Comment by XorNot

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...