of birds nests in them and expect a big rodent chewing expense. Rodents love wire insulation for some reason… Expect some yahoos to unbolt and remove / sell the panels or put them on their barns. Expect rocks thrown at them (bouncing rocks off the water is a common amusement, bouncing them off breakable things even more so). Your “foundation” will be soft dirt on the banks. There’s a roughly annual weeks long mowing of the banks and every few years recontouring of the bottoms. Don’t know how that’s going to work. Do not expect permission to spray herbicides next to the water going to a farm “somewhere else” growing “who knows what” that the herbicides might kill.
Minor distribution runs all over between the orchards, pastures, etc. LOTS of swimming and crawdad hunting when they are dry. Kids ride dirt bikes in the dry canal off season. I think a huge number of new uses will be found from “Forts” to motocross jumping over the panels… Again there is an annual mowing with a tractor of the banks and a bottom fix up every couple of years. Weirs get regular adjustment too during summer irrigation. These are only about 8 feet wide in some cases so your area will be small. OTOH, you have thousands of rural miles with the nearest home out of sight to patrol for vandalism and theft, so “good luck with that”. At one time rural aluminum railing on bridges was being removed and sold for scrap and copper is always a prime target. Using any Aluminum and copper in those things? Just sayin’…. You have roughly a 40,000 square mile area in California Central Valley alone to patrol and will need officers about every mile to be effective. How many you got? What are their salaries?
Oh, and every so often a farmer out in the field falls sleep on the tractor and wakes up as it climbs the bank. One guy we all had a good laugh about as he got stuck nose into the canal and needed help pulling it back out. The folks driving tractors, harvesters, sprayers, bulldozers and more are often not the most careful, bright, or awake… I only remember about one a decade going into the ditch, then again, most folks didn’t talk about it, just got the tractor back out and pretended it didn’t happen 😉
Finally, there’s sometimes a field of cattle next to a ditch or canal and they will go there to get a drink. What’s your liability insurance situation for loss of cattle stuck in the junk? Or are you going to build kilo-miles of fencing and provide watering facilities on demand?
Bonus Round:
One of my favorite things as a kid was “Frog Gigging”. You take a long bamboo pole with a trident spear on the end and a flashlight. Each person takes one side of the canal and shines their light on the other side at the water line. When you see eyes reflecting, you tell the other guy and he gigs it on his side. Frogs like dark places so I expect gigging at the solar arrays to be good. Plus, when you can’t quite reach the frog you can climb out on them … I’m sure only a few will be broken or have broken connections from gigs and feet and such…
I’ll bet not one of the designers of these things has lived a year in farm country and observed the usage cycle…
The last idea like this was solar panels in the road. Even ‘Treehugger’ knew it was daft…
French Solar Roadway Declared “A Complete Flop”
February 19, 2021
Sometimes we should just let a bad idea die.
https://www.treehugger.com/french-solar-roadway-declared-complete-flop-4856792
Indeed.
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6000 km of this?