45% of the light is in the photosynthetic active wavelength range in a normal farm vs ~20% solar panels w/ transmission conversion losses etc + 40% LED = ~8% of the incoming light is now useful for photosynthesis.

So, you need a huge increase in efficiency ~400+% just to break even.

PS: Not that their using solar power, but it's still worth considering.

PS: They have had rice subsidies over 700% and it's still not cost effective to convert more forests to farmland. Growing food in doors works due to subsides but it's hardly necessary.