Sure, sun and rain are free, but the costs for outdoor farming are huge too. Irrigation, pesticides, fencing, harvesting equipment, anti-weed chemicals. Then your yields are super volatile -- weather can be bad, you can just get unlucky, you can have weeds/bugs/mice eating into your yields. Then you need to get your crops all the way from Montana to big markets hundreds or thousands of miles away.
Indoor farming sure does require an input of energy and a high up-front cost, but you can get extremely high yields reliably, and you can dramatically reduce transportation and chemical costs, plus reduced water costs often.
Those costs are known, and outside of California and Nebraska, almost no crops are irrigated.
As far as transporting crops to markets? That's actually a success story. Rail hauls most of the crops from Montana to the PNW (if exporting to China). Rail is dirt cheap and efficient, as any true HN reader will know. :)
For context, the "almost no crops" that are irrigated comprises about fifty-five million acres, a little over 7% of cropland & pastures. Removing pastures from this data is difficult, but since we're only looking at three hundred million acres primary cropland in the US, we can confidently approximate between a tenth and a sixth of primary crops are irrigated.
I believe around 50% of that 55M acres are hay/forage/pasture. Nebraska and Colorado are easily top players. I underestimated the delta. Point remains there isn’t a ton a irrigated production for commodity crops (corn/soy/wheat/cotton)
Do you know if things like sprinklers count as irrigation? I grew up spending a lot of time in Delaware which is tons of farmland, and I remember seeing lots of weird watering devices and sprinklers.
Indoor farming sure does require an input of energy and a high up-front cost, but you can get extremely high yields reliably, and you can dramatically reduce transportation and chemical costs, plus reduced water costs often.