Vertical farming, the best solution to support an ever growing population or just a scam?
IMHO it has a lot of potential but not being able to grow grains really is something that should be tackled sooner rather than later. But I could see this being used by self sustaining communities to provide lots of food while using very little space. And it's technically more environmentally friendly than just using vast stretches of land to produce the same amount of food.
The notable thing about highrises is a small solar footprint, and you need to have ownership/rights to install on the roof.
If you have that much space for solar panels, then maybe a traditional grow would be better than urban vert farming
I am not saying that this is necessarily a good idea, but it is technically possible to grow more plants with solar panel + LEDs in the same area than through direct sunlight illumination. (IIRC by almost 200%).
The added complexity and manufacturing may not be worth it, but the calculation can be different where your energy is cheap and abundant through other renewable means that have lower footprint (like hydro or wind).
It can also be really good in areas where the climate isn't great for year round growing, with enough PV you'll still get enough to power the LEDs which you can put close above the plants and have on for 17 hours where as the natural sun might not be as bright or steady, also if you have like a wall unit inside then you don't need to worry about frost, slow growth due to cold or hot weather scorching. Having herbs growing inside really improves the quality of a room too, that fresh smell is nice.