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Vertical farming is an energy nightmare. It requires at least 1000x more energy than conventional agriculture because you have to provide supplemental light for
by maliker 11y ago
Vertical farming is an energy nightmare. It requires at least 1000x more energy than conventional agriculture because you have to provide supplemental light for the plants to grow indoors.
Others have addressed this:
"... the light required to grow the 500 grammes of wheat that a loaf of bread contains would cost, at current prices, £9.82. (The current farm gate price for half a kilo of wheat is 6p.) That’s just lighting: no inputs, interest, rents, rates, or labour. Somehow this minor consideration – that plants need light to grow and that they aren’t going to get it except on the top storey – has been overlooked by the scheme’s supporters. I won’t bother to explain the environmental impacts."
-- http://www.monbiot.com/2010/08/16/towering-lunacy/ http://www.monbiot.com/2010/08/16/towering-lunacy/
- mu_killnine 11y agoThis is why you'll notice most existing vertical farms don't grow things like corn or soybeans. They grow microgreens. Organic-foodie pricing aside, I think it's largely because that's the only crop that really takes to this style of farming and can still make money. The aforementioned crops just need too much space and energy to work commercially.
- hanniabu 11y agoThat's true. Cross like corn and tomatoes already grow vertically so there's not as much that can be done about that as opposed to a leafy gran that is growing a foot or so in a 20ft room. It only makes sense to layer it there.
- mikepurvis 11y agoYou lose out on density, but I do wonder about putting these vertical units around the outside of office towers somehow? So you get many of the advantages of isolation, but you also benefit from free natural light? It seems insane to harvest solar energy just to pump it back into grow lamps. I would be fine with sitting at an office tower "window seat" that looked out through 5 feet of agricultural activity.
- zongitsrinzler 11y agoThis is a really interesting idea. I'm not sure if all the car gas might be a showstopper.
- hanniabu 11y agoThey're already doing this with offices and hotels. Just not commercially. It's more so for publicity for the companies that they're green.
- danielweber 11y agoThere is something to be said about esthetics. Cities make a point to keep open space, and pay a high price to do so, because open spaces are psychologically valuable for people who live in cities. NB: I'm still skeptical about urban farming, and too much urban farming completely destroys the "open space" aspect.
- hanniabu 11y agoI wish I had the link on hand but there was a study not to long ago that being surrounded by more plants dramatically increases well being and relieves stress. I wouldn't be surprised if it plays an equal or greater roll in mental health than spacial openess.
- giltleaf 11y agoNot to any study in particular, but this article links to a few others that make that case https://urbanverticalproject.wordpress.com/2015/07/21/vertical-succulent-gardens/ https://urbanverticalproject.wordpress.com/2015/07/21/vertic...
- bloat 11y agoIs it possible to pipe free sunlight into a vertical farm using fiber?
- maliker 11y agoYou would need a fiber collection area the same size as the total floor space of your vertical farm. So it would have to be absolutely massive.
- scott_karana 11y agoWell, if the intensity of light in your locale is double what you need, couldn't you diffuse it with a lens/prism system accordingly? Eg, if you're growing a mild-sunlight plant in high-sunlight climes like arizona, you could have a collection grid half the size of the delivery grid.
- e12e 11y agoSo, this sounds like it could be great for very arid areas, where it might be easy(?) to build a massive solar farm in the desert, and run a cable to the city -- but not sustainable to water the same area where one can put solar? Switch solar for wind turbines in areas with little sun light and strong winds. I wonder if it would be any easier to recycle water in a city/building than if used for "normal" farming?
- tagawa 11y agoI'm based at a university where there are a couple of solar-tracking devices feeding fibre optic cables to a corridor in a nearby building. The light from the 1 metre-wide trackers is laughable. You can see the light source but it's not strong enough to practically illuminate anything. Maybe this is an old installation and the technology has since improved, but my instinct is that solar panels powering batteries to light LEDs would be much more efficient.
- exelius 11y agoNo, but it is possible to convert that sunlight into solar energy and use that to power LEDs. More efficient too; since you can use LEDs that emit the proper spectrum for the plants you're growing.
- giltleaf 11y agoThough Monbiot is cited in the original article, he doesn't really understand vertical farming. Not only are energy costs plummeting (which he doesn't address), but not all vertical farms rely on artificial light. Click back into the article and check out Sky Greens.
- maliker 11y agoElectricity prices have been rising steadily for years. And this is before any serious attempts to reduce carbon emissions, which is expensive. Source: http://www.eia.gov/todayinenergy/detail.cfm?id=20372 http://www.eia.gov/todayinenergy/detail.cfm?id=20372 For vertical farms that only use natural light, they only collect light equal to the building surface area (actually it's a bit worse on the sides). So, it would work fine for just the top story of the building plus a few crops on the sides.
- deleted 11y ago[deleted]
- giltleaf 11y agoI definitely misspoke, my bad. I mean that the cost, in terms of energy requirement, required to produce light is going down. Source: http://www.eia.gov/todayinenergy/detail.cfm?id=15471 http://www.eia.gov/todayinenergy/detail.cfm?id=15471
- hanniabu 11y agoI used to work for a company with a very mechanical system similar to Sky Greens (City-Hydroponics) and the costs end up being transferred into maintenance. All those moving parts cause a lot of problems.
- giltleaf 11y agoThat is an interesting comment and something that doesn't often get brought up. Thanks for pointing that out.
- exelius 11y agoThis isn't as big a problem as you would think. It's actually theoretically possible for a combination of solar cells and LEDs to increase the amount of usable energy delivered to the plant: plants absorb light in the red and blue parts of the spectrum, and reflect green light. A solar cell can capture light energy across the entire spectrum and convert it to electricity, then the LED grow lights output an optimized spectrum. It's not possible today; but by converting green light to red through solar cells and LEDs, it will eventually be possible to deliver more light to the plants than they would have received from the sun. Also, vertical farming allows you to build a solar array somewhere sunny and transmit the electricity to an urban area. So rather than having a farm there, you would have a solar farm that transmits energy to a vertical farm in the city. Again; this is many years off, but vertical farming and solar power go hand-in-hand. What we build today doesn't make a lot of sense commercially, but as a species we absolutely need to invest in unprofitable vertical farming projects because in 100 years, they may be our only reliable way to farm food.
- maliker 11y agoI would like to see some math on this solar + LED combination. Solar PV is 16% efficient now. So the LEDs would have to put out light at least 6 times better than sunlight to break even. Not to mention the LEDs+PV cost money, whereas the sunlight is free.
- TTPrograms 11y ago"theoretically possible" You need higher efficiency solar, which is feasible with non PV techniques.
- maliker 11y agoSome of the latest PV is getting pretty good [1]. How much better is the light from LEDs than sunlight? [1] http://static1.1.sqspcdn.com/static/f/372352/22413458/1365584280200/efficiency_chart.jpg?token=YmjjAMNcgNjZQIEiq81a78mVnFE%3D http://static1.1.sqspcdn.com/static/f/372352/22413458/136558...
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- hanniabu 11y agoThere's a lot less energy going into transporting the food though and much less water is used too.
- maliker 11y agoTransportation of food doesn't take much energy. A UK national study found only 12% of the energy cost for all food production is needed for transportation [1]. Water conservation could be a benefit. But why not use the same techniques on flat ground instead of in a building? [1] (couldn't get the original source but it's referenced in https://en.wikipedia.org/wiki/Food_miles#Energy_used_in_production_as_well_as_transport https://en.wikipedia.org/wiki/Food_miles#Energy_used_in_prod...)
- hanniabu 11y agoGrowing in a building allows you to control the environment to grow year round and you can keep the plants quarantined from the outside world to minimize contamination from insects which eliminates the need for pesticides.
- maliker 11y agoI agree, pesticide/herbicide use could probably be near zero in a vertical farm.
- JoeAltmaier 11y agoBut...you have to have a climate-controlled building. If you already have one, and have extra space, then ok. But there's no way you can build a roof over the entire state of Iowa for instance. Very much a niche hobby for people in the city.
- primroot 11y agoThe only vertical farming I see as part of a sustainable future is Agroforestry. As for the rest of vertical farming, their wastefulness becomes even more evident once one considers that the nutritional profile of its production is often comparable (or even inferior) to that of weeds. For an alternative framework (rather than an alternative technique) take a look at Agroecology http://www.srfood.org/en/report-agroecology-and-the-right-to-food?fb_locale=pt_BR http://www.srfood.org/en/report-agroecology-and-the-right-to...
- giltleaf 11y agoI share your enthusiasm but see vertical farming as part of a new urban agroecology to incorporate into buildings rather than taking up acreage by themselves. I think the technology is being developed for mixed use buildings.
- fweespeech 11y agoThis is why there were a number of glass towers in the article. Indoor farming is really farming in a greenhouse with multiple levels of plants inside for most plants, only a few are actually grown with artificial lights.
- maliker 11y agoLight requirements for crops are proportional to the volume of the vertical farm. Light input is proportional to the surface area (actually a little). So vertical farm light requirements are much bigger than the amount of light hitting the building.
- hanniabu 11y agoThat's true for a warehouse or similar scenario. I believe the parent was talking about in a greenhouse. You can layer to a degree and then you only need supplemental lighting for the understories.
- fweespeech 11y agoYou are ignoring the fact a farm space isn't 100% plants. You need spaces for workers to move and so forth. Lets say you have 3 stories, of which the "center" of the bottom 2 is used for workers. You still get additional space compared to a single story for the same land cost. If the cost of construction is less than the cost of land, it works perfectly [as is the case in singapore]. About a third of a farm is just space for the workers to move around and harvest things We are talking literally single light bulb is all the supplemental light you need which isn't what your blog post you linked to is willing to admit. http://www.skygreens.com/ http://www.skygreens.com/ You can see how they layer things in the image, the limits really aren't there in the way you imply in high-land-cost areas.
- maliker 11y agoI see how skygreens can produce high-value crops that don't require much light in a small amount of space. But they're still using a lot of energy that isn't required in conventional farming. What is their energy input per kCalorie produced?