Edit: Citation: https://www.youtube.com/watch?v=7bdkcoiFaN0
They're hoping to add a 250MW power plant which would be a major change but that would be part of a different environmental assessment.
They raised a howl because the plans say they will start on a power plant, whose impact is considered -- but 'oh my goodness, where will the gas come from? A well? Trucks? Oh my!'
Well -- that literally may not be known yet, as is when and whether they'd get close to running it at anything like capacity.
And that's not a problem; Texas has power plant regulators, and pipelines have their own paperwork and process.
The FAA regulating this is a bit funny anyway. :) Eventually that'll change, but right now they're doing a good job handling these weird corners of their responsibility with grace.
These projects usually take many years and Tesla tried to basically do it in one and is annoyed that it is stretching out to two.
In the big picture 2-3 years to get a new large auto factory online is pretty normal. There are definitely some parallels to SpaceX in Boca Chica, TX. They both are hitting regulatory delays, but stepping back it seems they are the result of intentionally trying to "move fast and break things" with their development timelines.