The first farm without farmers

Discussion in 'Intelligence & Machines' started by Plazma Inferno!, Jan 22, 2016.

  1. Plazma Inferno! Ding Ding Ding Ding Administrator

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  3. Edont Knoff Registered Senior Member

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    I feel odd whenever I read about the use of artificial light for growing plants. Many of our methods to produce electric energy are not very efficient, others are not very sutainable, others pollute the environment.

    Even that LEDs are the most efficient sources of light these days, they still use only about 30% of the electricity to produce light, 70% is warmth.

    Let's make an example with an average coal power plant. The good ones have an efficiency of about 40%.

    So 40% of the energy from the coal become electricty. 30% of this electricity becomes light through the LEDs. Overall 12% of the energy of the coal becomes light, even if there is no loss in the transmission, otherwise one will have to reduice this by another 10 or more percent.

    12% light ... 88% percent of the energy of the coal are wasted!

    And this, while sunlight is free.

    I'm all pro vertical farming, but I do not like this sort of waste of resources.

    In my home I grow plants with artificial light too, as a matetr of curioisity, and in parts, alsop research (To see how much I can trick plants in growing in winter which naturally wouldn't, ect.) I have set up solar panels to collect sunlight from the surface of the house where it's of no use anyways and transport the electricity indoors to have light for the plants where sunlight won't reach otherways. But it is wasteful. It's ok as a hobby thing I guess, but it doesn't scale: I need about 10 times the area of solar panels than I can light up with the electricity for the plants.

    That means to light up the mentioned 4,800m² they'd need 48,000m² of solare panels elsewhere.

    So either way, it's not good. It wastes too much fuel if we assume the electrictiy comes from fossil fueld power plants, and it wastes too much area if we assume the electricity comes from solar panels.
     
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  5. sideshowbob Sorry, wrong number. Valued Senior Member

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  7. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    It shows* few jobs are safe from the 4th industrial revolution - probably not yours either. Redistribution of wealth is increasingly essential, but the trend is just the opposite. (62 people now have more wealth than half the world's population does, and that concentration is rapidly increasing.) What can not be sustained will not be. Bernie Sanders as POTUS would give the transition a chance to be non-violent, in US at least.

    On the article its self: Why can't LED light** not be added to natural sun light? How much reduction in fossil fuel for delivery trucks would be possible? (Note the average food item on your table traveled more than 1000 miles to get there in current US food system.) Which has greater economic value: Large urban warehouses with rooftop solar cell electric energy or lettuce? Which is greater capital investment per meter square? How much production gain is possible with a CO2 enhanced atmosphere?

    * It also shows that increasingly inovation (be it growing plants or high speed trains) originates out side of the US; partly because US has a very poor educational system for most.

    ** Plants, like solar cells use specific wave lengths much more efficiently than others - I. e. most of the sunlight falling on plants just makes heat. The band gap of "agricultural solar cells" might be "tuned" to at least double their useful photon efficiency. - I would not sell this idea short, in the long run, but short term, its economics may be mainly the labor cost saving and lower average delivery cost.
     
    Last edited: Jan 23, 2016
  8. Waiter_2001 Registered Senior Member

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    We at least need to KNOW the robots are safe and not poisoning our food if they are going to farm for us.

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  9. Edont Knoff Registered Senior Member

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    Indoor farms use red and blue LEDs, those are the colors most useful to plants. Compared to my naive construction this results in a 30% better use of energy.

    http://news.panasonic.com/global/stories/2015/44449.html

    There you can see the color of light which plants like most.

    I'm surprised that plants on earth are not optimally tuned to the natural white light of the sun ... but likely light has usually been such an abundant resource for plants that they didn't have to optimize their use of light.
     
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  10. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Thanks for the link. From it you can see that growing food via LED lights is an economic success even with labor cost. Read more at:
    http://news.panasonic.com/global/topics/2014/28210.html

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    The indoor agriculture facility currently produces 10 types of vegetables - green and red leafy lettuce, mizuna (potherb mustard), mini red and white radish, rocket lettuce, basil, ooba (mint herb), mitsuba (wild parsley) and baby spinach. Both leafy and root vegetables are cultivated in the controlled soil-based environment with LED lighting. At present, total production capacity is at 3.6 tonnes annually.
     
    Last edited: Jan 25, 2016
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  11. Edont Knoff Registered Senior Member

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    Singapure is a country which has about zero land for farming. They must import almost all vegetables. Therfore it's easier to make profit with vegetables there, than in wide open country like the USA or Russia.

    But yes, these farms show that even with artificial light, it can be economic in the right scenario (which doesn't contradict my point though, that it's wasteful in the energy balance).
     
  12. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Well that is open to question and I bet it is wrong. For example locally produced near major consumers, like several large restaurants all in the same city block, may have less than 3% as much energy used in distribution*, compared to current processes where the typical food item travels about 1000 miles - often from Southern Californian, which produces about 50% of US's vegetables. (We are only speaking about vegetables.)

    Likewise with increased CO2, the growth rate can be (according to top right of the Panasonic Chart in post 7) 2.5 times faster - less light required.

    What fraction of the solar energy falling on the vegetable leaf is converted into chemical energy by plants? I doubt that conversion fraction is even 50% as high as for the electrical energy input to the LEDs with wave length optimized for conversion to chemical energy in the vegetable. As you know / showed in your post / only a small fraction of the solar spectrum is converted into any chemical energy and the photosynthesis with that that is, is a low efficiency process.

    Thus, without specific data, I bet, that in strictly energy efficiency terms, naturally grown in the open air with occasionally total loses (hail storm etc.) the enclosed, LED grown system is more efficient user of energy (illumination & transport energy). Are you sure your POV is not mixing in the fact sunlight is freely available? - Do the ENERGY efficiency ONLY analysis, if you can to show I would lose my bet.

    * Ideally, the "food factory" is on their roofs and distribution is "gravity powered." Also as the "food factory" is bug free, the energy cost of pesticides occurs only for the conventional open air production. Perhaps the restaurant's waiters, who know what is needed for near zero waste, could do the harvesting between meal times, but that has little to do with energy efficiency - just an economic factor.

    BTW, as I recall, the red and blue light are used by the plants at different times of the day. If correct, then the LEDs could be switched on and off as the plants need those lights for still greater efficiency. Something to do with whether their stoma are open or closed, but I forget the details.
     
    Last edited: Jan 25, 2016
  13. Plazma Inferno! Ding Ding Ding Ding Administrator

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  14. Edont Knoff Registered Senior Member

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    No rather the other way round. Sunlight is for free if you have the land. Thus most other means of lighting are what I called "wateful", unless you use solar power, wind or water power, and even for those you need to produce the machinery that transform those energy sources to light, and will have to deal wiutht he remains of the machienry at the end of their lifetime.

    While sunlight is free and we can't use it up like oil or coal, I have troubles to see artificial light not being wasteful on resources (if we talk growing plants). But you are right, we're arguing with different ideas in the background, thus we come to different conclusions.
     
  15. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Ok, I agree that only directly using solar energy, by the plant can have zero waste, but in practice growing food plants in the open air does have waste, much larger than in the production and ultimate disposal or refurbishing of a wind machine after 25 or 30 years. Waste in the form of non-recoverable pesticides, which are not needed in an enclosed (air tight as the atmosphere is enriched with CO2). Also the production of tractors, harvesters, and operation of them with liquid fuel, etc. is wasteful - perhaps more than the production of solar cells or wind machines and has disposal problems too.

    I am agreeing there is waste in all food production systems, just in the growing process and often during harvesting if by fossil fuel powered machines, as is almost always the case in the US's food production system; but argue that refurbishing the bearings in a wind machine after ~25 years is less waste than the application of pesticides 50 times in 25 years is.

    Further more in the conventional food production system, a large part of the food is itself wasted - limited shelf life, and shipping damage, but if the food is grown on the roof tops of large restaurants, and the waiters only harvest what is needed, for the next meals served, that waste is eliminated too. The main energy saving would be in the less than 3% as much of delivery energy required* - perhaps zero energy if delivery is by gravity chute to the kitchen of the restaurant.

    * Don't forget that in the US the average delivery distance food on your table traveled is more than 1000 miles.
     
    Last edited: Jan 27, 2016
  16. Edont Knoff Registered Senior Member

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    Yes. Maybe I used the word "wateful" in a wrong manner, and you are right the production of farming machinery has the same problems as the production of power plants of whatever type.

    I think the important points have been worked out clearly though - there are cases in which growing plants with artificial light is benficial. Close to the customer, fresh, less transport, less use of pestizides and herbizides.

    But also the opposite is true - ion some cases growing plants on open areas, using the sunlight directly can be beneficial, too.

    I am very confident that from now on we'll see both, depending on the situation the one or the other will be preferred and overall both will continue to be used.

    In another forum where I visit, hobby farmers tell about their experiments with artificial light, and some have quite impressive results. For example home grown tomatoes and cucumbers in winter. Energy cost for lighting for a cucumber plant over 3 months, about 25 euros. Expensive cucumbers at the moment, but it's just the beginning, and it's not only big companies experimenting there, but also individuals.
     
  17. Billy T Use Sugar Cane Alcohol car Fuel Valued Senior Member

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    Good. We have come to a common general agreement - our exchange is, I think a model others should follow.
    * Especially if done in huge volume largely for export as both US and Brazil do.
     
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