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.

> 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.

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...

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.