Anecdotally speaking, I have heard of a massive California solar farm in an undeveloped area that has serious vandalism problems. Junkies will find ways through the fencing at night, strip copper and other materials from panels, and cause thousands in damages and lost energy just to extract enough scrap for a fix.

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.

> It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no?

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.

My understanding is that "The best reasoning they give" is the entire point. It such a huge issue that it drowns out all of the valid but smaller issues you are pointing out. And, the benefit to the water is just a bonus.

The cost of building that steel structure that will hold up against maximum in 100 year wind forces isn't cheap. Large PV panels make very good sails. The trusses look basically the same as you'd see in a large agricultural barn, horse riding arena, etc. Putting the PV panels on empty bare land at a height people can walk around and work with would be considerably less costly.

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.

How about hanging solar panel vertically on tall buildings covering every floor except the first few to prevent vandalism

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

What's the lifetime of a "cheap shade"? And the cost to renew it over the same lifetime? And the cost of paying for other land?

... 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.

>It seems like it would be more effective to simply put all the solar panels in a field, and construct a cheap shade over the entire canal no?

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 this land?" "Where's your environmental impact assessment for shading that canal?". And HN cheers.

But if you cover the canal with solar panels you get a lot less of that bullshit.

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

Or better yet, invest in pipes.

There are solutions like this to most of Californias big intractable problems, and they're not done because some California laws and/or regulations make it impossible.

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

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Power lines are made of aluminum and steel.

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?

They don't mention Gujarat specifically, but they do mention the prior projects in India and Arizona (which your link discusses) in the article.

You need to credit someone for "hey lets use solar panels to shade things that would benefit from shade"?

This hacker entered the thread thinking this was a good idea but leaves muttering “man, things are complicated.”

Maybe, but ideas like that are what you all will use to eventually turn against solar and seek to ban going off grid as you see a disparity between those who can afford to buy solar and those who can't. Why's that a problem? Those who can will go off grid and those who can't will be left on a grid that they can't pay for, and it will crumble. We are already seeing the beginnings of this in California.

I thought this was a pretty awesome video to provide the lore on how water got to Southern California. Growing up in Pasadena I heard the name Mulholland and Eaton (as in canyon) all the time but never realized they were so instrumental in the founding of the city and all the wild shenanigans that went into getting the water from up north to LA.

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

Electricity is incidental (and a nice benefit) to the goal of "reduce evaporation of water from the irrigation canal and improve water quality".

> 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.

> Lastly, the US has got to start eating seasonally.

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.

Steel takes about 4.750 kw-hours to produce per kg.[1]

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...

> I doubt those panels will ever harvest enough energy to offset the energy use to produce both the cells and supports.

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.

According to my searches, steel production is something like 6-8 MWh/ton to extract, refine, and shape. A solar panel lasts 25 years at up to 80% effiency. This thing produces 1.7MW at peak. so call it 3 MWh/day average to account for a lot of adverse conditions over the lifetime. Thats 27000 MWh... so unless we are looking at more than 3000 tons of steel (we aren't) the steel production is accounted for. A panel takes something like 1.9 MWh equivalent in energy.... and again we aren't looking at 13K solar panels in this pilot.

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