But Photovoltaics is only one method. There's also hydro and geothermal and wind. (Which yes, I know are indirectly from the sun.) Having electricity->lightbul

But Photovoltaics is only one method. There's also hydro and geothermal and wind. (Which yes, I know are indirectly from the sun.) Having electricity->lightbulbs->plants means separating oneself from the standard growing cycle, along with all the elements of growing outdoors. Being outside of the growing cycle means you could have different climates in a single large building. And having enclosed buildings for growing means being relatively immune to insects, invasive plants, mold, fungi, and other nasties that can wreck havoc on your crops.