Preface. Vertical farms sound even more impossible than rooftop farms, which at least can use free sunshine. And they use massive amounts of energy to heat, cool, ventilate, light, and so on, not a good direction to go given energy decline beginning in the near future.
Alice Friedemann www.energyskeptic.com author of “When Trucks Stop Running: Energy and the Future of Transportation”, 2015, Springer and “Crunch! Whole Grain Artisan Chips and Crackers”. Podcasts: Derrick Jensen, Practical Prepping, KunstlerCast 253, KunstlerCast278, Peak Prosperity , XX2 report
I have a vegetable garden, and after pressing seeds into the soil, with almost no effort I can come back and harvest whatever I planted six weeks later. All of this bounty came from free soil, free sunshine, and free rain, though we do use drip irrigation half the year.
Your proposal of a vertical farm is a laudable goal for increasing food security, helping to feed the 3 billion more people expected by 2050, and reducing the energy and emissions caused by the production and transportation of food long distances.
From what I could find in commercial real estate listings, that’ll set you back about $10 million dollars.
Or you can lease space for $22 to $40 per square foot, at $22 to $40,000 a month for 10,000 square feet in New York city, or better yet lease in the Bronx or Queens where prices are lower (Goodman 2019).
New York City has 193,689 acres, but just a few are indoors or in shipping containers. At best New York could support 1,864 acres of such farms, nearly all of them rooftop (Goodman 2019). But 162,000 to 232,000 acres required to provide residents the 40,760,000,000 pounds of fruits and vegetables they consume every year.
So you found a place. The first thing you’ve got to do is buy lots of lights. Outdoors, all the leaves of a plant need to be directly illuminated by the sun to activate photosynthesis. But indoors, even in a glass-walled room, there’s not enough light. So you’ll need huge amounts of artificial lighting to match what the sun delivers, about 100 times the lighting seen in a typical office building (SA 2019).
And you’ll need a lot of electricity to light all these bulbs. Crops like potatoes or tomatoes need about 1,200 kilowatt hours of electricity for every kilogram (2.2 pounds) of edible fruit produced. If half of America’s vegetable crops were to be grown in vertical farms, just the lighting alone would require over half of all the electricity generated in the U.S. (Cox 2016).
Mills (2012) used the low estimates of how much Cannabis is grown indoors in the U.S. and deduced this consumes about 1% of U.S. electricity (3% of California’s electricity) at a cost of $6 billion a year. That’s equal to the energy used by about 2 million homes. But then they can afford to do so, marijuana commands a price of about $210 to $320 (Statista.com 2018) per ounce whereas fresh vegetables are just pennies per ounce.
You’ll need to pump water up to all the floors. I can’t say how much energy or what it will cost, but water is heavy. The state of California uses a tremendous amount of energy to move water around — 19% of California’s electricity, 30% of its natural gas, and 88 billion gallons of diesel fuel every year, and this demand is growing (Klein 2005).
And that’s just the start, you’ll need haul acres of dirt and fertilizer to every floor, buy shelving to put the plants on, purchase nutrient monitoring systems, machinery to harvest plants, heating and cooling systems, ventilation, shading, dehumidifiers, fans, computers, and vans to truck your produce to markets.
There’s only a limited range of crops that can be grown. It only makes sense to grow leafy greens or herbs since most of the plant can be eaten. Other crops have too many inedible leaves, stems, and roots.
You’re not exactly going to be feeding the neighborhood either. A cup of butterhead lettuce weights 55 grams (2 ounces) and contains 7.2 calories, so customers will need to eat 280 cups of greens weighing 15,400 grams (34 pounds) to get their daily required 2,000 calories (SelfND 2018).
If you don’t find any of this daunting and go ahead with the project, congratulations, you’ll be the only vertical skyscraper farm in the U.S. and the rest of the world, except for Japan (Takada 2018). It will be interesting to see if Japanese, and a new vertical farm being built in Dubai, enterprises can compete with farms on the ground in cities or near them, and nearby massive greenhouse operations that can use natural sunshine.
Cox, S. 2016. Why growing vegetables in high-rises is wrong on so many levels. Alternet.org
Goodman, W., et al. 2019. Will the Urban Agricultural Revolution Be Vertical and Soilless? A Case Study of Controlled Environment Agriculture in New York City. Land Use Policy 82.
Klein, G., et al. 2005. California’s water-energy relationship. California Energy Commission.
Mills, E. 2012. The carbon footprint of indoor Cannabis production. Energy Policy 46: 58-67.
SA. 2019. Growing up: skyscraper farms seen as a way to produce food locally–and cut greenhouse emissions. Scientific American.
SelfND. 2018. Lettuce, butterhead (includes boston and bibb types) raw nutrition facts & calories. Nutritiondata.self.com
Takada, A. 2018. As high-rise farms go global, Japan’s Spread leads the way. Japantimes.