
Wheat yield potential in controlled-environment vertical farms - tosh
https://www.pnas.org/content/early/2020/07/21/2002655117
======
terramars
I like how this whole yield paper and model is based on the results of a 3'x3'
trial area...

"With artificial lighting increasing the intensity and duration of light
beyond what can be captured from the sun in a field, the short indoor growth
cycle produced mean grain yields of 14 ± 0.8 t/ha per harvest at 11% grain
moisture based on a 1-m2 edge-protected experimental area"

How tf can you say your yields are going to extrapolate from that tiny space
to a hectare scale facility? It's ridiculous. We have a huge problem achieving
lab-theoretical yields on working farms, outside of the super optimized and
most destructive conventional agriculture methods. They didn't even do a full
greenhouse trial. Come on guys, you can say it's promising but to say you can
get 1000+t/ha out of a vertical farm because of this is fantasy.

~~~
roenxi
Agronomics baffles me, so I'll admit to not having read the paper. But for
those of us just reading the comments, can someone expound on the complaint?
If the yields only work in tiny spaces, why can't the hectare scale facility
be divided up into tiny spaces? These are indoor farms, can't they just
replicate the lab conditions?

I can understand the argument "it isn't economic", but the process to make
something economic is do it once -> do it many times -> do it many times
cheaply, so the paper could be part of the process that ends with mass
vertical farming at absurd yields.

~~~
jsilence
It takes seven photons of the right energy band to make one photosynthesis
reaction. This is a hard constraint that can not be eliminated by upscaling.
Yield is hard coupled to light energy input. Agricullture is only feasible
because we receive a huge amount of photons from the sun for free.

Vertical farming is a pipe dream.

~~~
vermilingua
Yet they apparently achieved this in a lab. You didn’t explain why it can’t be
scaled.

~~~
tinco
GP is just restating the last sentence of the "Significance" section of the
paper in harsher words:

"However, given the high energy costs for artificial lighting and capital
costs, it is unlikely to be economically competitive with current market
prices."

There is a limited amount of sunlight hitting an area. That means to scale
crop yields by going vertical, you need artificial light.

At the moment energy is not harvested in a (sustainably) scalable manner, so
vertical farming is infeasible except to boost local production in rich
countries.

Saying it's a "pipe dream" is a bit too harsh imo, I think as energy demand
ramps up, and oil keeps going down eventually we will be forced to produce
unlimited amounts of cheap energy through nuclear power plants, but that's
just my vision for the future..

~~~
ianai
1\. I’m not convinced this has to be artificial light as fiber optics might be
able to pipe in plenty of sunlight.

2\. I’ve heard the real efficiency is tailoring light from high efficiency
leds per plant.

------
arminiusreturns
I think this sort of work is important because it gives us data to focus on
improving. Like solar power efficiencies, I think there is lots of room to
improve on vertical farming output which will be vital for a few reasons.

Reason one, is that I think one lesson we've learned and are still learning is
that the original model of the internet that senses damage and routes around
it is still a strong model, and I think the same applies to food. To reduce
the impact of food shortages, we need to get more people farming again
essentially, and a small vertical farm can be had for those people regardless
of if they have land or suitable land for traditional growing, and the cost
are likely to be similar to solar panels and be one that is subsidized at
first or at least given tax breaks.

Reason two is that I think the same work will be of vital importance for
future space faring missions. If we can get closed loop ecosystem
sustainability heavily improved we might be ready for something like a real
Mars trip/settlement etc. Personally I advocate for adding other systems to
the closed loop to feed off each other, aka auqoponics, etc to add a meat
source (fish) into the loop etc.

So we have a decent study on wheat. Now lets get the yield potentials for
everything else under the sun so we can start optimizing better. Probably end
up with focus on whatever has the highest calorie output to price to produce
ratio.

~~~
nradov
Food shortages are caused by natural disasters and political problems such as
wars, not by lack of places to grow crops. We have plenty of farmland and
farmers. If your vertical farm is caught in the middle of a war or flood then
it won't be able to operate.

~~~
pm90
Isn’t the idea here that every city would have a vertical farm close to it,
decentralizing the production of food? And if for various economic reasons
food does tend to be grown in clustered vertical farms, I imagine the know how
to do so would be widely disseminated and cities in particular would keep
aside dormant vertical farms as a measure of food security, to quickly scale
up in harder times.

I am not able to see how a network of distributed vertical food farms would be
less resilient to political disasters than growing everything in the Midwest.
Food production has been the foundation of every successful civilization, this
technology would potentially allow us to grow food without wrecking Earths
environment.

~~~
nradov
Have you ever even been to a farms in the Midwest? They are not centralized.
They are distributed over a large part of the country.

California and several other states are also net food exporters.

~~~
pbhjpbhj
Net by value, weight, calories, nutrition ..?

Farming enough grapes (as my late Uncle did in California), say, to balance
trade doesn't mean you could farm enough food in general.

------
brippalcharrid
Ultimately this is about removing the limitations of agriculture as it stands
(1 acre/acre, 1kw/m2, 330ppm CO2) so that we can convert energy and chemicals
into food in a scalable, reliable and repeatable way. This has obvious medium-
term applications outside of our atmosphere and gravity well, but if we allow
energy costs to come down by orders of magnitude by continuing to make
advances in nuclear energy, it will inevitably lead to a system that's
preferable in terms of land use, both in terms of former agricultural land
that can be returned to forests and relatively small high-density power plants
that will replace sprawling renewable infrastructure. I don't understand why
people keep bringing up the idea of using high-rise buildings in an
urban/near-urban environment; surely you'd want to do it in lights-out
factories on the cheapest available land, and if energy is cheap enough to
make vertical farming profitable, shipping costs would be negligible. A single
1km X 1km X 1km underground vertical farm could be sufficient to feed millions
of people while leaving the land above it available for
forests/grassland/tundra, or provide district heating to a sizeable
population.

~~~
nradov
We have plenty of land for growing crops. Land is not an issue.

~~~
X6S1x6Okd1st
We already use half of all habitable land for agriculture.

"The expansion of agriculture has been one of humanity’s largest impacts on
the environment. It has transformed habitats and is one of the greatest
pressures for biodiversity: of the 28,000 species evaluated to be threatened
with extinction on the IUCN Red List, agriculture is listed as a threat for
24,000 of them"

[https://ourworldindata.org/land-use](https://ourworldindata.org/land-use)

Do we really want to keep eating into what wilderness remains?

Just because we "have" it doesn't mean we should convert it.

We already produce enough food to feed the world and likely won't have trouble
producing enough food to feed the coming extra billions, but if we can focus
on increasing yeilds and moving away from raising animals for consumption we
can also reduce our footprint on the world.

~~~
tuatoru
> We already produce enough food to feed the world and likely won't have
> trouble producing enough food to feed the coming extra billions, but if we
> can focus on increasing yeilds and moving away from raising animals for
> consumption we can also reduce our footprint on the world.

If we want to release cropland back to the wild, then by far the cheapest way
to do it is improve farming infrastructure and practice in low income
countries, which is where yields lag so far behind the state of the art.

Not a technical problem, a social one.

~~~
pbhjpbhj
Social, or political - giving less technological countries advances shifts
power.

And who in those countries gets the advances? A corporation or a community -
if a community currently grow the own food inefficiently and you take the
growing land, give it to a corporation and produce the same food efficiently
then the people lose income, need to buy their food, and all financial
benefits of the food sale get privatised. The value produced by that land is
moved. We need to be careful not to spread the bad parts of efficient
production.

------
tosh
> yields for wheat grown in indoor vertical farms under optimized growing
> conditions would be several hundred times higher than yields in the field
> due to higher yields, several harvests per year, and vertically stacked
> layers. Wheat grown indoors would use less land than field-grown wheat, be
> independent of climate, reuse most water, exclude pests and diseases, and
> have no nutrient losses to the environment. However, given the high energy
> costs for artificial lighting and capital costs, it is unlikely to be
> economically competitive with current market prices

~~~
yazaddaruvala
However, the study doesn’t seem to include the costs of transportation. I wish
they had looked at the wheat supply chain holistically rather than only cost
per hectare.

Building a close to the city, colocated flour, and/or cereal factory under the
wheat farm, allowing gravity to help build automations would reduce holistic
costs. I wonder if that makes this farming method profitable?

~~~
sacred_numbers
Transportation costs are really not that high. Let's say that the farm is
2000km away from the city. Average freight cost per ton-km via truck is about
12 cents, so an additional $240/ton. Via rail it's about 3 cents, so an
additional $60 per ton. CO2 emissions follow a similar ratio, about 97 grams
per ton-km for trucks and 22 grams for rail, so between 44 and 194 kg CO2 per
ton.

Growing a metric ton of wheat with 100% supplemental light requires
150,000-400,000 kwh. That's $3,000 to $8,000 in electricity costs at 2 cents
per kwh (very cheap) and would require electricity to generate about a gram of
CO2 per kwh at the most to be better in terms of CO2 emissions.

If you have free, non-polluting electricity it would be better to use it to
synthesize fuel for trucks to carry grain from the fields, or to capture CO2
from the air.

~~~
ssorallen
“would be better”

There are other inputs to growing outdoors: fertilizer usage, water usage, and
insecticide/pesticide usage (likely not an exhaustive list). In a controlled
environment like an indoor farm the use of each of those is dramatically less
than in traditional farming. It would be worthwhile to include all of the
inputs of growing food since light and transportation are not the full list.

(disclosure: I work for an indoor, vertical farming company)

~~~
gus_massa
Yes, but does the reduction of the other cost win against the increase of cost
of illumination? Do you have a table with an estimation of the cost in each
scenario?

Some back of the envelope calculations: From [1] the cost of fertilizer is
like $150/acre and from [2] you can get about 7 tons/acre, so it's like
$40/ton. The numbers change a lot from source to source, so let's multiply
that by 2, and we get $40 of fertilizer per ton.

So in the impossible best scenario where the indoor production saves you the
100% of the fertilizer, you save $40 per ton of fertilizer that is much less
that the $3000 per ton of electricity for illumination.

[1] [https://farmdocdaily.illinois.edu/2017/07/fertilizer-
costs-i...](https://farmdocdaily.illinois.edu/2017/07/fertilizer-costs-
in-2017-and-2018.html)

[2] [https://www.seedcorn.com/resources/estimating-corn-silage-
yi...](https://www.seedcorn.com/resources/estimating-corn-silage-yield)

~~~
xyzzyz
Even if you go full renewable fertilizer, and run Haber-Bosch process with
electrolysis-based hydrogen and electricity as energy source (instead of
natural gas which is currently used for both), you’d still increase the price
of fertilizer by a factor of 5 at most, not getting even close to the cost of
artificial illumination.

------
seiferteric
Something I have been thinking about for a few years... How far away are we
from being able to grow seeds on a substrate directly and skip growing the
plant at all? What I envision is a substrate that is able to provide the
nutrients needed for embryo growth, maybe with micro channels or pores. You
could "seed" the substrate with embryonic plant cells, then when they are
done, you just scrape them off. Is that totally crazy?

~~~
h2odragon
[https://en.wikipedia.org/wiki/Micropropagation](https://en.wikipedia.org/wiki/Micropropagation)

like that?

~~~
seiferteric
Not exactly, that's more about propagation of plants, after-which it grows
into a normal plant. I am thinking that we could only grow the desirable part
of the plant, like the seeds in the case of corn or wheat.

------
rasmusei
Some comments have already touched on this, but it is important to realize
just how much electricity we are talking about. The tl;dr is that replacing US
wheat production alone would use five times the current total US electricity
consumption. And that's for wheat, occupying about 10% of US cropland.

See p. 12 of the Supporting Information and you'll find the following: 2026647
kg wheat grown using 798417 MWh electricity means an electricity consumption
of 0.4 MWh/kg wheat. In the US, the annual wheat harvest is 150-200
kg/capita/yr, which in this hypothetical system would use more than 60 MWh
electricity/capita/yr.

For comparison, the US annually uses around 13 MWh electricity/capita.

That is, this hypothetical wheat production in the US would use about five
times the _total_ present day electricity use.

Soybeans and maize together occupy more than three times the wheat area in the
US, so that (very roughly speaking) adds another annual electricity
consumption of ~200 MWh/capita. With just these three major crops, the US
would have to increase its total electricity consumption about 20-fold.

~~~
the8472
So, as usual with all material problems, if we had unlimited free energy we
could solve them.

[https://xkcd.com/1123/](https://xkcd.com/1123/)

------
kickout
[https://thinkingagriculture.io/what-silicon-valley-doesnt-
un...](https://thinkingagriculture.io/what-silicon-valley-doesnt-understand-
about-agriculture/)

Just say no to vertical farming for row crops. Can’t beat the sun (and scale)!

------
tosh
naive question: would it help w/ energy costs to have the vertical farms under
ground and to use mirrors to redirect sunlight (I guess it will still not be
enough and require additional artificial lighting?)

one argument against vertical farming seems to be the high occupancy costs in
larger cities. Why not build them outside of cities and connect them?

[https://en.wikipedia.org/wiki/Vertical_farming#Problems](https://en.wikipedia.org/wiki/Vertical_farming#Problems)

~~~
rtx
Because occupancy cost is very low outside the cities.

~~~
AnimalMuppet
Either I missed something, or your answer doesn't actually address the
question.

Could you explain what you mean a bit further?

~~~
rtx
It's about why don't they move the vertical farms outside the city. Farming on
lands outside population center is cheaper than on vertical farms at the same
locations. This is due to low cost of land and benefits of mechanisation.

Right now we have excess food production.

~~~
AnimalMuppet
I see your point. But if they get the claimed several hundred times the
productivity, then they need several hundred times less land. That land is
still several thousand dollars an acre, even out in the sticks. That's a _lot_
of money that can be saved on the land.

> Right now we have excess food production.

True. If this vertical approach produces wheat for less money, then it will
take over. If not, then it won't... today. There's this whole climate change
thing. People suspect that it's going to harm food production. Can we control
this smaller environment well enough for it to still be productive? Better
than we can control outdoor farms.

------
jsilence
Sorry, but growing grains in vertical farms absolutely does not make sense.
unless you'd have a very very cheap zero emission energy source. which would
have a plethora of other sensible applications.

The single most sane way to change agriculture for the better is to eat much
less beef. hands down. simple as that.

~~~
fsflover
> unless you'd have a very very cheap zero emission energy source

Like nuclear?

~~~
jsilence
too expensive for this application. The article is calculating with 2 ct/kWh
and comes to the conclusion that it is still too expensive.

------
khawkins
A picture of these vertical farms would have gone a long way towards helping
me understand what all would be required to deploy these things. Yet they
decide to use white-space to tell me what the population of the world is and
estimates of it in the future and why farming is important.

------
unchocked
These studies are really interesting to think about for space settlements.

Terrestrially, you're never going to get more efficient use of an acre of
sunlight (~4 MW at noon) than you will with photovoltaics (~75% loss ~= 1 MW
at noon) and conversion to artificial light.

But it could totally work on some future Trantor with flying cars and fusion
engines.

* edit: another poster has dug into the appendix and concluded that you might be able to do about as good w/r/t land use with photovoltaics, presumably due to other factors affecting plant growth.

~~~
trhway
> you're never going to get more efficient use of an acre of sunlight (~4 MW
> at noon) than you will with photovoltaics (~75% loss ~= 1 MW at noon)

green plants don't use the middle, thus they are green, of the spectrum - i.e.
they use only 10-20% of the sunlight. So, very efficient photovoltaics (or
other type of solar powerplant) -> electricity -> only red and violet LEDs may
even beat the Mother Nature in efficiency a bit. Add to that various
optimizations - for example with the LEDs you aren't limited by the Sun
singular position in the sky and can shine light from all the needed angles,
like no more leaves being in the shadow of other leaves, thus increasing the
photosynthesis throughput of a given plant.

~~~
afiori
Some plants (like tomatoes IIRC) even have a better photosynthesis efficiency
when the light comes from below.

------
eadan
The problem with vertical farming is where does the energy come from? An acre
of solar panels is not capable of supplying enough energy to grow an acre of
crops, even with the efficiency gains we've had in photovoltaics and lighting
with wavelengths tuned to crop growth. What's the point in having fields of
solar panels when we could have smaller greenhouses filled with crops? If only
nuclear energy was politically viable in the west we could have vertical
farming and so much more.

~~~
m4rtink
Well, can't easily grow crops on untreated desert ground, but easy to put
solar panels there to power your enclosed vertical farm.

~~~
aalleavitch
Yes, soil, temperature, and weather control are huge, as is the lack of need
for pesticides. Hard to over-state how much controlled environments can
improve yields and crop quality and reduce costs of maintenance (in return for
large initial capital investment).

~~~
afiori
My understanding is that this is how the Netherlands became one of the biggest
food exporters of the EU

------
dawsmik
"have no nutrient losses to the environment." Not Possible, unless you leave
the plant in place. All nutrients come from our environment.

------
nanomonkey
I'm curious if this would be a good use of land in places like the Saharan
desert, semi vertical greenhouses would optimize for water loss and light
usage, and there is plenty of sand for production of the glass walls and
growing medium.

------
gbronner
Someone needs to invent the elevator combine -- existing combines are super
efficient. Not sure how you harvest wheat in a vertical frame efficiently
though. Maybe the frame rotates and you guillotine it all off?

------
mensetmanusman
Would love to peak forward 100 years and see the amazing amount of vertical
farms near city centers and all the converted agricultural land in the U.S.
given back to nature reserves.

------
Havoc
At present I think it makes more sense to focus on high value crops.

Eg I’ll pay a premium for pesticide free, fresh salad from a Urban vertical
farm. Wheat less so

~~~
ssorallen
High value and highly perishable. Wheat can be stored for years, but the shelf
life of your kale/arugula/romaine salad is a matter of days.

------
ArkVark
What about growing genetically-engineered 'nutrient algae' in giant pools, and
processing the resultant biomatter into bars for consumption? A layer of glass
could even be put over the pool to control conditions.

If we're pursuing maximum nutrient and calorie output for minimum fertilizer
and energy input, why look at traditional plants at all?

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aaron695
Has everyone gone insane?

The only thing worth growing in vertical farms is branded "Vertically Farmed"
artisanal products for the rich.

Surely you can see wheat is not great for this.

You still then have to put the world's most expensive wheat through the
artisanal bread making process. How will this be profitable?

~~~
haram_masala
Volume.

~~~
handmodel
I'm honestly curious though how volume would make this work. What is the
square footage of the largest vertical tower you think could be built for
under $1B? And how much would that same land cost you in Nebraska?

------
poma88
What are the costs of this fantasy? How much more expensive per tonne, 10
fold?

------
jmkd
I see corona-disused office blocks in city centres wrapped in mirroring
systems that reflect sunlight throughout each floor to become farmscrapers.

------
novalis78
It’s fascinating how new and cheaper forms of power (Fusion or Molten salt
nuclear reactors looking at you) we unlock another plane of abundance.

