Elite Engineer

Vertical Farms: Ethanol Fuel

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In this hypothetical questions, let's assume the infrastructure and automotive industry is well suited to run on ethanol fuel.

 

Would a vertical farm, off shore much like oil rigs, be the best way to cultivate corn or even switchgrass? Think of a 70-story

building, 3 acres per floor. All water is provided at the source. Crops could be genetically engineered in a way that 

you'd obtain the highest yield, and the genetic modification wouldn't harm people as it wouldn't be consumed. Picture as many vertical

farms as there are oil rigs. Why not in the future, convert the oil rigs into vertical farms?

 

~EE

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Conceptually it seems workable to me.  The drawback is that, if I recall correctly, Ethanol provides about 60% as much energy per gallon as regular gasoline, so this solution would increase carbon dioxide buildup in the atmosphere for the same power delivered to the vehicles.  Seems like this is going in the wrong direction.  I'm not sure of the numbers here, but that's what I would look into.

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Posted (edited)

The daily output of one of those rigs would be 1500 gallons a day or 150 000 gallons in the growing season of a 100 days in length. This is assuming good day conditions and basically using the same resources as present agriculture. Is it worth it? Sugar beet is the highest yielding crop.

Edited by StringJunky

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Posted (edited)

How about other procedure:

Genetically modify microorganisms and/or algae to produce fuel of choice *).

Place them in in the middle of nowhere (e.g. desert) inside of large tanks, artificial lakes, pump to them carbon dioxide (solar panels) and fertilizers.

Filter/gather produced by them fuel.

*) ethanol is miscible with water. Benzene is weakly soluble with water. I think it's better choice, because it will be easier to extract from water.

 

Edited by Sensei

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Well sure, it doesnt have to be corn or switchgrass. If sugar beet has the highest yield then do it. But I believe the whole concept would be worth it. 

2 hours ago, Sensei said:

How about other procedure:

Genetically modify microorganisms and/or algae to produce fuel of choice *).

Place them in in the middle of nowhere (e.g. desert) inside of large tanks, artificial lakes, pump to them carbon dioxide (solar panels) and fertilizers.

Filter/gather produced by them fuel.

*) ethanol is miscible with water. Benzene is weakly soluble with water. I think it's better choice, because it will be easier to extract from water.

 

My issue with this is:

-You're still limited to building in 1 dimension, and in the future, space will be limited. 

-The task of constantly supplying thousands of gallons of water to maintain growth would be ridiculous. If you do manage to get the 

artificial lake built, you're talking about one huge lake. With the vertical farm idea, you could in theory use structure of the old oil rigs.

- An open ocean would get plenty of sunlight for solar energy. 

 

I think the halfway point here is vertical farms in the ocean that grow algae. 

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Posted (edited)
38 minutes ago, Elite Engineer said:

- An open ocean would get plenty of sunlight for solar energy. 

Open ocean's farms of algae was my previous idea. But it also has some issues.

1) weather.

2) you can't use gravity to auto-separate fuel from algae/microorganisms (and they will die if concentration of whatever they produce will be too high).

3) If fuel is miscible with water, ocean would have to be completely separated from farm..

4) you would have to transport them to land, and ferment on land, to convert them to something more usable.

We can imagine GMO algae which have "fruits" filled by some kind of fuel. After squeezing them, fuel is released. Like olive oil extraction.

 

Edited by Sensei

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1 minute ago, Sensei said:

Open ocean's farms of algae was my previous idea. But it also has some issues.

1) weather.

2) you can't use gravity to auto-separate fuel from algae/microorganisms (and they will die if concentration of whatever they produce will be too high).

3) If fuel is miscible with water, ocean would have to be completely separated from farm..

4) you would have to transport them to land, and ferment on land, to convert to something more usable.

We can imagine GMO algae which have "fruits" filled by some kind of fuel. After squeezing them, fuel is released. Like olive oil extraction.

 

There are no hurricanes or savage storms on the equator.

The US Navy can produce fuel from CO2 and H2O in sea water; they say more economically than sending a tanker to ships at sea. I beieve they intend to use nuclear fuel to power the process. It can be done with solar power, though. The economics of algae for fuel hasn't improved much compared to other power technologies.

Floating farms for food may make sense for fish farms now and may make sense some day for other food. However, in the near future less expensive desalination is needed for crops grown on land. .

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43 minutes ago, Elite Engineer said:

-You're still limited to building in 1 dimension, and in the future, space will be limited. 

Lakes and tanks have three dimensions, width, height, depth..

You just have to reach deeper level with light. Vertical farms also use LEDs, R & B, with little G, to deliver light.

 

2 minutes ago, EdEarl said:

However, in the near future less expensive desalination is needed for crops grown on land. .

..as long as they are vertical farms.. They allow control what isotopes of Carbon get to plants (radioactive Carbon C-14 should be filtered out) and later to animal body and human body.. and allow better optimization of land and water..

7 minutes ago, EdEarl said:

I beieve they intend to use nuclear fuel to power the process. It can be done with solar power, though. The economics of algae for fuel hasn't improved much compared to other power technologies.

That's the whole point. Microorganisms/algae don't require external source of power. They use whatever is delivered by the Sun.

 

If you will be using nuclear plants to convert CO2 and H2O to fuel, and then burn in vehicles, why not deliver nuclear plant's energy straight to vehicles since the beginning.. ? ;)

 

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@Sensei

Power to remove oil from algae and transport it.

Only aircraft carriers and submarines are nuclear, for some reason.

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16 minutes ago, EdEarl said:

Only aircraft carriers and submarines are nuclear, for some reason.

The fuel is rather dangerous.

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Posted (edited)

I could see it maybe working. Need to price out lighting costs. Going to be the main one after everything is setup.

OT:

2 hours ago, EdEarl said:

Only aircraft carriers and submarines are nuclear, for some reason.

Was tried in the past. Cruisers, Army Nuclear Power Program. More recently Rusia is looking to dust off the concept(land mobile).

They offer advantages but not right for every situation, IMO. Safety, cost, etc.

 

Edited by Endy0816

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Posted (edited)
11 hours ago, Elite Engineer said:

Think of a 70-story building, 3 acres per floor.

I'm not sure vertical ethanol farming would manage 3 acres per floor. Maximising the area exposed to sunlight would mean limiting the area to that which allows sunlight to penetrate. Where vertical farming makes effective use of sunlight it makes equivalent large areas that are shadowed; you can't pack them too closely or they shade each other. Light will penetrate mostly from the sides rather than above; no light coming from above will reach the floor below the top one. Ultimately no more sunlight is available than with horizontal farming.

Replacing sunlight with artificial lighting would introduce a major energy input in a process intended to maximise energy output - and even if the lighting is high efficiency, plant conversion of light to energy is not - more than 2% of the sunlight converted is considered very good. That may be improvable by selection, breeding and genetic engineering - but enough? Artificial lighting is not so good; it has to use sunlight as it's principle energy source to deliver more energy than it consumes. The innate usefulness of biofuels has been based on the fact that ones like wood just grow, often on agriculturally marginal land, without cultivation and with minimal processing.

I suspect the much higher efficiency of Photovoltaics combined with electrically driven chemistry has greater potential to produce transportable liquid (or gas) fuels. How well they can compete with (still improving) batteries will probably be revealed over the next decade or two.

Edited by Ken Fabian

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14 hours ago, OldChemE said:

Conceptually it seems workable to me.  The drawback is that, if I recall correctly, Ethanol provides about 60% as much energy per gallon as regular gasoline, so this solution would increase carbon dioxide buildup in the atmosphere for the same power delivered to the vehicles.  Seems like this is going in the wrong direction.  I'm not sure of the numbers here, but that's what I would look into.

At concentrations of 10% or less in gasoline, ethanol improves combustion and raises octane, making the up for some of the energy content loss.  Ethanol concentrations above 10% don't make much sense to me. Better to harvest electricity for electric vehicles (or hybrids) directly, since, as Ken Fabian wrote, energy conversion is low for crops.

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On 1/1/2018 at 7:43 PM, OldChemE said:

Conceptually it seems workable to me.  The drawback is that, if I recall correctly, Ethanol provides about 60% as much energy per gallon as regular gasoline, so this solution would increase carbon dioxide buildup in the atmosphere for the same power delivered to the vehicles.  Seems like this is going in the wrong direction.  I'm not sure of the numbers here, but that's what I would look into.

If you are farming where nothing would otherwise farm, with no external energy inputs, the net carbon effect would be 0% after being put to use. If pulling fossil fuels it is 100 %.

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