Vertical farming is a pipe dream.
If we do that it would nice to have some experience ready to go on the Industrial farming side.
Also it takes protons to haul the wheat to market, to harvest it, til the soil and plant it. Not to mention all the externalized costs of large scale outdoor agriculture.
Also on mars and the moon beckon, having a closed loop there would likely dwarf anything we can grow on a field here because of the energy costs of moving tons of food into space.
"However, given the high energy costs for artificial lighting and capital costs, it is unlikely to be economically competitive with current market prices."
There is a limited amount of sunlight hitting an area. That means to scale crop yields by going vertical, you need artificial light.
At the moment energy is not harvested in a (sustainably) scalable manner, so vertical farming is infeasible except to boost local production in rich countries.
Saying it's a "pipe dream" is a bit too harsh imo, I think as energy demand ramps up, and oil keeps going down eventually we will be forced to produce unlimited amounts of cheap energy through nuclear power plants, but that's just my vision for the future..
2. I’ve heard the real efficiency is tailoring light from high efficiency leds per plant.
And that would be true, but it could still be a good target within an order of magnitude, because it could be set up as a very big RAID array. There would losses due to cooling and power and space between the drives and whatnot, but to a first approximation (Facility Volume / 1Tb density * 50% fudge factor) will be pretty reasonable; especially if someone really tried to engineer clever heating solutions.
So the paper gets (checks) ~1,300t/ha lab conditions. Why, in theory, can't they just replicate the lab environment as many times as fits in a big facility? I can see practical impediments like cost, I can't see theoretical ones if it is decided that This Must Be Done. I'd expect reasonable yields of 650 t/ha. That improves on 17 t/ha farming practice [0]. Point is that sort of calculation is totally routine when looking at academic results and I don't see what the problem is using a 3'x3' lab environment then extrapolating with a fudge factor.
As a complete outsider, I say scale it out rather than complain! I eat chapati every day, so I am biased towards wanting success to occur.
It is always possible that endeavors will fail.
"Those who say something is impossible should get out of the way of those who are doing it"
Light, nutrient and water distribution can be replicated, but making sure things scale properly and you don't get cascading failures is key.
I can understand the argument "it isn't economic", but the process to make something economic is do it once -> do it many times -> do it many times cheaply, so the paper could be part of the process that ends with mass vertical farming at absurd yields.