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Vertical farming does not save space

lowtechmagazine.com

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Re: Vertical farming does not save space

#61

Post by hctaw »

worker767424 wrote: post #42

Vertical farming mostly feels like a solution in search of a problem. It uses relatively expensive technology to produce low-value products. Putting seeds in the ground, tilling, and waiting is absurdly cheap compared to building growhouses. For some perspective, what farms actually do extend growing seasons is put "greenhouses" around cold-sensitive crops like tomatoes, but a "greenhouse" in this case is a wire hoop…

The greater problem to solve is maximizing nutrition for communities while minimizing the carbon costs of providing it. Vertical farms fit into that equation by moving production closer to the people that eat the produce, and making it more available to food/nutrition deserts in urban areas.

Extending growing seasons or returning farmlands to wildlands miss that point. The bigger problem in the latter is livestock anyway.

Re: Vertical farming does not save space

#62

Post by farisjarrah »

pydry wrote: post #50
worker767424 wrote: post #42

Vertical farming mostly feels like a solution in search of a problem. It uses relatively expensive technology to produce low-value products. Putting seeds in the ground, tilling, and waiting is absurdly cheap compared to building growhouses. For some perspective, what farms actually do extend growing seasons is put "greenhouses" around cold-sensitive crops like tomatoes, but a "greenhouse" in this case is a wire hoop…

It's a solution for taking trucks off the road and avoiding waste from spoiled produce. It's not a solution for saving land.

If a vertical farm scales up and sells their produce to a super market, dont they still have to package up all the food and ship it on trucks before it gets to the end user?

Re: Vertical farming does not save space

#63

Post by kibwen »

the_gastropod wrote: post #57
SimianLogic2 wrote: post #43

This article is more about indoor farming than vertical farming (is it even vertical if there's only one row?). I grow lettuce indoors. It serves as a nice houseplant and fresh source of salad greens for lunch. It's fairly new, so the cost isn't that much different than just buying lettuce. Once I start building my own "pods" instead of buying the brand-name pods, though, I expect it'll be a bit cheaper than buying 4…

I understood the point to be more about the energy inputs. The gist of it is: plants are more efficient at capturing energy from the sun directly than indirectly via solar panels -> light bulbs -> plants (which seems obvious, when you state it that way). The only thing that makes vertical farming make any financial sense, today, is the access to cheap (subsidized) fossil fuels.

> plants are more efficient at capturing energy from the sun than solar panels -> light bulbs -> plants are

This is a counterintuitive misconception that I mention elsewhere in this thread. Plants aren't optimized for raw sunlight utilization, because that's not the bottleneck for growth or survival. Plants deliberately reflect away 90% of the sun's energy (https://en.wikipedia.org/wiki/Photosynthetic_efficiency) because other factors are more important: https://www.quantamagazine.org/why-are-plants-green-to-reduc...

Re: Vertical farming does not save space

#65

Post by nfin »

maxharris wrote: post #59

Artificial lighting saves land because plants can be grown above each other, but if the electricity for the lighting comes from solar panels, then the savings are canceled out by the land required to install the solar panels. The vertical farm is a paradox unless fossil fuels provide the energy. In that case, there’s not much sustainable about it. This entire piece is based on the assumption that the only sources of…

One more thing it saves:

Transportation (!) from miles away, as a skyscraper could feed a city or a part of it.

Re: Vertical farming does not save space

#66

Post by cbmuser »

maxharris wrote: post #59

Artificial lighting saves land because plants can be grown above each other, but if the electricity for the lighting comes from solar panels, then the savings are canceled out by the land required to install the solar panels. The vertical farm is a paradox unless fossil fuels provide the energy. In that case, there’s not much sustainable about it. This entire piece is based on the assumption that the only sources of…

Yeah, don’t bother with reading articles that exclude the largest source of clean energy in US.

Such articles have an ideological bias.

Re: Vertical farming does not save space

#67

Post by Klwohu »

abeppu wrote: post #25
Klwohu wrote: post #10

It doesn't grow many crops, either. I can see it being useful for restricted spaces like balconies or roof top gardens in cities, also because unlike soil gardening the weight is much less even accounting for the hydroponic growing solution. And of course, the gem of the new "industry," the place in Jackson which is a special case, tucked away up in the mountains where it can be hard to get in and out without delays,…

My understanding was part of the reason we get bland veggies in the supermarket is that selection has been for being able to stay good for a longer period and not be damaged during shipping. If vertical farms have less time between harvesting and actual eating, maybe we can pick tastier varietals?

What if the taste of the particular strain isn't what causes blandness, but growing it in water with plant food mix instead of soil is? It might be possible to develop choose tastier breeds for hydroponic use but it's likely that even they would taste even better if grown in real soil on a farm, with all the added nutrient intake that sustains.

So far the most success has been with fast-growing salad mixes and such, and to me it resembles an offshoot of the fresh sprout industry more than a heavy lifting type of agriculture meant to sustain the billions.

Re: Vertical farming does not save space

#68

Post by bee_rider »

the_gastropod wrote: post #57
SimianLogic2 wrote: post #43

This article is more about indoor farming than vertical farming (is it even vertical if there's only one row?). I grow lettuce indoors. It serves as a nice houseplant and fresh source of salad greens for lunch. It's fairly new, so the cost isn't that much different than just buying lettuce. Once I start building my own "pods" instead of buying the brand-name pods, though, I expect it'll be a bit cheaper than buying 4…

I understood the point to be more about the energy inputs. The gist of it is: plants are more efficient at capturing energy from the sun directly than indirectly via solar panels -> light bulbs -> plants (which seems obvious, when you state it that way). The only thing that makes vertical farming make any financial sense, today, is the access to cheap (subsidized) fossil fuels.

The cost of transporting the conventionally grown plants would have to be accounted for as well, but I'd be pretty surprised if that got anywhere near tipping the scale over to vertical farming.

Re: Vertical farming does not save space

#69

Post by klodolph »

kibwen wrote: post #52
klodolph wrote: post #28

Earlier quoted context omitted.

Solar panels can be more efficient, but if your comparison is between “sunlight -> plants” and “sunlight -> solar panels -> electric lights -> plants”, you have to include the actual efficiency of e.g. photovoltaics and LEDs in your calculations. Photovoltaics these days have something around 15-20% efficiency and LEDs have conversion efficiency around 50-60%. The magenta grow lamps are colored for more efficient use…

Yes, and I updated my comment just as you were posting this to mention losses due to reconversion. However, also keep in mind that even large efficiency losses can still lean in favor of photovoltaics/LEDs, because plants only use about 10% of the sun's energy in the first place.

The problem with talking about photosynthetic efficiency is that there are different endpoints you can talk about. The more efficient plants (C4 plants like sugarcane and maize) have something like 4% efficiency converting sunlight to biomass, but they actually absorb a 53% of the incoming light based on spectrum, and lose about 24% of the energy because photons with shorter wavelengths have excess energy which the plants cannot use. We’re not interested in the 4% figure, we’re interested in the 53% and 24% figure because they represent the part of the process that we can change.

Doing the math, that’s around 59% loss which you could mitigate by using LEDs that produce the correct spectrum—but solar panels and LEDs have 90% losses, so you’re noticeably worse off.

It’s worth remembering that the reason why plants only absorb certain parts of the spectrum is the same reason why photovoltaic panels only absorb certain parts of the spectrum—in both cases, you are using light to move electrons, and these processes only capture energy that corresponds to the underlying band gap. Light with shorter wavelengths has additional energy which is wasted, both for photovoltaics and for plants.

You can increase the efficiency by creating multijunction solar panels, which results in multiple band gaps. For most applications, these aren’t cost-effective. If I remember correctly, plants are also “multi-junction”, which explains why they are so efficient.

Re: Vertical farming does not save space

#70

Post by kapp_in_life »

farisjarrah wrote: post #62
pydry wrote: post #50

Earlier quoted context omitted.

It's a solution for taking trucks off the road and avoiding waste from spoiled produce. It's not a solution for saving land.

If a vertical farm scales up and sells their produce to a super market, dont they still have to package up all the food and ship it on trucks before it gets to the end user?

Yes but the idea is you are now shipping it 5 miles instead of 500 miles.
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