A New Wave of Agriculture: Vertical Farms 101
Agriculture joins economic pillars like infrastructure, waste management and energy production as one of the most important issues we need to address in order to take meaningful steps towards a sustainable culture. America is a series of broken systems. Though technically still a theoretical construct, Vertical Farms offer a new approach to our agricultural production with the potential to drastically change its effect on the environment. Not only are these visions interconnected, functioning ecosystems of their own, but they interface in numerous ways with the greater system of the city creating positive repercussions. One day in the not too distant future, Vertical Farms could be self-sustaining entities that exist as the epitome of efficiency for water, heat, power and waste.
The board stroke of a vertical farm is close to what it sounds like—stacked farming acreage in the middle of urban centers that allow for local food production in a closed environment while removing many of the negative effects that our current agro-industrial model levels on the environment and our food. A fair question is: Is this really important? I have written before on why we need to be promoting agricultural change in this country. Even still, why not farm on flat land in the middle of the country instead of in the middle of our cities? People can have an inclination to think that farming is inherently sustainable given its connection to the soil. After all, we're just growing plants, right?
In Dickson Despommier's new book on vertical farms, he points out that in fact agriculture is one the largest chemically polluting industries in the country, largely due to the amount of fertilizers, pesticides and herbicides. According to biologist and writer Janine Benyus, "since 1945, pesticide use has risen 3,300 percent, but overall crop loss to pests has not gone down. In fact despite our pounding the United States with 2.2 billion pounds of pesticides every year, crop losses have increased 20 percent." These chemicals ultimately get swept away in stormwater runoff to end up in our rivers, aquifers and eventually the Gulf of Mexico. From there the problems spread throughout food chains as oxygen levels in the waters drop and poisonous chemicals taint life at all levels (some making their way back to our kitchen tables).
Finding new food solutions for cities becomes more important everyday. As urbanization speeds up in developed countries, some estimates peg urban residents will comprise 70% of the world's population by 2050. Up until now, cities have garnered a reputation for being centers of consumption. While their inherent density makes them deft at producing jobs and tax revenue, a bountiful supplier of resources they are not. But perhaps they can be. Vertical farms would finally allow us to question the preconception that resources are produced in rural America to be consumed in urban centers.
Instead of trying (and failing) to encapsulate his entire book into this one article, instead I am going to focus more on the construct of vertical farms and their connection to the city. As for why our current farming model is "broken" I will simply paraphrase that we have a system built on the backs of petroleum products that creates a cyclical process of giving less nutrients back to the earth and thus requiring more chemicals. 31% of our nation's water use is for irrigation, most of it being flood-irrigation for farming. Even after we plant, grow and harvest crops on land that is prey to insects, drought, flood and disease, the process of harvesting and shipping produce is only further based oil consumption. Vertical farms address all of these issues. For a copious amount of case studies and examples, I recommend Prof. Despommier's book "The Vertical Farm" or the fantastic documentary "Food Inc."
For those of us that look ahead to a goal of a zero waste economy, the vertical farm is an amazing fixture in the technological landscape. If designed properly, the vertical farm should have no material waste. All plant waste from growing can be collected and dried on site while excess food clippings can be composted in basement space. The former can be burned as biomass while the latter can be stored in an anaerobic chamber to create methane gas byproduct. Both can be used to create power for the building while the excess heat can be used to heat the building in the environments that require it. The leftovers can be incorporated into nutrients for the next generation of crops. Its use of water is very similar.
While flood irrigation is a markedly inefficient use of water, vertical farms can come strikingly close to operating on a completely closed loop of water supply. Built on both hydroponics (growing of plants in nutrient-rich water) and aeroponics (growing plants in air with misting nutrient water on the roots) vertical farming can drastically cut the amount of potable water we need to devote towards growing food. These new methods of growing are like the CFLs and LEDs of agriculture. Reportedly, hydroponics can use 75% less water than surface irrigation and aeroponics can use 75% less than that. As one can imagine, given the system is closed, all of the water that is used can be collected either through drainage or through the transpiration in the air via dehumidification. Add a well designed rainwater catchment strategy and a vertical farm could pull relatively little water from municipal infrastructure and produce zero stormwater runoff.
I will admit that when I started hearing more about vertical farming, one of my first questions was how much food can you actually grow in a glass skyscraper and could stacked floor plates really be as efficient as open farmland? The answer seems counter-intuitive but positively surprising. It turns out that using different methods of stacking and hanging plants combined with new Organic Light Emitting Diode (OLED) technology, there are numerous types of produce that you can grow more of in a vertical farm than on the same acreage of the open range. In testing, some of the top performers are strawberries, radishes, tomatoes, lettuce.
The food production system is only the base of a model has many other components that can be incorporated as part of the larger ecosystem. The growing industry of fish farming can be employed on deeper parts of the floor plates, tied into water systems and producing a different, local cash crop. A tall building with great exposure can integrate renewable power production from photovoltaics or small scale wind turbines that could further lower the net cost of operation for the facility. This kind of versatility means that urban farms can respond to local demand and cater to the tastes of each city.
Agriculture is another example of us attempting to steer nature in the direction that best suits us while still ultimately controlling very little. All of the genetic modification in the world has succeeded in diverting heavy rains, droughts, locusts or disease. Each time crops are lost to events far outside our control, we lose time, money and energy used in every part of the process from transporting seeds and tilling the soil—and that's in addition to the food itself. For smaller farmers, they really do "bet the farm" on their crops each year.
Enter vertical farms, where all of these variables can all be carefully controlled in an indoor environment. In fact growing seasons would be a thing of the past all together. We already have many functioning, profitable greenhouse examples to prove that proper care can make these indoor farms producing food year round. Not to mention, once the food is produced it across the street from its buyers. All it takes to remove shipping entirely from the supply chain is to put a retail store in the bottom floor and let consumers come and buy food themselves. I had commented previously on a theoretical model for supermarket growing called Agropolis.
At this point we have a construct that farm can function as an impressive, closed system with an outflow of products into a city, but it also has opportunities to open the spigot in the opposite direction to create inflows of urban waste streams and activity. Processing facilities at a vertical farm could be sized not only for their own food waste, but the food waste of surrounding blocks. Some estimate that 33% of our municipal waste could easily be diverted to composting facilities that could ultimately be producing power through anaerobic digestion and as well as a base for organic fertilizers. Stormwater from adjacent properties could be taken into cisterns in the lower levels to reduce the amount of runoff that tax local sewage conveyance systems. While having a local, energy efficient, organic food source has many benefits of its own, a system that can serve as a sink for urban waste that reduces the ecological footprint of the city at large would be truly impressive.
Too good to be true? By now a reader could think that the list of accolades is long for something that still hasn't been built yet. Unsurprisingly, the reason comes down to money. The bottom line is that no one knows the bottom line to construct one of these ecological towers. Like any significant architectural project, there is a critical mass of design energy from architects and engineers needed to create something that is real enough for it to be confidently priced. There are models that exist that forecast profitability for vertical farms, but without accurate ideas of how much upfront capital is required such a forecast is hazy at best. Up to this point, most of the final products of explorations into vertical farms have been zippy looking renderings. Don't get me wrong, they do look alluring, but there is a level of technical feasibility that someone needs to invest in order to achieve an underlying level of realism for such a project. As of yet, no one has been willing to fund such an effort.
Prof. Despommier argues that we should divert billions federal money into a first round of prototype farms across the country. I am not going to go quite that far, but I do think we should build one. There is an overwhelming amount of data to be gathered from just having one, functioning example to justify its construction. Personally, I think this could have more immediate benefits to humanity than landing on Mars or setting up a Moon base (in fact, we may need some next generation farming technology if such sci-fi goals are to be eventually realized).