Not sure if it's still the largest, but this plant is a few hours drive away from where I live in Phoenix:

https://www.forbes.com/sites/uciliawang/2014/04/29/behold-th...

That's 2400 acres and it's up and running - so I assume permitted and connected to the grid. But I don't know the the total cost to compare things - I'd assume rather cheap, because Yuma is...not a "destination" (outside of maybe a stopover for the dunes).