[tinco]

GP is just restating the last sentence of the "Significance" section of the paper in harsher words:

"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..

[ianai]

1. I’m not convinced this has to be artificial light as fiber optics might be able to pipe in plenty of sunlight.

2. I’ve heard the real efficiency is tailoring light from high efficiency leds per plant.