Even if it's possible to squeeze three times more money for the actual plant growing, I'm not sure it will make a dent on the difference. From the energy perspective: highest possible solar cell efficiency is around 30%, which means just this particular step in the chain will already eliminate the upside of local produce. We still have to account for batteries, LEDs, transmission lines, heating or cooling of the farm, and pumping water and nutrients around. The numbers just don't add up for "large-scale" staple crops like wheat or soy.