That's not factoring in that the field in Salinas has to use much more water, use pesticides and fertilizer, and tilling and harvesting, which all require more energy than the local hydroponic garden.
Of course the environmental cost should be factored in. I'm still curious if hydroponics (or geoponics, in this article's case) actually winds up having a better carbon footprint than traditional agriculture.
Couldn't some of the gains of indoor vertical farming be gotten with greenhouses? Namely protection against pesticides and minimal water loss from evaporation.
The whole premise of a 'vertical farm' seems bunk to me for this reason. If you want ultrafresh local food in a climate which doesn't support it, with precise control over the growing conditions.. well that's precisely what greenhouses provide. A 'vertical farm' is what you get when you make a greenhouse worse by removing the windows for no real reason, then try to compensate for that with futuristic vibes. Put a greenhouse 15 minutes outside the city and you'll save money with cheaper land and free solar power (greenhouses may also have supplemental lighting or heating if needed.) You get all the freshness advantages of local production, but cheaper. The only 'downside' of greenhouses relative to vertical farms that I can think of: greenhouses are old technology that won't make yuppies feel like they're living in a sci-fi movie.
IIRC in a documentary about spanish produce vs german greenhouse produce they calculated that german produce is much higher in co2 output than spanish, even when the spanish produce is delivered by a semi all the way from Spain! Simply because in spanish climate there is no need for a greenhouse to grow e.g. bell peppers or tomatoes.
I only found a german source: https://www.umweltdialog.de/de/verbraucher/lebensmittel/2015...
it says:
German, heated greenhouse outside of season: 9.3 KG of CO2 per KG tomatoes (well, that is unexpectedly high)
Non heated greenhouse: 2.3KG of CO2 per KG tomatoes
open land in spain: 0.6KG of CO2 per KG
open land in Germany in season, conventional: 0.085KG of CO2 per KG
open land in Germany, organic: 0.035KG of CO2 per KG
although it's from 2015, I don't think that much has changed in 5-6 years to make up such a big difference between heated, nonheated, open land and regional. It also factors in transport from Spain to Germany which is why open land in spain has a higher co2/kg than german open land.
edit: of course I can't find anything that compares vertical hydroponic farming to greenhouses, all I can find relates to CO2 dosing in greenhouses :/
It's less helpful in already highly agricultural nations like the US, but in countries with scarce arable land or fragile ecosystems, or just very small countries like Singapore/Cambodia, vertical farming is superior to greenhouses simply due to square footage
The economics only make sense for specialty things like fresh greens, micrograms, mushrooms, etc. That can't be farmed at a consistant high quality year round or be stored. It will never be economical for 80% of food.
I believe greenhouses and vertical farming are orthogonal. IOW, you can have a vertical farm inside a greenhouse, or a "horizontal" farm inside warehouse with grow lights.
Of course the environmental cost should be factored in. I'm still curious if hydroponics (or geoponics, in this article's case) actually winds up having a better carbon footprint than traditional agriculture.