The Vertical Farm(newyorker.com)
newyorker.com
The Vertical Farm
http://www.newyorker.com/magazine/2017/01/09/the-vertical-farm
39 comments
The water issue is independent of whether the farm is vertical or not. There are plenty of hydroponic farms that are in a traditional horizontal orientation, I presume aeroponics can be setup this way as well. So, I do think the smaller area is the main advantage, though I'm not convinced it is a compelling enough reason given the increased energy, land and capital costs.
I agree that water should be treated as more valuable and scarce than it currently is. You mentioned the Middle East, I saw this concept for a "seawater greenhouse" recently in Qatar and was intrigued
http://www.sciencemag.org/news/2013/11/desert-farming-experi...
In the US, I'm curious about the scalability of these water saving technologies. Could they replace a significant percentage of vegetable production of drought stricken California? As I understand it now, hydroponics is used primarily for winter production, even that competes with Colorado River dependent Arizona.
I agree that water should be treated as more valuable and scarce than it currently is. You mentioned the Middle East, I saw this concept for a "seawater greenhouse" recently in Qatar and was intrigued
http://www.sciencemag.org/news/2013/11/desert-farming-experi...
In the US, I'm curious about the scalability of these water saving technologies. Could they replace a significant percentage of vegetable production of drought stricken California? As I understand it now, hydroponics is used primarily for winter production, even that competes with Colorado River dependent Arizona.
You are absolutely correct about that the water aspect is not vertical related in any way. I'm just used to seeing vertical and aeroponics going so hand-in-hand that I totally forgot about the possibility to have horizontal aeroponic greenhouses.
I'm very curious as well about all of these water reducing efforts, since that may well be the largest thing that threatens the food supply in the coming decades.
I'm very curious as well about all of these water reducing efforts, since that may well be the largest thing that threatens the food supply in the coming decades.
It's probably still cheaper energy-wise to clean those polluted rivers first.
I agree at some point we must start thinking about reusing agriculture water¹. But doing that when there's a perfectly good river nearby that you don't want to use just because it's polluted seems premature.
1 - Does it imply in vertical? And what would be the impact of not throwing that water at the atmosphere anymore?
I agree at some point we must start thinking about reusing agriculture water¹. But doing that when there's a perfectly good river nearby that you don't want to use just because it's polluted seems premature.
1 - Does it imply in vertical? And what would be the impact of not throwing that water at the atmosphere anymore?
Right, but then we're really talking about aeroponic farming, not vertical farming.
But the vast majority of vertical farms are aeroponic farms, are they not?
It's way more efficient to do aeroponic if you are vertical farming, and it's way more efficient to do vertical if you are aeroponic farming. The two work together.
It's way more efficient to do aeroponic if you are vertical farming, and it's way more efficient to do vertical if you are aeroponic farming. The two work together.
"The willingness of a certain kind of customer to pay a lot for salad justifies the investment." It's a hipster thing.
The greens thing may not scale. With salad greens, most of what you grow is salable product. With most vegetables, you grow a lot of plant that gets discarded.
There have been companies doing vertical farming in Japan for a few years, but they're mostly lettuce factories. There's one operation in Japan growing strawberries, but "they are currently selling their medium size strawberries at around $5 per berry, not per package. They only sell through their own channels or at high-end department stores in Tokyo, and they admit that their product is not for people to purchase at supermarkets for daily consumption, but a luxury product for gifts."
There's talk of vertical farming for tomatoes, but nobody seems to be doing this profitably on a significant scale.
The greens thing may not scale. With salad greens, most of what you grow is salable product. With most vegetables, you grow a lot of plant that gets discarded.
There have been companies doing vertical farming in Japan for a few years, but they're mostly lettuce factories. There's one operation in Japan growing strawberries, but "they are currently selling their medium size strawberries at around $5 per berry, not per package. They only sell through their own channels or at high-end department stores in Tokyo, and they admit that their product is not for people to purchase at supermarkets for daily consumption, but a luxury product for gifts."
There's talk of vertical farming for tomatoes, but nobody seems to be doing this profitably on a significant scale.
This probably makes sense in Japan more than anywhere else.
There's an active market for small numbers of near perfect fruit attractively packaged and sold for use as gifts.
$5 is still on the high-side. But a pack of perhaps 8 fruit for 30USD is pretty normal. You'd actually find that in a lot of supermarkets in Tokyo and beyond, not just very high end places.
There's an active market for small numbers of near perfect fruit attractively packaged and sold for use as gifts.
$5 is still on the high-side. But a pack of perhaps 8 fruit for 30USD is pretty normal. You'd actually find that in a lot of supermarkets in Tokyo and beyond, not just very high end places.
Tomato production in greenhouses is already vertical if you consider that the plants are grown up to 6m (20ft) high. The plant length at the end of the growing period is roundabout 15m-20m (50-65ft), since the plants are treated in a way that keeps one main branch growing at the top while pruning everything below harvest line.
https://s-media-cache-ak0.pinimg.com/originals/19/c4/53/19c4...
https://s-media-cache-ak0.pinimg.com/originals/19/c4/53/19c4...
First, "hispter thing" doesn't mean a thing.
And for the profitability, it may improve through time, so this kind of farms should be not discarded. Electric cars are mostly a luxury for now, but it will clearly comme to mass market soon. For a lot of products, it is neccessary to sell it as a luxury first to be able to improve the process enough to make it available to all.
Yes, "hipster thing" does mean something:
It means an experimental, short-term foray into something very few people are doing and which is currently non-sensical or unprofitable and whose near-term potential is unknown.
That experimental willingness for a small group to take something on without knowing always been a feature of humanity and the essence of the hacker spirit.
If one wishes to abstain from any such trend, it's certainly their prerogative to dismiss it simply as a "hipster thing." There is little need for than a few rare people to try it out. This doesn't mean that anything "hipster" should ever be taken as a shorthand for "bad," which often happens in poor sources of information.
We tend to dismiss "hipsters" because we deride their lack of cohesion and perceive it as an assault on our values. Finally, our derision is ironically necessary because it gives the hipsters the necessary challenge to evaluate an idea, process, technology or way of life from a non-idealized perspective. "You may like that fixie, but it is good enough that when everyone is laughing at you, you'll still ride it?"
Anyway: vertical farming in urban centers is foolishness. The real estate is simply too valuable. NYC already has a 10% tax. This is a grad school trope and NGO scam with base-level appeal to hippies
It means an experimental, short-term foray into something very few people are doing and which is currently non-sensical or unprofitable and whose near-term potential is unknown.
That experimental willingness for a small group to take something on without knowing always been a feature of humanity and the essence of the hacker spirit.
If one wishes to abstain from any such trend, it's certainly their prerogative to dismiss it simply as a "hipster thing." There is little need for than a few rare people to try it out. This doesn't mean that anything "hipster" should ever be taken as a shorthand for "bad," which often happens in poor sources of information.
We tend to dismiss "hipsters" because we deride their lack of cohesion and perceive it as an assault on our values. Finally, our derision is ironically necessary because it gives the hipsters the necessary challenge to evaluate an idea, process, technology or way of life from a non-idealized perspective. "You may like that fixie, but it is good enough that when everyone is laughing at you, you'll still ride it?"
Anyway: vertical farming in urban centers is foolishness. The real estate is simply too valuable. NYC already has a 10% tax. This is a grad school trope and NGO scam with base-level appeal to hippies
Very interesting. A couple of thoughts:
1. How about automating harvesting? The article suggests that there is a fairly sizeable unskilled workforce, potentially involved in harvesting, packing etc. I think I read elsewhere that the costs involved in this are relatively low and that there might be little cost benefit in automating. However, an automated solution could potentially have other benefits, e.g. opportunity for a "pick on demand fresh for me at the time I schedule" option, e.g. via an app (assuming automated inventory etc.). Going one step further, if you had automated planting, pruning etc. you might even be able to create "black boxes" which would in effect be fresh produce vending machines.
2. Does this scale to larger perennial plants, e.g. fruit trees? If vertical farming is only viable for salad greens (where you harvest pretty much the entire plant and then start again), not just from a cost perspective (value per kilo of produce, frequency of harvests, space occupied by plants, etc.) but also from a practical perspective (e.g. does aeroponics even work for trees - a quick read of wikipedia is inconclusive) then it isn't going to make the world a better place.
1. How about automating harvesting? The article suggests that there is a fairly sizeable unskilled workforce, potentially involved in harvesting, packing etc. I think I read elsewhere that the costs involved in this are relatively low and that there might be little cost benefit in automating. However, an automated solution could potentially have other benefits, e.g. opportunity for a "pick on demand fresh for me at the time I schedule" option, e.g. via an app (assuming automated inventory etc.). Going one step further, if you had automated planting, pruning etc. you might even be able to create "black boxes" which would in effect be fresh produce vending machines.
2. Does this scale to larger perennial plants, e.g. fruit trees? If vertical farming is only viable for salad greens (where you harvest pretty much the entire plant and then start again), not just from a cost perspective (value per kilo of produce, frequency of harvests, space occupied by plants, etc.) but also from a practical perspective (e.g. does aeroponics even work for trees - a quick read of wikipedia is inconclusive) then it isn't going to make the world a better place.
> However, an automated solution could potentially have other benefits, e.g. opportunity for a "pick on demand fresh for me at the time I schedule" option, e.g. via an app (assuming automated inventory etc.).
If the pick-up times are at reasonable times (not 3 a.m.), they would already have people on site. The system could tell them to pick X amount of plant Y. So "on demand" doesn't necessarily mean "no humans involved".
> Going one step further, if you had automated planting, pruning etc. you might even be able to create "black boxes" which would in effect be fresh produce vending machines.
From the article and the company's website it seems that the growing cloths must be washed from time to time, possibly after each harvest. I guess you wouldn't want to build a washing machine into the system, but it might be done...
> Does this scale to larger perennial plants, e.g. fruit trees?
Even if this system doesn't do that, growing trees indoors might be interesting from the perspectives of controlling temperature, wind, and especially water runoff/evaporation.
> salad [...] isn't going to make the world a better place
You might say the same thing about fruit trees. The key crops would probably be legumes and rice.
If the pick-up times are at reasonable times (not 3 a.m.), they would already have people on site. The system could tell them to pick X amount of plant Y. So "on demand" doesn't necessarily mean "no humans involved".
> Going one step further, if you had automated planting, pruning etc. you might even be able to create "black boxes" which would in effect be fresh produce vending machines.
From the article and the company's website it seems that the growing cloths must be washed from time to time, possibly after each harvest. I guess you wouldn't want to build a washing machine into the system, but it might be done...
> Does this scale to larger perennial plants, e.g. fruit trees?
Even if this system doesn't do that, growing trees indoors might be interesting from the perspectives of controlling temperature, wind, and especially water runoff/evaporation.
> salad [...] isn't going to make the world a better place
You might say the same thing about fruit trees. The key crops would probably be legumes and rice.
This is a great story. I - for one - hope that this technology and method of growing (provided it stays nice and healthy) succeeds. As a side benefit, if other competitors rise up and begin populating old, large metros (that were titans of jobs and industries decades ago), like Detroit, etc...well, that's another great benefit! Imagine all the jobs created, and not for getting more people to click things on the web. Also, I hear all the time that we need more farmers (to keep up with increased need for food growth), and yet others stating that we need more technologists/engineers (to solve some vexing human problems)...This farming technology appears to be a confluence of a need for a merged type of worker: the techno-farmer! Crazy, eh? But, I think, very cool.
You still think that salades are grown on, as we call it in Holland, full ground? This is how its done now, 5 layers on top of each other and no more dirty ground. http://www.food-nutrition.nl/artikelen/groenteteelt-op-een-h...
The combo is high yield, fast growth, good price and dense areas (as in, you can serve your market on a bike). I did not yet run the numbers, but I think it can be profitable. Take rucola, which grows very fast, if you can make 0.5kg per square meter every 2 weeks, then it's eur ~1.25 (1kg = ~5 euros) per square meter per week. With 10,000 m2, it's eur 12.5k per week. 10,000 m2 is a 100x100m square - not much, you can probably rent that much worth of loan in residential areas and pay in vegetables (1 box per week, etc.).
I think this is pretty doable. Go to market is pretty much done. Good story for being local, etc. Probably even tastier product if you know how to play with a greenhouse.
I think this is pretty doable. Go to market is pretty much done. Good story for being local, etc. Probably even tastier product if you know how to play with a greenhouse.
maybe one of those farms could directly replace the produce aisle of the supermarket. the benefit is that unsold produce would just get bigger.
Reminds me of Toshiba, and their project to repurpose semiconductor facilities to grow vegetables:
http://www.cleanroomtechnology.com/news/article_page/Toshiba...
http://www.cleanroomtechnology.com/news/article_page/Toshiba...
Most of America’s baby greens are grown in irrigated fields in the Salinas Valley, in California. During the winter months, some production moves to similar fields in Arizona or goes even farther south, into Mexico. If you look at the shelves of baby greens in a store, you may find plastic clamshells holding five ounces of greens for $3.99 (organicgirl, from Salinas), or for $3.29 (Earthbound Farm, from near Salinas), or for $2.99 (Fresh Attitude, from Quebec and Florida). Harwood’s magic number of eight dollars a pound would be on the cheap side today. Four dollars for five ounces comes to about thirteen dollars a pound.
AeroFarms supplies greens to the dining rooms at the Times, Goldman Sachs, and several other corporate accounts in New York. At the moment, the greens can be purchased retail only at two ShopRite supermarkets, one on Springfield Avenue in Newark and the other on Broad Street in Bloomfield. The AeroFarms clamshell package (clear plastic, No. 1 recyclable) appears to be the same size as its competition’s but it holds slightly less—4.5 ounces instead of five. It is priced at the highest end, at $3.99. The company plans to have its greens on the shelves soon at Whole Foods stores and Kings, also in the local area. Greens that come from California ride in trucks for days. The driving time from AeroFarms’ farm to the Newark ShopRite is about eleven minutes.
All of this makes sense. People will pay a premium for fresh produce and herbs, particularly if growing them close to consumption means that you can optimize for deliciousness rather than for transport-durability and long shelf life. I expect vertical farming to work well in this niche.
But the rest of it -- feeding all of New York City using just the space available in NYC, "Feeding the World in the 21st Century", "what might come of it when we’re nine billion humans on a baking, thirsting globe?" -- that's nonsense. For staple crops that provide most of the calories in a vegetarian diet, there is no net economic or environmental benefit to vertical farming. And there are good reasons to suspect that there will never be such benefits even as the technology evolves.
It's the vertical stacking of greenhouses that doesn't make sense outside of a high-priced freshness niche, and that's because of the requirement for artificial lighting. Artificial lighting is a very expensive way to drive photosynthesis compared to natural sunlight, and remains more expensive even with optimistic assumptions about future LED efficiency and falling costs for clean electricity. The energy requirements to grow e.g. soybeans in a vertical farm inside the NYC city limits wipe out all the environmental benefits of "locavorism," compared to just transporting them from the Midwest like usual. And New York has one of the cleaner electricity mixes in the US. It's worse if you use a fossil-heavy mix to power the lights.
I could see large scale use of greenhouses in the future, particularly things like this: http://www.sundropfarms.com/
Greenhouses and perhaps soil-free growing may be great ways to produce food in places that face extreme weather or lack soil or natural precipitation. But one level construction only, illuminated by natural sunlight. You can ship a ton of dried beans or wheat across oceans for significantly less energy than it takes to grow the same calories locally via artificial illumination.
AeroFarms supplies greens to the dining rooms at the Times, Goldman Sachs, and several other corporate accounts in New York. At the moment, the greens can be purchased retail only at two ShopRite supermarkets, one on Springfield Avenue in Newark and the other on Broad Street in Bloomfield. The AeroFarms clamshell package (clear plastic, No. 1 recyclable) appears to be the same size as its competition’s but it holds slightly less—4.5 ounces instead of five. It is priced at the highest end, at $3.99. The company plans to have its greens on the shelves soon at Whole Foods stores and Kings, also in the local area. Greens that come from California ride in trucks for days. The driving time from AeroFarms’ farm to the Newark ShopRite is about eleven minutes.
All of this makes sense. People will pay a premium for fresh produce and herbs, particularly if growing them close to consumption means that you can optimize for deliciousness rather than for transport-durability and long shelf life. I expect vertical farming to work well in this niche.
But the rest of it -- feeding all of New York City using just the space available in NYC, "Feeding the World in the 21st Century", "what might come of it when we’re nine billion humans on a baking, thirsting globe?" -- that's nonsense. For staple crops that provide most of the calories in a vegetarian diet, there is no net economic or environmental benefit to vertical farming. And there are good reasons to suspect that there will never be such benefits even as the technology evolves.
It's the vertical stacking of greenhouses that doesn't make sense outside of a high-priced freshness niche, and that's because of the requirement for artificial lighting. Artificial lighting is a very expensive way to drive photosynthesis compared to natural sunlight, and remains more expensive even with optimistic assumptions about future LED efficiency and falling costs for clean electricity. The energy requirements to grow e.g. soybeans in a vertical farm inside the NYC city limits wipe out all the environmental benefits of "locavorism," compared to just transporting them from the Midwest like usual. And New York has one of the cleaner electricity mixes in the US. It's worse if you use a fossil-heavy mix to power the lights.
I could see large scale use of greenhouses in the future, particularly things like this: http://www.sundropfarms.com/
Greenhouses and perhaps soil-free growing may be great ways to produce food in places that face extreme weather or lack soil or natural precipitation. But one level construction only, illuminated by natural sunlight. You can ship a ton of dried beans or wheat across oceans for significantly less energy than it takes to grow the same calories locally via artificial illumination.
> Artificial lighting is a very expensive way to drive photosynthesis compared to natural sunlight, and remains more expensive even with optimistic assumptions about future LED efficiency and falling costs for clean electricity.
What if we are talking theoretical limits instead of what is practical today?
Couldn't capturing the full spectrum of sunlight (e.g. through multi-junction cells) and then emitting an optimized spectrum for plants to absorb boost efficiency?
Photosynthesis efficiency is also affected by temperature. So at least in hot climates having the plants indoors while capturing the sunlight outside could yield increased efficiency when compared to fields exposed to direct sunlight.
What if we are talking theoretical limits instead of what is practical today?
Couldn't capturing the full spectrum of sunlight (e.g. through multi-junction cells) and then emitting an optimized spectrum for plants to absorb boost efficiency?
Photosynthesis efficiency is also affected by temperature. So at least in hot climates having the plants indoors while capturing the sunlight outside could yield increased efficiency when compared to fields exposed to direct sunlight.
A very informed and informative lecture filled with facts that supports the former argument:
https://www.youtube.com/watch?v=ISAKc9gpGjw
Myself I am a chemical engineer working in agricultural research. We are working on aquaponics and also test vertical growbeds. Vertical growbeds underperform significantly unless you put expensive light on them.
Generating the electricity for light through PV uses about ten times the area compared to using direct sunlight. No way to counter that by using the full spectrum.
Myself I am a chemical engineer working in agricultural research. We are working on aquaponics and also test vertical growbeds. Vertical growbeds underperform significantly unless you put expensive light on them.
Generating the electricity for light through PV uses about ten times the area compared to using direct sunlight. No way to counter that by using the full spectrum.
Except that you can transport the electricity much cheaper and with less pollution than you can the produce, and optimize the produce for things other than overcoming transport effects/concerns. So the PV installations can be far away on cheap land while the produce is grown right in the city where it's consumed.
Not saying it's a good idea, just that it seems there are some offsetting concerns.
Not saying it's a good idea, just that it seems there are some offsetting concerns.
Except what you say is not exactly true. Transportation losses for electricity are roundabout 25% - 30%. For a good comparison it makes sense to compare area efficiency. Plants in green houses can use 95% - 97% of direct sunlight depending on glazing type. Artificial lighting has the following calculation:
* 25% PV efficiency best case * 75% transport efficiency * 50% LED light efficiency best case
This amounts to a total area efficiency of 9.5%. So artificial light has a ten times worse area efficiency compared to using direct sunlight.
Transport energy consumption for the product on the other hand is often over estimated. Transporting amounts to something between 1% - 5% of the total energy cost of produce, depending on type and distance of course.
The vertical farm fallacy lies in the assumption that area is the scarce resource. This is simply not true if you move outside the city borders. Area within the city is very valuable and incredibly expensive. Even if you only pay a comparably low rent, lets say 2.5$/sqm (25ct/sqft), that amounts to ~30.000$ rent per year (for a 1000sqm indoor farm). You can buy farmland for this amount of money and forward from that the cost for area is not there any more.
In my (our faculty) opinion the sweet spot for urban farming ist in the peri urban part around the city. Area is still cheap, you can use direct sunlight with little or no artificial light and transportation cost and energy can be slashed by 90%.
Depending on the industry in that area there may even be some synergy potentials with residual heat and other materials (eg. compostable stuff from near by production).
Dutch Prof. P. Smeets proposes argoparks as a sustainable urban agriculture concept. We are in favour of that.
Edit: Clarified on indoor farm area.
* 25% PV efficiency best case * 75% transport efficiency * 50% LED light efficiency best case
This amounts to a total area efficiency of 9.5%. So artificial light has a ten times worse area efficiency compared to using direct sunlight.
Transport energy consumption for the product on the other hand is often over estimated. Transporting amounts to something between 1% - 5% of the total energy cost of produce, depending on type and distance of course.
The vertical farm fallacy lies in the assumption that area is the scarce resource. This is simply not true if you move outside the city borders. Area within the city is very valuable and incredibly expensive. Even if you only pay a comparably low rent, lets say 2.5$/sqm (25ct/sqft), that amounts to ~30.000$ rent per year (for a 1000sqm indoor farm). You can buy farmland for this amount of money and forward from that the cost for area is not there any more.
In my (our faculty) opinion the sweet spot for urban farming ist in the peri urban part around the city. Area is still cheap, you can use direct sunlight with little or no artificial light and transportation cost and energy can be slashed by 90%.
Depending on the industry in that area there may even be some synergy potentials with residual heat and other materials (eg. compostable stuff from near by production).
Dutch Prof. P. Smeets proposes argoparks as a sustainable urban agriculture concept. We are in favour of that.
Edit: Clarified on indoor farm area.
Transport efficiency for electricity is way higher than 75%. Total transmission losses are around 7% in the US. Plant efficiency is worse than 95%, because chlorophyll only responds to certain wavelengths well. LED lighting for plant growth doesn't use white LEDs.
Ok, I was not aware that there has been a lot of progress on reducing transport losses in the electricity grid over the last decades. Thanks for the heads up! But even taking this into account area efficiency of direct sunlight compared to artificial light still differs significantly (25% * 95% * 50% = 12%).
Plants actually _do_ use the green light of the spectrum, just not as much, thus leaves appear in green color. How high would you estimate the efficiency gain by using a better spectrum? My guess would be that this gain would be below 50%. So area efficiency of artificial light would still be below 20%. And the calculation has been made "best case". 25% photovoltaic efficiency are lab figures for the very best cells possible. Installed base is lower still, monocrystallin cells 20 - 22 %, polycrystallin 15 - 20 %.
Plants actually _do_ use the green light of the spectrum, just not as much, thus leaves appear in green color. How high would you estimate the efficiency gain by using a better spectrum? My guess would be that this gain would be below 50%. So area efficiency of artificial light would still be below 20%. And the calculation has been made "best case". 25% photovoltaic efficiency are lab figures for the very best cells possible. Installed base is lower still, monocrystallin cells 20 - 22 %, polycrystallin 15 - 20 %.
You can have the plants indoors and protected from temperature extremes in a single story greenhouse with natural illumination.
Theoretically, an infinite-junction solar cell can achieve up to 68.7% efficiency under non-concentrated sunlight. The best demonstrated so far is about half of that: https://www.sciencedaily.com/releases/2016/05/160517121811.h...
Efficiency under concentrated illumination is higher but concentrating designs require direct illumination and have their performance fall off a cliff under even partially cloudy conditions.
Spectral tuning of the light sources can make illumination more photosynthetically efficient, and so can evening out the illumination intensity. If you could get lights and multi-junction solar cells that operated at the theoretical limit it might be more efficient than natural sunlight growing, but that's a tall order to achieve in practice. To achieve a net environmental benefit not only does it have to be more efficient than single-story natural illuminated structures, it has to be enough more efficient to pay back the environmental costs of manufacturing the extra equipment required up-front in the vertical case.
Theoretically, an infinite-junction solar cell can achieve up to 68.7% efficiency under non-concentrated sunlight. The best demonstrated so far is about half of that: https://www.sciencedaily.com/releases/2016/05/160517121811.h...
Efficiency under concentrated illumination is higher but concentrating designs require direct illumination and have their performance fall off a cliff under even partially cloudy conditions.
Spectral tuning of the light sources can make illumination more photosynthetically efficient, and so can evening out the illumination intensity. If you could get lights and multi-junction solar cells that operated at the theoretical limit it might be more efficient than natural sunlight growing, but that's a tall order to achieve in practice. To achieve a net environmental benefit not only does it have to be more efficient than single-story natural illuminated structures, it has to be enough more efficient to pay back the environmental costs of manufacturing the extra equipment required up-front in the vertical case.
I was particularly thinking about applications in arid climates. Where just spraying water on plants or cooling large greenhouses has inefficiencies on its own.
Or is cooling horizontal greenhouses easy enough, even in deserts?
Or is cooling horizontal greenhouses easy enough, even in deserts?
The Sundrop Farms approach pumps seawater through an evaporative structure to control the temperature inside a greenhouse in a desert climate. That way the salt doesn't get on the plants but you only need a little electricity to run the cooling system. In a desert far inland you need extra piping/pumping or a more expensive cooling system, but I still can't see a terrestrial scenario where artificial-illumination greenhouses provides calories at a lower environmental or financial cost than natural sunlight greenhouses or fields.
Artificial illumination farming of course does make sense for crewed deep space missions because there's not any other option. That's actually how I first started thinking about this problem -- "what if you wanted to feed a crewed nuclear powered outpost in orbit around Neptune?" It turns out that it takes a lot of electricity to feed people that way because our food crops suck at turning light-energy into human-edible energy. Having a rough idea of the enormous electricity expenditures, I started doing double-takes when vertical farm enthusiasm started spreading a few years ago.
Artificial illumination farming of course does make sense for crewed deep space missions because there's not any other option. That's actually how I first started thinking about this problem -- "what if you wanted to feed a crewed nuclear powered outpost in orbit around Neptune?" It turns out that it takes a lot of electricity to feed people that way because our food crops suck at turning light-energy into human-edible energy. Having a rough idea of the enormous electricity expenditures, I started doing double-takes when vertical farm enthusiasm started spreading a few years ago.
I'm lucky enough to be able to purchase Sundrop-grown tomatoes[1] (or at least I'm pretty sure they are Sundrop) and can confirm they are both price competitive (as in they are always the cheapest option) and taste great.
[1] http://www.abc.net.au/news/2016-10-01/sundrop-farms-opens-so...
[1] http://www.abc.net.au/news/2016-10-01/sundrop-farms-opens-so...
If we are talking theoretical limits instead of what is practical today, we may as well count on nuclear fusion to power it.
> Artificial lighting is a very expensive way to drive photosynthesis compared to natural sunlight
No, that's not necessarily true.
Sunlight is actually fairly wasteful when landing on a leaf. It goes across a wide band of frequencies, most of which aren't used by the plant. And lots of it scatters on the earth near the plant, also unused. Finally, the solar irradiation is almost always larger than the total energy a plant could absorb, even if it were the perfect frequencies.
Solar panels turn a much higher percentage of that falling energy into electricity. By re-emitting only the frequencies best absorbed by the plants, and having a much denser planting than would be possible outdoors, and, most importantly, only providing each plant with the light it needs, you can take that huge volume of "wasted" solar energy and use it to grow many more plants.
So if you take all the sunlight that is falling on the roof of the farm, even after you account for all the conversion losses you can still come out ahead because you're using the remaining energy in a much more efficient manner for plant growth.
Plants only need in the order of 10-100 W/m^2 in order to grow. A solar panel, however, easily generates 200 W/m^2 and more. Therefore, a 1m^2 solar panel can support the needs of > 1m^2 of plants, even before taking into account the spectrum efficiencies.
No, that's not necessarily true.
Sunlight is actually fairly wasteful when landing on a leaf. It goes across a wide band of frequencies, most of which aren't used by the plant. And lots of it scatters on the earth near the plant, also unused. Finally, the solar irradiation is almost always larger than the total energy a plant could absorb, even if it were the perfect frequencies.
Solar panels turn a much higher percentage of that falling energy into electricity. By re-emitting only the frequencies best absorbed by the plants, and having a much denser planting than would be possible outdoors, and, most importantly, only providing each plant with the light it needs, you can take that huge volume of "wasted" solar energy and use it to grow many more plants.
So if you take all the sunlight that is falling on the roof of the farm, even after you account for all the conversion losses you can still come out ahead because you're using the remaining energy in a much more efficient manner for plant growth.
Plants only need in the order of 10-100 W/m^2 in order to grow. A solar panel, however, easily generates 200 W/m^2 and more. Therefore, a 1m^2 solar panel can support the needs of > 1m^2 of plants, even before taking into account the spectrum efficiencies.
Yes totally agree, on a per calorie basis, this will never be viable (you get almost no calories from greens). Staple crops will always need a lot of land, but they may find a niche for greens, more power to them.
with the obesity epidemic calorie density should be the least of our worries.
Even if you're obese you still need calories from the base of your diet. Put another way, you aren't going to live on lettuce and kale alone.
if you ate lettuce and kale as much as an obese person eats chips, you'd be very healthy.
Um... I'm going to treat this as though you're serious. You're probably wrong here. Lettuce especially is pretty lacking in nutrients, and all of the good stuff in kale is locked inside thick cell walls that have to be broken mechanically or by heat. Moreover, you're assuming that someone is fat specifically because of chips, when they probably make a number of unhealthy choices that cumulatively lead to obesity. I'm not sure a 1 to 1 swap of kale for chips buys you much more than a sore jaw and very regular bowels.
I predict that in the near future the overlap of psychoneuroimmunology and gut flora is going to have a lot to say about regular, well-formed, easy to pass, mid to dark-brown, sinking, bowel movements.
I would like to address this from a slightly different perspective. Energy is the great enabler. With sufficiently cheap energy this could be viable, possibly even for staple crops. In addition, cheaper energy would make available many other processes which are currently cost-prohibitive and greatly assist in raising the standard of living of every human on the planet.
Too much attention is given to classifying energy sources as "renewable" or "green", rather than the less restrictive criteria of sustainability and cost.
As an example, fission power with a closed fuel cycle, using either uranium or thorium and possibly incorporating seawater extraction could accomodate all of humanity's energy demands for hundreds of millenia at current consumption rates. Nuclear power is already fairly cheap, but I do not think it overly optimistic to expect that economies of scale and automation could make it much cheaper. Yet the United States still refuses to even reprocess spent fuel, and one of the most promising projects -- the Integral Fast Reactor -- was cancelled in 1992 by the Clinton presidency when it was almost complete.
Too much attention is given to classifying energy sources as "renewable" or "green", rather than the less restrictive criteria of sustainability and cost.
As an example, fission power with a closed fuel cycle, using either uranium or thorium and possibly incorporating seawater extraction could accomodate all of humanity's energy demands for hundreds of millenia at current consumption rates. Nuclear power is already fairly cheap, but I do not think it overly optimistic to expect that economies of scale and automation could make it much cheaper. Yet the United States still refuses to even reprocess spent fuel, and one of the most promising projects -- the Integral Fast Reactor -- was cancelled in 1992 by the Clinton presidency when it was almost complete.
For example in areas like the Middle-East, agricultural irrigation takes a huge and increasing toll on the water resources [1]. This along with the large rivers of the world (where the irrigation water usually comes from) being constantly more polluted may well increase tensions in these arid regions.
If by vertical farming techniques the need for water can be reduced as dramatically as the article states ("Aeroponic farming uses about seventy per cent less water than hydroponic farming, which grows plants in water; hydroponic farming uses seventy per cent less water than regular farming"), this by itself seems like a worthy effort for certain regions on the planet.
[1] http://www.fao.org/docrep/003/Y1860E/y1860e05.htm