Can Urban Agriculture Feed a Hungry World?
Agricultural researchers believe that building indoor farms in the middle of cities could help solve the world’s hunger problem. Experts say that vertical farming could feed up to 10 billion people and make agriculture independent of the weather and the need for land. There’s only one snag: The urban farms need huge amounts of energy
By Fabian Kretschmer and Malte E. Kollenberg
Aug. 17, 2012
With its many empty high-rise buildings, Manhattan was the perfect location to develop the idea. Despommier’s students calculated that a single 30-story vertical farm could feed some 50,000 people. And, theoretically, 160 of these structures could provide all of New York with food year-round, without being at the mercy of cold snaps and dry spells.
The Power Problem. Despite these promising calculations, such high-rise farms still only exist as small-scale models. Critics don’t expect this to change anytime soon. Agricultural researcher Stan Cox of the Kansas-based Land Institute sees vertical farming as more of a project for dreamy young architecture students than a practical solution to potential shortages in the global food supply.
The main problem is light — in particular, the fact that sunlight has to be replaced by LEDs. According to Cox’s calculations, if you wanted to replace all of the wheat cultivation in the US for an entire year using vertical farming, you would need eight times the amount of electricity generated by all the power plants in the US over a single year — and that’s just for powering the lighting.
It gets even more difficult if you intend to rely exclusively on renewable energies to supply this power, as Despommier hopes to do. At the moment, renewable energy sources only generate about 2 percent of all power in the US. Accordingly, the sector would have to be expanded 400-fold to create enough energy to illuminate indoor wheat crops for an entire year. Despommier seems to have fallen in love with an idea, Cox says, without considering the difficulties of its actual implementation.