Vertical farms and future cities

Sustainability a big theme at the World Science Festival

Posted by Maywa Montenegro (Guest Contributor) at 10:01 AM on 02 Jun 2008

What do vertical farms, green roofs, soft cars, breathing walls, and Dongtan, China, have in common? They were all subjects of discussion at Friday's Future Cities event in New York City, part of the four-day 2008 World Science Festival.

To a packed house, Columbia University microbiologist Dickson Despommier described his vision for feeding the planet's burgeoning, and increasingly urban, population. The vertical farm takes agriculture and stacks it into the tiers of a modern skyscraper. Instead of stopping at the corner pizzeria for dinner, Despommier suggested, you could pluck a nice head of lettuce, maybe some corn, and some tomatoes for a big salad, all in your own building, on the way to your apartment. You can't get fresher or more local than that.

According to Despommier, the farms will be "grown organically: no herbicides, pesticides, or fertilizers." (Of course, being indoor, there won't be many insects to spray for.) The farms will also require much less irrigation since all water can be re-circulated, and they'll curb the growing pressure to turn forest into farmland.

The vertical farm sounds (and looks) pretty amazing, and certainly Despommier deserves much credit for thinking boldly ... but I was left with several questions.

How, for instance, do the crops on a completely bug-free indoor farm get pollinated? Would this system only work for a few fruits and vegetables, or also grains? (It's one thing to imagine urbanites planting some veggies on a veranda, but very much another to contemplate how this would work with things like wheat, rice, sugar, and corn.) The much larger question, of course, is yield. How many of these high-rise farms would it take to put even a minor dent in global food consumption?

That said, I enjoyed Despommier's spirited talk enormously.

Here's a short list of the other participants in last night's panel, if you'd like to read more about them:

• Blaine Brownell is an architect with expertise in how revolutionary eco-materials have the potential to facilitate sustainable building and design. He is a visiting professor in sustainability at the University of Michigan as well as founder and director of the design/materials research firm Transstudio.

• Majora Carter is a leading environmentalist whose rallying cry is "Green the Ghetto." A 2005 MacArthur fellow, she is the founder of Sustainable South Bronx, a community-based organization that is spearheading efforts to revitalize disadvantaged neighborhoods in New York City and beyond.

• Dickson Despommier is a pioneering researcher in the development of urban vertical farm skyscrapers for food production. He is a professor of public health and microbiology in environmental health sciences at Columbia University's Mailman School of Public Health.

• Peter Head is an expert on the sustainable development of cities and the project leader for China's first eco-city, Dongtan. An award-winning structural engineer, he is the director of Global Planning at Arup, the worldwide engineering, design, and consulting firm. Head was recently named one of "50 global green heroes who could save the planet" by The Guardian.

• Walter Isaacson is the president and CEO of the Aspen Institute. He has been the chair and CEO of CNN and the editor of Time magazine. He is the author of Einstein: His Life and Universe, as well as biographies of Benjamin Franklin and Henry Kissinger.

• Mitchell Joachim is an architect and urban designer as well as a partner in Terreform, a New York-based organization for philanthropic architecture and ecological design. His design of a compact, stackable "city car," developed with the MIT Smart Cities Group, was a 2007 Time Magazine Invention of the Year.

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17 Comments | Post a Comment

Sunlight in Vertical Farms

I wonder if he's ever tried growing vegetables inside the house? If I recall my physics, the intensity of the sunlight coming through the window diminishes as the square of the distance. (John Phipps has also identified this minor problem in the plan.)

by bharshaw at 11:53 AM on 02 Jun 2008

application of vertical farms

All other things being equal, vertical farms, like greenhouses, are going to have a higher capital and operating costs and energy consumption, and thus more ecological impact, than traditional farming. Even if it is possible to avoid the use of artificial lighting, ventilation will be a major energy consumer in these systems. It is unlikely that the reduction in physical footprint due to stacking would by itself be enough to offset the increased economic and environmental costs.

However, farms of this sort represent a major opportunity to integrate food production with human habitat, provide fresh local food, and reduce shipping and processing costs/impacts. So I think that it will make sense to implement systems like this for high-value, high-density, perishable and sensitive crops. So I could see salad, berries, herbs, and some annual vegetables being grown in this context. The savings due to water efficiency, reduced pest problems, and reduced shipping costs and losses may well justify the investment. Particularly once people recognize that living next to your food can be a very pleasant experience.

Conversely, it is very unlikely that it would ever make sense to grow grains this way: grains require a lot of space and a lot of sun, and are easy to ship long distances at relatively low energy cost (compare the impact of a rail car full of wheat to that of a refrigerated truck full of salad).

by GreenEngineer at 12:10 PM on 02 Jun 2008

Don't Hate; Pollinate

Q: How, for instance, do the crops on a completely bug-free indoor farm get pollinated?

A: Apiaries.

Nobody ever said it would be bug-free; only a drastic reduction of pests. Apiaries inside would solve the pollination problem.

by cavecanem at 1:29 PM on 02 Jun 2008

Verticle farms and net energy

As I understand it growing plants indoors take 30-50 watts per square feet an average of ten to twelve hours per day just for lighting. (You can get away with less lighting, but have less productivity as well.)

If we are really going to run the world on renewable energy then we should consider that a solar or wind farm or even roof photovoltaics don't produce that amount of energy on average over the course of a year. In short, a one story indoor greenhouse that was not built of a transparent material could not produce enough electricity to from its roof to drive its lighting needs.

Or to put it another way, an outdoor farm has a lower land use footprint than a vertical farm and the solar cells, CSP or wind generators needed to light it.

If you want to advantage of indoor farming, dome the farm over to make it into a giant one story greenhouse. Add raised or sunken beds if you wish. You can make direct use of the sun for lighting like any normal farm or greenhouse. And you can use passive solar to heat and cool it too. Doing all this can quadruple production compared to an outdoor farm and greatly increase water efficiency too. At the moment I'm guessing it is not worth the capital investment, which would be considerable. Given the changes we've already locked in, and the further changes we are likely to lock in while we dither, putting some of these in place might be good insurance, a good investment in food security.

by Gar Lipow at 2:00 PM on 02 Jun 2008

Con-vexing

A large building with a convex curve with said curve facing south with the best light-allowing glass would work wonderfully. The north side of the building can be used to store rain barrels for water. With ample natural light, a wind turbine or two on the building should suffice.

Fiber optics could also channel sunlight, as well.

by cavecanem at 2:14 PM on 02 Jun 2008

Convex

One way or another you are still using up the same land at the very least as a one story farm. Either your convex building is one story, or it shades land equivalent to what an outdoor farm or one story greenhouse would require. The point being that a multi-story vertical farm has no real advantage over a one story greenhouse. Unless plants and PV use different wavelengths? Can you use optical splitting to separate out the wavelengths PV or CSP need and grow plants and generate electricity on the same land, and get say 90% of the electricity you would get if you were not doing optical splitting and 90% of the plant growth if you were not doing optical splitting? Any one have a source on this, wavelengths for PV, CSP, and plants?

by Gar Lipow at 2:27 PM on 02 Jun 2008

Elephant In Living Room

This laughable idea is just another in the many attempts to deal with constant population growth and overpopulation by doing anything but dealing with those problems directly. Aside from serious questions about whether this can actually work, there are the issues of how much energy a vertical farm would consume and the level of nutrition/taste would be provided by its plants.

by Wolverine at 3:08 PM on 02 Jun 2008

Lighting

I have seen proposals for vertical farms that use artificial light. They are absurd, of course. The farm is going to have to be able to do its thing with natural light, or the energy costs won't balance out.

That said, I think there are ways to get a favorable footprint reduction out of something like this. Don't think of it as a "farm". Think of it as a building (probably residential, but possibly commercial) with integrated gardens. The point is not to produce lots and lots of food, but to produce some food very close to point of use.

There are ways you can bring light into a building (Skylights and light shelves; fiberoptics, not so much) so that a multi-story arrangement can be utilized effectively. You'll never get the full-on sun exposure that you get with an open-field planting, but not everything wants that. Salad greens and some herbs, notably, like indirect sun or a limited amount of direct sun, especially in the summer when the sun is strong. In the winter, the sun is lower in the sky, and harvesting sun into a multi-story system becomes much easier.

The biggest challenge, frankly, will be to get people to change how they think of buildings and their relationship to them, and getting them to accept the required level of management to keep a system like this humming along. It wouldn't have to be terribly labor-intensive, but it would require some attention on an ongoing basis. And attention is something that everyone seems to be short of.

by GreenEngineer at 12:33 AM on 03 Jun 2008

There's a reason

that indoor house plants are mostly limited to non-flowering, non-fruiting, non-edible decorative greenery. Many reasons in fact.

It's hard to imagine a city building designed to accommodate a substantial quantity of food production that does not severely compromise its other functions. Even farmers don't generally wish to live in their greenhouses. Marginal production of a few herbs and salad items yes. Meaningful quantities of staple foodstuffs for the city dweller, sufficient to justify the resources of energy, space and capital required for its production: I don't think so. When I was in architecture school in the 1980's student urban design projects were full of flying cars and hoverbikes. This looks familiar.

The true meaning of life is to plant trees, under whose shade you do not expect to sit.

by spaceshaper at 4:33 AM on 03 Jun 2008

However

I do fully support the concept of urban farming - between buildings, around buildings, on top of buildings. Just not in buildings. I've read that Paris in the latter part of the nineteenth century was able to produce all its milk, eggs and fresh vegetables within the city limits. No vertical farms were involved that I know of.

The true meaning of life is to plant trees, under whose shade you do not expect to sit.

by spaceshaper at 4:54 AM on 03 Jun 2008

poo-poo the poo-poo-ers!

Nothing is perfect, needless to say. But that does not at all mean, that promising new ideas should not be tried out.

SpaceShaper should conduct a European tour, of a group consisting at least in part of GreenEngineer, Gar Lipow, Wolverine, CaveCanem, and AmazingDrX.

Ideally, Tom Philpott should be along, to give a foody angle. But no doubt he is busy, doing whatever with his arugula, and/or his pigs.

Chickens deserve our true friendship! So do fish! So do other sentient beings! Let us learn to be kind.

by caniscandida at 5:40 AM on 03 Jun 2008

Wow

I thought about this for awhile, skyscraper farming. I have envisioned malls and large building being retrofitted with solar greenhouses on their south facing walls and roofs.

But imagine whole skyscrapers? But how do you get the light to do this without burning (with coal fired power plants, literally) electric power?

The solar power falling on the building surface is signifigant, but not enough to grow plants on the shady side of a vertical greenhouse/farm.

The solar energy can be magnified with mirrors, the same way it is done in solar furnace applications, but only to around 2 or 3 suns concentration, enough to enhance the light inside the greenhouse structure, but not enough to overheat everything.

The mirrors could be mounted wherever buildings or cars need to be kept cooled from the solar heating effect. Heat deffered (and air conditioning load) and solar wall greenhouse growing and energy harvest enhanced.

With smart control systems the optimum amount of light could get to a solar green power tower skyscraper all day long. Solar PV/heat cogeneration inside the greenhouse and wind turbines in the chimney effect flow of the greenhouse ventilation system would collect a huge amount of energy, enough to more than power the building.

Retrofit those skyscrapers now! Urban farms and farmer's markets could spread all the way up the towers, on the sunny sides. Yes every side could be the sunny side with solar mirrors.

A green, growing beanstalk structure greening the urban skyline. It's possible.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

by amazingdrx at 5:40 AM on 03 Jun 2008

Core

The core of the building remaining as offices, businesses, and residential space, of course. With the greenhouse wall anywhere from 6 feet (just enough for gardeners to access, residents even with their very own urban gardens) to 20 feet or more.

Built back into the floor level for green office spaces or farmer's market/grocery stores.

Louvre solar PV/ heat cogeneration collectors mounted as buffers could collect solar energy and regulate the amount of light/heat passed through to the inner areas of the building.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

by amazingdrx at 5:57 AM on 03 Jun 2008

Vertical does not mean inside...

...vertical simply means stacked.

A series of open or nearly-open floors stacked on top of each other, often at various angles or floor heights or with increasing setbacks as the structure goes higher in order to maximize sunlight.

Also, some might use hydroponics as a way to maximize production.

It's not really a "building" so much as it would be a giant, open, tapered shelf.

Little to no glass or walls or unnatural ventilation required.

by Tasermons Partner at 10:44 AM on 03 Jun 2008

Colbert

Just had this guy on. Pretty good segment, should be on video soon.

I think he's like the mirror idea and the greenhouse shell too.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

by amazingdrx at 8:59 PM on 12 Jun 2008

Fiber optics

Yeah, you can bring light into a building. About a 150 square foot concentrator can light around 1000 square feet for human use. But that is a long way from the VF concept. Ok lettuces, but really most farm footprint is grains and legumes and animal. Fruits and non-starchy veggies are a tiny percent of the farm footprint. And I think growing those things in the city is great. But it has nothing to do with the VF concept. I did think that maybe you could do the same thing you do with buildings - do a combined CSP with greenhouses. Use parabolic concentrators, use half the energy to grow plants, half the energy to generate solar thermal electricity, use waste heat to desalinate waste water. But you that ends up with a greenhouse about five times the cost of a conventional greenhouse, and a CSP generator that generates about half the electricity you would have if you were not splitting the light. So it seems like we are better off with greenhouses that don't generate electricity (maybe the kind that desalinate water as a side effect) separate from solar electric generators. A greenhouse that grows food and desalinates its own water, and a CSP system for generating electricity will be less expensive as seperate facilities than integrated.

I still like the idea of a combined greenhouse solar electricity facility in principle. Using fiber optics to seperate light into two functions gives you essentially zero net footprint electricity. You generate more food per acre than an outdoor farm, accept polluted water as yoru water input and purify it for farm use, and get electricity beside. But your capital costs are huge - far worse than conventional renewables or food production, a sort of anti-synergy.

by Gar Lipow at 11:36 PM on 12 Jun 2008

Retrofit

I think retrofit of large buildings would be more practical Gar. Greenhouse space behind those huge glass tower surfaces. Using mirrors to optimize light on the building surfaces.

Fiber optics would be too expensive and reduce the light intensity too much to make growing crops practical. It is better to use interior space as expensive real estate, as it is now.

http://amazngdrx.blogharbor.com/blog John Schneider, Northern Wisconsin

by amazingdrx at 11:57 PM on 12 Jun 2008

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