> Who says you need to replace it? Solar, windows

Windows? So a semi-transparent layer to help isolate the farm from the elements? Kind of like a greenhouse? That thing that existed for several hundred years.

> I’m sure there’s plenty of ways to use the sun’s energy.

Solar panel to Inverter to Battery to LED lights is just a way to throw away some of that energy. Sure, you're still using it, but a LED is never as efficient as sunlight.

Do you get the core concept of vertical farming? It’s just stacked layers of farmland. Greenhouses cannot pack as many layers vertically. It’s pretty straight-forward.

If you’re strictly optimizing for just sunlight then sure, greenhouses sound fine. But there’s more factors at play here - like the cost and availability of land now and into the future.

The sunlight incident on a vertical farm is the same as would be incident on a regular farm. Having windows or fiber optics doesn't make up for that, especially because anywhere it would be worth it to have a vertical farm, it would be worth it to have other tall buildings.

In addition, if you are making up this energy with solar power, you've negated the land use advantage.

Yeah. The only way vertical farming could make sense would be with crops that usually get much more sunlight than they need. Even then, if it's a crop that allows to use machines with massive throughput in conventional farming - vertical farming would need something similarly cheap, too.