Farmers In The Sky
It's not some science-fiction scenario. It just might be the future of farming, and it's coming to a city near you.
Imagine it. Clusters of high rises, 30 stories tall, dotting the urban skyline, filled not with offices or apartments but with hydroponic farms that produce enough food to sustain the teeming throng of city dwellers below and provide them clean water as well.
Pie in the sky, you say?
No, zucchini in the sky, replies Dickson Despommier, a leading advocate of vertical farms. And tomatoes and strawberries, vegetables and herbs and a wealth of other foods growing hydroponically high above crowded city streets, enough food to fill the needs of a teeming urban population.
And there's more – much more – in this vision. These vertical-farm skyscrapers that Despommier and others see someday filling the urban landscape would also lower America's dependence on petroleum, help combat global warming, generate their own energy and drastically reduce the waste water and trash spewing out of our cities and into the environment.
Oh, and produce a healthy return for the investors who build them.
Dickson Despommier is a professor of Public Health in Environmental Health Sciences at Columbia University. Nine years ago he had a class working on the question of how to green New York, bringing food production into the city. They considered the benefits of rooftop farming, but obstacles kept cropping up, Finally, Despommier said to them, "Why don't we just move the whole thing indoors?"
Why not indeed?
The classroom discussion grew into a Web site, www.verticalfarm.com, a consulting firm, and a movement. Despommier has become a leading advocate for a complete restructuring of how the world produces its food.
But he's not a voice crying out in the wilderness, he said. Far from it. The idea has caught on and the world is listening. Last fall he travelled to China for a conference, and in March he was in Dubai, where the idea is picking up steam. Imagine if that desert nation could begin producing its own food, even exporting it. "It could change the whole dynamic of the Middle East," he said.
MSNBC, New York Magazine, CNN, the BBC, the Times of London, Popular Science and many more media outlets have carried stories on the plans.
It's an idea whose time has come, according to Chris Jacobs of United Futures. With Despommier, Jacobs has been planting the seeds of the revolutionary idea. Now those seeds are beginning to take root.
Jacobs said it's much too early to make an announcement, but he has been pulling together a working group of city planners, lawmakers, architects, engineers and – maybe most importantly – funding people, to see if a vertical farm can be built in one of the U.S.'s major cities. He can't say which one yet and they haven't come up with a hard plan yet, but the meetings are real and the interest is growing.
Like Despommier and Jacobs, Glen Kertz – CEO of Valcent Products Inc. – sees traditional, soil-based corporate agriculture as a dead end. Transporting food products hundreds, even thousands, of miles uses fossil fuels and results in a product that's not as fresh or as healthful as locally grown produce.
"When the average American sits down to eat a meal, some component of that meal has travelled at least 1,500 miles," Kertz said. "From an energy standpoint we're killing ourselves. And a lot of our food comes from a lot farther, from Chile, from Israel."
So what is a vertical farm?
The idea is fairly simple, although the devil is in the details. Despommier and his students have put together a proposal based on hydroponically growing a 2,000-calorie-a-day diet for 50,000 people. Each building would be 30-stories tall with a footprint of a city block. There would be offices and labs on the ground floor and acres and acres of hydroponic gardens above them. Basically, if it's sold in the produce section of your local supermarket, it can be grown in a vertical farm, Despommier said.
Growing the food near the urban population that's going to consume it could eliminate the fleets of trucks which now carry produce from farm to city. This would slash the transportation cost that's part of the price of everything you buy and reduce or eliminate the need for the petroleum fuels that feed those trucks, along with the clouds of greenhouse gases they produce.
Ideally, the facility would take in treated waste water cities nowdump and run it into the vertical farm. Under Despommier's proposal, gray water – city waste water that has been filtered and is clean enough to put back into the environment but is not fit for human consumption – would nourish the plants and be recovered through evapo-transpiration. By the time it had passed through the system, the water could be usable as potable drinking water for a thirsty population.
The vertical farms could be topped by arrays of solar panels or wind turbines for power, augmented by the conversion of waste biological product – stems, branches, vines and weeds – into energy.
None of these are wildly new or futuristic technologies. Hydroponic growing has been around since Babylon's hanging gardens, and in El Paso, Valcent is already growing produce in a high-density vertical growth system. The only thing really new about all this is the idea of putting it all together in a high-rise urban setting.
Moving food production from the country to the city would also relieve the pressure for more farm land. The world's population is growing and more farm land is needed to feed all those people. At the same time, a healthy percentage of our current farm land is becoming less able to produce crops due to build up of salts in the soil from chemical fertilizers.
The World Health Organization has estimated that by the year 2050 mankind will need to find another billion hectares of arable farm land to provide food for a population expected to grow by some three billion people. That's an area 20 percent larger than Brazil. There just isn't that much arable land available. If the human race is going to avoid mass starvation, an alternative has to be found.
Enter Vertical farms
When people moved to the cities, Kertz said, the cities had to grow to accomodate them. Partly that was by gobbling up adjacent farm land as the urban centers spread out. But cities also have grown by going up. Now it's time for farming to follow that lead and go up as well he said.
Growing in soil limits the grower to the number of plants that can be put in a finite, two-dimensional area before causing stress that reduces yield or even kills the plants.
The advantage to going vertical, according to the Valcent CEO, is that the sky is literally the limit. Early trials of the Valcent HDV system indicate it gets as much as 20 times the amount of vegetables per acre compared to soil production, while using only a fifth of the water required by field crops. And the production is year-round rather than limited by the season.
"In a typical soil-based farm you could get about 350,000 to 450,000 heads of lettuce a year from an acre of land, depending on factors like the variety and the weather. Take the same acre of land and plug in one of these (the Valcent high-density vertical growing system) and you'd get about four million heads of lettuce a year."
Numbers like that suddenly snap your head around, and they certainly get the attention of the people who might have money to invest in such a production system. And yield isn'tthe only area where high-rise hydroponics has the edge.
Other advantages
On their Web site, Despommier and his students have outlined a list of other potential benefits to vertical farming. These include:
• Virtually no crop failures due to droughts, floods, pests, etc. It would require a huge natural disaster, on the scale of an earthquake or tornado, to disrupt growing.
• Food in vertical farms would be grown organically employing chemically defined diets specific to each plant and animal species. There would be no herbicides, pesticides, or fertilizers.
• Vertical farming would eliminate agricultural runoff, a major source of pollution.
• It would also allow farmland to be returned to the natural landscape, restoring ecosystem functions (e.g., increases biodiversity and carbon sequestering and air purification).
• Vertical farming would greatly reduce the incidence of many infectious diseases that are acquired at the agricultural interface by avoiding use of human feces as fertilizer for edible crops.
• The system would convert abandoned urban properties into food production centers and create new metropolitan employment opportunities.
• Vertical farming also could be used for the large-scale production of sugar (sucrose) to be used in a revolutionary new method for the production of non-polluting gasoline.
Kertz added that food grown in such a system would also be healthier for the consumer, and not just because it had been grown in a controlled environment without the need for pesticides, herbicides or chemical fertilizers.
"If a head of lettuce is cut in a field in the San Joaquim Valley, cut from its rootball, within 24 hours it's lost half of its nutritional value," Kertz said. "By the time it gets to you, which is several days, typically its lost 67 percent of its nutritional value. What you're chewing on is basically green cotton, green cellulose. It lost more than half its nutritional value and most of its flavor."
Lettuce grown in the Valcent HDV system can be harvested and shipped with its rootball intact so even if it has to travel any great distance, it retains more of its nutritional value. And because production is not tied to the land it might not have to be transported far at all.
"You pop down a little unit literally in the parking lot or on the roof of the local grocery store, it's being grown and delivered in the same place."
Is it feasible?
No one's going to build a massive, urban vertical farm if he doesn't think it will make money at the end of the day. Despommier's students have shown that it can.
Using current construction costs and technologies, they've estimated the cost of building the first vertical farm at approximately $83.7 million dollars. Their economic model assumes the first vertical farm would be geared to a single crop – lettuce – and would generate a net annual profit of roughly $12 million, based on current demand and prices. With those numbers (available on the verticalfarms.com Web site) they estimate investors in the first vertical farm would recoup their investment in seven years. After the payoff, investors would earn $12 million annually from operating profit through the tenth year of the facility's operation and $14 million per year thereafter. In other words, the principal investment of $84 million can be effectively doubled in less than fifteen years.
And that may be one more advantage of the concept; it will not require a lengthy or devisive debate about "the future of farming" or losing traditional ways and rural values. If it makes sense, if the benefits are as great as Despommier believes and if the economics are as good as his students have suggested, it will happen. People will build vertical farms because the world needs food and this will be the best means of producing it.
John Baur is editor of The Growing Edge.
