What California is learning from solar panels built over irrigation canals

Yeah sure, let’s put solar panels over the last section in Bakersfield where all the canals merge. More power, less evaporation. That’s great! But it’s not going to move the needle in California.

* if you go backpacking in the Sierras you’ll often run into one of the canals. They’re both cool and scary. It takes hours to get to them and every time I see one i have to wonder how they managed to build it (it’s been decades so any construction damage has mostly grown over)

Nothing short of a face-to-face security response will deter these criminals, so there it is a challenging cost-benefit balance. At least panels in parking lots and other developed spaces have the benefit of witnesses. I'm sure a 20 foot climb up a steel beam over running water is a decent deterrent as well.

No because now you're using land that could be used for other things, which is exactly what this avoids. This takes existing land that loses water and costs money, and makes it lose less water and make money.

That aint' gonna fly - you're going to have engineering requirements for a 100' span wither it's a shade structure or a solar panel. And don't even think about fabric shade sail types of things, nobody is going to want to replace those every 3 years.

>it takes 1/6 the time to build on developed land compared to undeveloped land.

This is not something you can just ignore

I would very much like to see a total dollar figure for the example "roof trusses over the canel" structure vs. how many panels it can hold.

It's already true that the ground mounting costs and labor to assemble the ground mount are a huge part of building a large scale PV system.

Almost all the fields in the area is being used for valuable crops. It would be difficult to harvest them if solar panels were installed.

The wind on the valley side of the coastal range is intense. A cheap shade will need considerable maintenance.

There is little chance two separate projects would be cheaper than a combined project.

They paved paradise, put up a solar array.

The supports in the picture are massive and don't look cheap.

They're load-bearing.

... likely less than the ~$13/W this cost to install, but that included NRE for three different styles of panel mounting. Standardizing would cut costs significantly.

As the earth moves the sun would only hit one side and lose efficiency but right now it's "free space" not being used otherwise

They even make flexible solar panels now that can bend and move with the wind and don't need a stiff frame, slightly less efficient but volume makes up for that

Clean them the same way automated window washers work on skyscrapers

Shame they never came up with the solar paint solution, yet

This is one reason I now live in Nevada, where pretty much everything is legal...

https://valleycleaninfrastructureplan.com/

In this context, covering canals reduces evaporation in addition to effectively being free space for solar PV; if the labor and material costs are reasonable, the land is free forever versus a land lease for ground mount utility solar. As of this comment, there is ~101GW of solar in California’s grid queue pipeline per https://www.interconnection.fyi/?state=CA

Is this enough solar? Just keep building. Enough sunlight falls on Earth every ~30 minutes to power humanity for a year.

https://www.eia.gov/energyexplained/solar/where-solar-is-fou...

Yes, absolutely. But if you try and do that kind of stuff and the regulators show up and kick you right in the dick. "You got a permit to put panels on this land?" "Where's your SWPPP?" "Where's your environmental impact assessment for shading that canal?". And HN cheers.

But if you say you want to cover the canal with solar panels out comes the rubber stamp because that's what the powers that be want to "incentivize" this week.

Does the success of populists make a little more sense now?

I seriously doubt that you can chain even 1/4 mile of panels together without destroying things. Thats already puting thousands of volts and hundreds or thousands of amps through the silicon. If you are making it all parallel you still need wiring between panels that can handle that. The cabling doesn't go away, it just moves.

Wouldn't there still be supports in a feild of solar panels? Are you sure that those supports + the supports for the shade material are going to be less material than the supports for this?

Most shade material wears out pretty quickly. Will their replacement result in more expense, more waste, etc than just putting the solar panels?

Shade material is generally pretty heavy, is it really going to need significantly less robust support? Weight aside, how much of the load those supports are rated for is due to the actual weight of the panels, and how much is for forces from things like wind?

Unfortunately it’s the reason California has the highest price for electricity in the country as well (not counting Hawaii). Looks lone they are paying ~$0.34/kWh, ouch. The average is ~$0.15/kWh in my state.

I was shocked when I saw how much batteries contribute, honestly don't hear about them much but they have scaled a lot in recent years.

this part of the claim is carrying a ton of weight here... Zero-carbon sources could include carbon dependent sources with paper offsets.

Good questions I guess but what more specifically are you saying would happen if we delete the canals? What does "the water infiltrates the ground and stays hydrated" mean?

Presumably deleting the canals means water will still be relatively scarce and the distribution will simply by different and not controlled by the state.

Every plant built would give us a much needed buffer and in the good times could even let us refill ground water (we'd never do that, I know).

https://www.youtube.com/watch?v=x-RGL15Skuo

Are there risks of heavy metal and tire contaminates from vehicles leaking into the water system over time?

Are there risks of dust blown contamination from the megatons of shit humans leave everywhere we go leaking into the water system?

The answer is everything has risks, the risks from solar panels are unbelievably tiny in relation to all other pollution sources and I have to deal with a bunch of redneck solar panel haters that have bought in to massively overblown risks around them.

https://www.nature.com/articles/s41893-021-00693-8

https://sci-hub.ru/10.1038/s41893-021-00693-8

But more importantly it found that these solar panels are replacing diesel generators that pose a much larger pollution risk so water quality actually improved.

> The duo went on to start Solar Aquagrid, an advocacy firm dedicated to reimagining aging canals, and partnered with the Turlock Irrigation District, UC Merced and the California Department of Water Resources to cover small sections of Turlock’s canals with solar panels. The new “solar canal” provides shade to limit evaporation and generates power all in one neat package. They call it Project Nexus, and it operates at the intersection of the state’s need for clean water and energy.

> ...

> But the canal site hosts more than just panels. Bales said they “have instruments out there to measure temperature, relative humidity, wind speed, incoming radiation, outgoing radiation, and a prototype instrument to measure evaporation directly.”

> When it comes to algae, the panels helped. “Last year when we drained the canal at the end of the irrigation season, there was a physical line on the sun side of the canal that had algae growth and then not algae growth from where the shade was,” Weimer said.

That it's green energy and can help supply the power demand is a bonus.

Fair. But the almonds and alfalfa would like a word, especially since the alfalfa is shipped around the world for others to consume in some way.

So while it's definitely agriculture as a serious source, it's not just the US as the driver of that source.

No thanks

A 450W solar panel will make roughly 562 kwh a year in California.[2]

So one panel running for one year offsets 140kg of steel production, roughly.

Thats an I-beam based structure so it's weight efficient and a heck of a lot more then 1 solar panel are going to fit on it.

Judging from a local steel supplier[3] and some span tables it looks like you'd need about a 360mm or so I-beam to bridge a 115 ft (30m) channel (the structure looks more efficient then that though) so call it 50kg per meter. So one span is probably ballpark 1500kg of steel.

A 450W solar panel is about 0.7m wide, the structure is fully covered so call it 42 panels per span offsetting the energy production of a little over 5900kg of steel per year (and it doesn't look like we're putting one solid I-beam per row of solar panels either since I see lightweight spanning channel in there).

[1] https://solar.lowtechmagazine.com/2009/06/how-much-energy-do...

[2] https://www.cahomesolar.com/feeds/blog/solar-panel-energy-pr...

[3] https://www.mascotsteel.com.au/wp-content/uploads/2018/10/st...

So yes, in fact this does generate far more energy than goes into its production.

While I agree those steel supports are large, that seems insanely wrong to me, but not an expert so curious if someone with more info could comment.