This month, IEEE Spectrum considers “The Green Promise of Vertical Farms” [1]. Harry Goldstein examines “Indoor farms run by AI and lit by LEDs can be more efficient than field agriculture, but can they significantly reduce greenhouse gas emissions?”
Contemporary indoor farming has many potential advantages: reduced pesticide use, efficient use of water, reduced transportation costs, jobs. There are quite a few variations on the theme, but they all amount to trading electricity for food. The principal input to the controlled environment is artificial light and HVAC, and in some cases, water purification.
The upshot is that the economics of these operations is dominated by the cost of electricity. To date, this has meant that high value crops such as leafy vegetables are cost effective, but bulk crops such as grains would cost too much to be competitive with outdoor growing.
Another upshot is that the overall environmental impact depends on using clean energy. Conventional agriculture is a major source of greenhouse gasses, as well as water consumption and habitat destruction. But moving production indoors requires huge amounts of electricity, which generally emits as much or more Carbon as the outdoor agriculture. Indoor agriculture can potentially be significantly greener, but only if sufficient renewable energy can be generated.
While it is possible to install vast amounts of renewable energy generation dedicated to indoor farming, this is far from a done deal. For one thing, farming must compete with every other use of power, including transportation, manufacturing, and home use. Outdoor agriculture certainly has the advantage of directly using solar power, without expensive engineering.
In any case, outdoor farming is vast and sprawling. It would take tens of thousands of skyscraper farms to replace significant factions of conventional agriculture.
I’ll note that this would be replacing well tried, simple solar technology–i.e., plants growing in a field–with complex and iffy solar technology–i.e., electricity generation, feeding complex robot factories, operated by algorithms. Stated that way, it’s not surprising that outdoor agriculture is hard to compete with this way.
On the other side of the balance sheet, there are advantages of urban farming in general, including local food production and jobs. Indoor farming can pay important dividends by improving the life of city residents, regardless of the Carbon balance, if it delivers better food and a better life to the people of the city.
However, many of these benefits of urban farming depend on how the farm is operated. Corporate farms with a handful of employees do not provide many jobs, and do not much improve the self-sufficiency of the city—especially if they focus on supplying luxury foods to expensive restaurants. Installations that produce extremely expensive specialty crops do not necessarily impact the overall food needs of the city. To the degree that the farm serves a small, wealthy elite the boon will not trickle very far down.
Hyperefficient indoor farming per se does not necessarily impact many important aspects of food delivery, either. While locally sourced vegetables will be fresher, they will be just as subject to food waste and unequal distribution unless the rest of the delivery system also changes. (Hint: “food insecurity” and “nutrition deserts” are not referring to a critical shortage of Kale and fresh salad greens.)
In the context, I note that the success of the ‘farm on the roof’ in NYC has everything to do with how they connect to their local community, and little to do with Buck Rodgers technology (of which they actually have very little). And, yes, they do sell fancy fresh veggies to restaurants—but they also are good neighbors.
The point is, the challenge of sustainable urban food supplies cannot be solved by LEDs and AI, at least not alone. And to the degree that the focus is on building large scale commercial operations, rather than human communities, it is probably not helping solve the most important problems.
So, I would suggest that digital wizards cast their eyes on ways to enhance neighborhood food production and distribution. Ideally, the algorithms should be optimizing for food security and healthy people, not for “disrupting” farming.
- Harry Goldstein, The Green Promise of Vertical Farms, in IEEE Spectrum – Energy. 2018. https://spectrum.ieee.org/energy/environment/the-green-promise-of-vertical-farms
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