Vertical farming has been attracting a blaze of publicity in agtech, from $60 million in investment to an increasing number of vertical farming incubators. Vertical farming’s intentions are noble, but do its benefits stack up?
The term ‘vertical farming’ was coined by Dickson Despommier, a Microbiology and Public Health professor at Columbia University. Concerned with the vulnerability of the food supply due to severe weather conditions, growing urban populations, and far shipping transit for food, Despommier began to explore the idea of raising crops indoors. According to Despommier, “by 2050, nearly 80% of the Earth’s population will reside in urban centers” and conservative estimates suggest that “the human population will increase by about 3 billion people during the interim.” A decade’s worth of Despommier’s students were tasked with researching and developing an indoor agriculture system.
Vertical farming is practiced in urban buildings such as warehouses implying no further degradation of cropland or destruction of existing ecosystems. Its indoor nature is so highly controlled that the “need” for chemical pesticides is almost non-existent. Beyond these benefits, the output per acre is directly proportional to the number of stories being grown, resulting in a more efficient method of land use.
While vertical farms operate on lesser inputs such as fertilizer, pesticides, water, and farm equipment like tractors and irrigation, they require a different type of capital intensity. The nature of a highly controlled indoor growing environment requires a plethora of electricity for lighting, cooling, heating, ventilation, and humidity control mechanisms.
Louis Albright, the director of Cornell University’s Controlled Environment Agriculture program, broke down the cost even further by examining carbon cost, area, and financial cost to grow wheat, tomatoes, and lettuce using vertical farming methods. Since the majority of the American diet consists of grains and cereals, we will focus on the electricity cost of baking a loaf of bread using only electrically-generated light .
Dr. Albright uses indoor wheat growing estimates from a light controlled NASA study of 2 kg per square meter per harvest with four harvests a year. These are generous estimates considering that the world record for outdoor wheat production is about 1.7 kilograms per square meter. Let’s get started!
- 8 kg per square meter per year total at 55 moles per square meter a day (20 hours of full light).
- A year’s worth of light would be 20,000 moles per square meter.
- 400 watt HPS bulbs or LEDs produces 3 moles per kilowatt per hour
- Which means we need 6,667 kilowatts per square meter a year
- Assume electricity costs $0.10 per kilowatt-hour,
- Electricity cost = $667 per square meter a year
- 1 kilogram of wheat makes 3.7 loaves of bread.
- Which means we can produce 29.6 loaves of bread per square meter a year
$23 per loaf for electricity
Looks like I will finally be cutting back on the carbs!
Albright’s butter lettuce carbon cost breakdown (using mass, productivity, and carbon dioxide per kilowatt) found that 8.05 kg of carbon dioxide is emitted to produce one kilogram of butter lettuce.
Think of it in these terms: the average passenger car produces 4,700 kilograms of carbon dioxide year. According to the USDA, the average adult should eat 5 vegetables a day . One cup of lettuce is equivalent to one serving of vegetables. There are 5–6 cups per medium lettuce head, so in theory, one head of lettuce meets the average adult’s daily dietary needs for vegetables. The same amount of carbon dioxide an average passenger car produces per year would only be able feed the equivalent of 7.9 people their daily recommended amount of vegetables in lettuce for a year.
The initial release of green, sustainable technologies is usually expensive, but the real problem lies in the carbon dioxide intensive makeup of our energy grid. The current energy grid has not fully adopted renewable methods. In the U.S. only 13.44% of domestically produced energy is currently renewable, but according to the Renewable Electricity Futures Study, the U.S. has the ability to generate 80% of its energy from renewable sources by 2050. In this context vertical farming would most certainly work from a financial standpoint in countries that have largely renewable sourced energy grids. Unfortunately at this point in time, the climate cost associated with vertical farming far outweighs conventional growing methods, even when shipping emissions are taken into account.
Certainly many of the problems surrounding conventional agriculture could be eliminated through the adoption of vertical farming methods. However, adoption as a global agricultural practice would be unfeasible, let alone a mistake. Much like the Green Revolution, vertical farming promises to increase output and yield per acre, bring standardized, mass produced agriculture to areas previously thought unfit, and decrease the need for physical labor through mechanization and technological inputs. On these promises, the Green Revolution certainly delivered and so too, it appears, will vertical farming.
The current sustainability predicament with conventional agriculture is directly a result of the Green Revolution. The Green Revolution promised to end world hunger, but actually created a food system that is comprehensively unsustainable and destructive. It prolongs the dysfunctional, paternalistic relationship between the global north and south. This application of modern colonialism promotes an unrelenting reliance on growing expensive inputs such as patented seeds, fertilizers, and irrigation resulting in a never ending cycle of debt. Starvation and famine continue to ravage the global south while destroying the planet and facilitating a widespread obesity epidemic in the north.
The bold claim that vertical farming will alleviate hunger as a silver bullet technology is balderdash. Its outrageous start-up costs along with the inordinate financial and carbon operating costs make the technology inaccessible to the populations who suffer the most from hunger. Poverty stricken areas like developing nations have the highest incidents of food insecurity. Despommier is not wrong that cities will experience rapid population growth within the next few decades, but the problem is that almost all urban population growth in the next 30 years will occur in cities of developing countries not the first world. In fact the Western elite that can afford to experiment with vertical farming are undergoing falling birth rates, not population growth.
The problem with vertical farming, as with the Green Revolution, is that both are created by the developed world, for the developed world. Despite their ‘feeding the world’ rhetoric, the reality is difficult to ignore. It comes as no surprise that vertical farming is being hailed as the third Green Revolution. While yield and output have increased, food insecurity persists.
The task of feeding an exponentially growing population with finite resources is perhaps the most pressing and dreaded issue of our time. We need integrative and regenerative agricultural practices that work with already naturally existing ecosystems and communities, contrary to the one size fits all agriculture practiced in America today. Given our many failed attempts at feeding the world, we need to try different approaches that are global by definition; technologies that consider how the different individual localities interact with each other as a dynamic whole. Technologies that facilitate this systemic behavior encourage empowerment and resilience, traits that result in productivity, stability, sustainability, and equitability by default.
Advancements in renewable energy and vertical farming combined with other production methods could one day be sustainable for populations in the developed world, or for some, Mars. As for the farmer of a 1 acre farm in India, those solutions are not applicable or realistic at the present moment. Food and ag-tech need to be accessible to everyone right now, not just the salad bar elite of the future.