Are Vertical Farms the CleanTech Future of Agriculture?
In the past few years, the Vertical Farm Project at Columbia University has become a minor cause célèbre in the worlds of urban planning and sustainable agriculture. Since this summer, it has been featured in The Huffington Post, The New York Times, Popular Science, and most recently Scientific American. The project’s founder, public health professor Dr. Dickson Despommier, has also been interviewed on the Colbert Report, which led to some polite ribbing as well as an explosion of traffic on the project’s website.
So what is it? Basically, you can think of the Vertical Farm as the ultimate in local food production: a one-block urban skyscraper, with each floor dedicated to producing a different food staple. For the bulk of the plant crops, controlled environment agriculture would be employed in order to maximize production levels per square foot. Lower floors would be used for raising domesticated animals such as chickens and cattle, and organic waste products from both animals and plants would be composted for electrical generation and soil amendment via methane digestion. This combination would – theoretically, at least – make a vertical farm energy and resource independent. The Vertical Farm planners claim that a single such unit could provide enough food for 50,000 people annually.
The real issue: land conservation
The idea of the vertical farm was impelled by concerns over resource conservation and food security. With the Earth’s population expected to reach 8 billion by 2025, modern-day intensive agriculture will be hard pressed to produce enough food without a major technological innovation. Most industry experts believe that innovation will come from the realm of bioengineering; however, that innovation has yet to arrive, and in any case intensive agriculture is not without major environmental problems of its own. And while the organic and local agriculture movements show some potential for solving these problems, one they cannot solve is the finite amount of readily available, arable land.
Enter the vertical farm. Despommier and his colleagues argue that the real crux of the issue is land conservation; even if we could switch the whole world to ecologically perfect farming practices overnight, there’s still the problem of a rapidly growing population in a limited area. The vertical farm would solve this problem by expanding farms upwards, rather than outwards. By moving food production far closer to the end consumer, Moreover, growing food indoors would allow for certain efficiencies not attainable by traditional agriculture. For instance, the use of hydroponics would allow for recirculation, enabling farmers to conserve massive amounts of water, and eliminating the problem of fertilizer runoff. Best of all, all of the technologies employed in a vertical farm – hydroponics, controlled environments, water recirculation, methane digestion, etc. – are already mature.
Some unresolved issues yet remain
The major obstacles to vertical farm development are mostly economic in nature. First, although Despommier and colleagues have argued that a vertical farm could be a profitable business, the level of risk is quite high. The capital investment ($150 million at the very least) is huge, and given the Byzantine nature of the food distribution system, it is not entirely clear how the goods would get to market. This in turn could make food storage into a problem, as the planners have thus far assumed storage needs to be minimal. Moreover, zoning restrictions ensure that a true vertical farm would have to be located in an urban center, which means competing with office buildings for space. It also raises numerous food security issues of its own – would a vertical farm have to require government-level security to protect against terrorist activity and other threats to the food supply?
There remain major environmental questions as well. Although the planners have claimed that a vertical farm would be a net producer of energy, this has not yet been empirically proven, and even Despommier admits that their energy usage estimates may be overly optimistic. It is clear that vertical farming is environmentally inferior to traditional agriculture in at least one respect: most plants in a skyscraper farm will necessarily have little if any access to sunlight. Providing 24-hour lighting in such a unit will require a tremendous amount of electricity; while the planners claim that this will come to 26.5 million Kw/h per year, there is good reason to think it could be actually be much more. A controlled environment will add considerably to that total, and even if the building is LEED standard the energy required for cooling and heating will show considerable variance depending on local factors. Greenhouse growing also requires a great deal of ventilation in order to be efficient, and it is not yet clear how best to design a skyscraper that meets this requirement. Finally, the planners’ assumptions for animal husbandry are closely modeled on industrial farms, which have come under intense fire in recent years for inhumane practices.
A final (critical) evaluation
Personally speaking, I love the vertical farm concept, but I am deeply skeptical that it will ever be successful, at least not in the ambitious form Despommier and his colleagues have envisioned. Controlled environment agriculture has always been an energy-intensive project, and I doubt that the additions of animal husbandry and methane digestion can make it energy self-sufficient. I also think the real estate costs and logistical challenges may be insurmountable. But the vertical farm has a spark of imagination behind it, and may ultimately inspire another, more feasible model.
Watch the interview with Dr.Dickson Despommier on the Colbert Report.