I doubt the size limit would be removed. Even if the system is installed by robots, it's presumably going to be maintained by humans. If a panel dies early or gets damaged, you want to be able to swap it out. There are also economy of scale benefits for maintaining a common architecture with other solar applications, like rooftop installations.

The pannels really are roofs. We are building roofs without homes under them.

Not really. They aren't water tight. You can get solar roof tiles but they're more expensive than traditional panels.

Rail systems could and if you look for it, already do form gutters along the panel-to-panel seams to not drip water inside the contiguous array area.

Still cheaper than a metal roof intermediate layer, though. But in places like Germany overhead glass outside of some limited applications (notably greenhouses for farming) isn't allowed to drop on anyone's head just from a sharp pebble impacting and cracking a glass layer. Sadly the regulations are just as strict for a home carport/garage-without-door as for a majestic train station hall. So aside from the worse cooling it's in practice cheaper to just use a corrugated sheet metal layer to catch rain and falling glass, with the structural support for both unified.

For us, we're happy for modules to get quite a bit bigger since the time it takes to build a bay (what we call one assembly of a few modules on a metal tube) is approximately proportional to the number of modules, so bigger modules => fewer modules => faster build times. Our robot arms could handle much larger modules.

For traditional human installation, we're already approaching the limit of reasonable module sizes -- today's modules take two people to lift and align.

Can you not prefab larger modules from smaller modules off-site?

> Modules for solar farms have been getting larger and heavier, but the maximum size/weight has traditionally been limited by what human workers can heft into place.

Are there installers that actually use humans to lift solar panels onto racking on solar field projects? I figured everyone was using vacuum pump panel lifters instead of humans these days as it’s much faster and less prone to injury.

One example: https://unimove.com/lift/solar-panels/

These can easily be fabbed up by a single person, it’s just some steel and a couple vacuum pumps.

I'm trying to find recent Time Lapse videos - here is one from Australia, 2020 - at the time the largest in Western Australia - so at scale. All the panels were hand lifted by one person. https://www.youtube.com/watch?v=uCtFG-hIHdM

Ahh - better - here is one at scale from a year ago. https://www.youtube.com/watch?v=72UlzbsON4M

West Texas:

  - 200 MW
  - 1200 Acres
  - Piles -- 68,350
  - Support Piles  (Crew does 80-100 piles/day)
  - Tracker System
  - 490,150 Solar Modules
  - 540 watts/module
  - Crew can install 500 panels a day
  - These are multi person 2-4 people lifting.
  - 500 workers on site - doing 6200 panels/day.
  - (That suggests ~40 person crews if all worker installing 
  panels.   Wow - now I see why this is a big deal)
  - Cables panels -> Inverters
  - Big Inverter install to to convert to AC
  - Lots of concrete pouring for substation/Inverter Pad.

I would imagine that the next constraint in the size would come from the supply chain, so you'd probably end up seeing panels that are 4'x8' if human liftable weight wasn't a consideration.

Perhaps the next size up would be the interior dimensions of a cargo container so they could slide in/out like sticks of gum.

The limit is often what you can put on a road.

Eventually a blimp