Artificial lighting saves land because plants can be grown above each other, but if the electricity for the lighting comes from solar panels, then the savings are canceled out by the land required to install the solar panels. The vertical farm is a paradox unless fossil fuels provide the energy. In that case, there’s not much sustainable about it. This entire piece is based on the assumption that the only sources of…
Right, and more than that, it appears to be relying on the old fallacy that a solar panel takes up "land" the same way a field of corn does, to the exclusion of other uses.
That is not necessarily the case, especially when we're imaging strategic uses of space that might become more prevalent in the future. Solar panels can go on top of things, including other solar panels in the form of vertical solar farms.
If we talked about pages of books the same way we talk about solar panels, you could claim that War & Peace takes up an acre of space.