There are other inputs to growing outdoors: fertilizer usage, water usage, and insecticide/pesticide usage (likely not an exhaustive list). In a controlled environment like an indoor farm the use of each of those is dramatically less than in traditional farming. It would be worthwhile to include all of the inputs of growing food since light and transportation are not the full list.
(disclosure: I work for an indoor, vertical farming company)
Yes, but does the reduction of the other cost win against the increase of cost of illumination? Do you have a table with an estimation of the cost in each scenario?
Some back of the envelope calculations: From [1] the cost of fertilizer is like $150/acre and from [2] you can get about 7 tons/acre, so it's like $40/ton. The numbers change a lot from source to source, so let's multiply that by 2, and we get $40 of fertilizer per ton.
So in the impossible best scenario where the indoor production saves you the 100% of the fertilizer, you save $40 per ton of fertilizer that is much less that the $3000 per ton of electricity for illumination.
Even if you go full renewable fertilizer, and run Haber-Bosch process with electrolysis-based hydrogen and electricity as energy source (instead of natural gas which is currently used for both), you’d still increase the price of fertilizer by a factor of 5 at most, not getting even close to the cost of artificial illumination.
There are other inputs to growing outdoors: fertilizer usage, water usage, and insecticide/pesticide usage (likely not an exhaustive list). In a controlled environment like an indoor farm the use of each of those is dramatically less than in traditional farming. It would be worthwhile to include all of the inputs of growing food since light and transportation are not the full list.
(disclosure: I work for an indoor, vertical farming company)