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Vertical farming does not save space

lowtechmagazine.com

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Re: Vertical farming does not save space

#321

Post by Retric »

tohmasu wrote: post #302
Retric wrote: post #268

Earlier quoted context omitted.

There are actual current contracts that agree to sell solar at under 2c/kWh. Construction of multiple reactors on the same location is very common, constructing a new reactor next to a reactor being decommissioned isn’t. https://en.wikipedia.org/wiki/Crystal_River_Nuclear_Plant https://en.wikipedia.org/wiki/Rancho_Seco_Nuclear_Generating... https://en.wikipedia.org/wiki/Shippingport_Atomic_Power_Stat... https://en.wi…

Please link. I've read about some far future contracts relying heavily on public subsidies but even those were at a higher price. At that price, earnings would (depending largely on geography) be something like 160-400 USD / 1.8m² panel over a 20 year period. This needs to cover panel cost, inverters and electrical infrastructure, installation&decommission, land rent, loss due to some prematurely dead panels, adminis…

Subsides are common for all forms of electricity generation, but LA’s 2019 1.997c/kWh power purchase agreement is hardly the far future. https://www.pv-magazine.com/2019/06/28/los-angeles-seeks-rec...

Anyway to use a specific example Capacity factor 26.6% (average 2015–2018) https://en.wikipedia.org/wiki/Topaz_Solar_Farm.

Bulk panels are $0.29 per W or 290$ per kW. PS-P72-330W https://sunelec.com/

If 1kw is worth 0.01997 $/h * 24 * 0.266 * 365 * 20 = 930$. Of course they don’t instantly break exactly in year 20. They lose efficiency over time so averaging ~90% over 25 years which is ~100% over 22 years. https://sunelec.com/wp/wp-content/uploads/2020/09/P72_outlin...

I can’t find an exact breakdown of costs spent on panels vs interest, instillation, inverters etc. But, at most we are talking about fractions of a cent worth of subsides to hit 2c/kWh.

Re: Vertical farming does not save space

#322

Post by TheCoelacanth »

jobe_br wrote: post #279
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…

Nevermind that land used for energy often isn’t suitable for farming, so … even with the hypothesis, limited as it is, it’s flawed.

Less suitable than empty air 10 feet above the ground?

How is vertical farming powered by solar panels better than building the same artificial growing environment at ground-level and powering it with sunlight?

Re: Vertical farming does not save space

#323

Post by noetic_techy »

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…

I came here to point out nuclear and fusion also. Lets say you can get the energy cost to near zero, the the 200+ euros left per meter sq could be cut down by looking for construction or scaling efficiencies and even the fact that if energy is near zero from nuclear or fusion power, it might end up lowering construction costs if it can be diverted into use in heavy machinery. I'd love to see this same experiment powered by a small Thorium prototype reactor.

Re: Vertical farming does not save space

#324

Post by frankus »

LeifCarrotson wrote: post #134
Nition wrote: post #17

Earlier quoted context omitted.

Say a plant needs 1/10th of actual full sun during the day, could you theoretically remove the electricity step entirely but "just" (putting "just" in quotes because I'm sure it wouldn't be easy) having some sort of fancy mirror setup on a 10 storey building to send 1/10th of the sunlight hitting the roof to each floor?

Close, it's 1/10th of the spectrum not 1/10th of the intensity. The 'fancy mirrors' required would simply be a prism. You'd separate out the red and blue light and aim it at the plants, and send the green and infrared light to solar cells, to be used for running red and blue LEDs. (Or you could use flourescence if you had something that glowed red or blue when exposed to green or IR light). Check out this spectral pl…

Are there materials that fluoresce at a shorter wavelength than what they absorb? I was under the impression that it was a one-way thing (absorb short wavelength and emit longer wavelength).

Re: Vertical farming does not save space

#325

Post by Misdicorl »

notriddle wrote: post #180
Misdicorl wrote: post #31

Earlier quoted context omitted.

Even more to the point- solar panels live quite easily on roofs, deserts, highway medians. Quite a bit tougher to put functioning agriculture in these places!

Green roofs are a thing, though. https://en.wikipedia.org/wiki/Green_roof

A green roof is pretty. It has plenty of upside. It isnt a productive farm which is the appropriate comparison here

Re: Vertical farming does not save space

#326

Post by frankus »

hctaw wrote: post #61
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 an…

What you have to watch out for is displacing housing to build vertical farms. It’s absurdly cheaper and easier to move food for a person into a city than to move that person in and out of the city on a daily basis.

Re: Vertical farming does not save space

#327

Post by shakezula »

perl4ever wrote: post #316
skissane wrote: post #126

Earlier quoted context omitted.

> If we look into the relatively near future, fusion energy is going to account for a rapidly increasing share of energy production by the end of this decade. I really don't think by the end of this decade there will be any commercial fusion production. I'm sure we will be closer but it is still some decades away. ITER proposes to follow up their current research reactor with a successor (DEMO) which they plan to sta…

When I read that timeline, it doesn't sound serious to me. If you're planning to do something in 40 years, then you don't have the faintest clue how to do it now, which means you don't know when you will know how to do it. It could be 5 years or 1,000 or never. You don't know what you don't know.

We have fusion making consistent and significant gains right now.

Re: Vertical farming does not save space

#328

Post by mannerheim »

pfdietz wrote: post #220
mannerheim wrote: post #86

Earlier quoted context omitted.

Most of the carbon costs of providing food comes from the process of growing it, not transporting it. Most of the carbon costs in transportation also come from consumers driving to and from grocery stores. See: https://www.salon.com/2012/06/16/eating_local_hurts_the_plan...

In the US, we use more energy cooking food than we do growing it. Agriculture is only about 1% of total energy demand.

Food has to be prepared in any event. On the other hand, a move to locally produced food to save energy from transportation can be more than cancelled out if the production requires more energy input.

Re: Vertical farming does not save space

#329

Post by jholman »

pfdietz wrote: post #275
tinco wrote: post #267

Earlier quoted context omitted.

It was an honest question. I don't know which specific regulations, I've never built one but I have heard those who did lament the cost and trouble in even obtaining a site. From what I can see fission reactors are doing just fine in France and Belgium. I don't know the specific numbers but the French don't seem worse off economically, despite having the greenest grid on the planet. Fission has a number of disadvanta…

It was a leading question, pretending to claim that regulation was the cause. Nice walkback, though. Nuclear is in a bad state in France. Their recent attempts to build new reactors have gone massively over budget. Existing reactors are aging and it looks like they cannot replace them. Fission has some disadvantages over fusion, but those disadvantages won't make fusion cheaper than fission (the costs of fuel and was…

> It was a leading question, pretending to claim that regulation was the cause. Nice walkback, though.

Not cool.

I mean, when I first read tinco's comment, I thought what you thought. But either reading is plausible.

If you're going to call someone a liar, maybe just don't reply.

Re: Vertical farming does not save space

#330

Post by AngryData »

airza wrote: post #82
tux1968 wrote: post #74

Earlier quoted context omitted.

The other thing to remember is that there is a lot of land that isn't suitable for farming for one reason or another that can be used for solar.

It's such an important point that's the core value proposition of vertical farming. Arable.land is unlikely to keep up with the combination of population growth and climate change. That's the whole point of the exercise! Solving that problem!

Farmland utilization is on the downtrend everywhere except Africa though.
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