4 ms·

Yeah, just burn terawatts of fossil fuels to generate light for growing your crops instead of using solar energy and natural photosynthesis.

jka 4y ago
I don't know much about the power consumption and efficiency of vertical farm lighting and heating; can you share any references about them? One thing that does occur to me is that artificial lighting wouldn't be limited by the passage of the sun, so crop growth could potentially continue 24 hours a day.
- jaegerpicker 4y ago
  Vertical farming is far less resource intensive, using LEDS powered by solar or wind and gravity flow designs. I posted this in another comment but here is very brief video talking about it. https://www.youtube.com/watch?v=5clOYWsNhhk https://www.youtube.com/watch?v=5clOYWsNhhk I have other resources should you wish and I ton of personal experience. I have 3 Hydroponic systems (1 off the shelf, 2 custom designed by me) and 2 Aquaponics systems. The custom ones took 3 months to recoup the costs of materials vs the cost of produce, though the liquid fertilizer is a cost and input that I don't love. I've switched most of my effort to Aquaponics (Aquaculture - raising fish, which provides a natural fertilizer), I have 1 microsetup growing herbs and microgreens that has been running for 1 year. Only inputs are water and fish food, I clean it 1 once every 3 months since the plants act as a natural filter to clean the water.
- zdragnar 4y ago
  The original comment suggested putting the farm below apartment buildings ("below grade" means underground). It's extremely costly to provide sufficient light to grown plants, as photosynthesis isn't terribly efficient. Natural sunlight is significantly stronger than what people tend to expect. Not only that, but you would need to move massive amounts of air to keep the plants happy, plus the humidity from being underground and all the water they need. Beyond that, you need to go quite a bit underground to feed a sufficient number of people, which isn't always feasible depending on the type of soil and water table, etc Final note, most plants do better not getting 24 hours of light. They can only grow just so fast and need to photosynthesize just so much. That's a lot of work (meaning higher prices for people who need to eat) for very little gain.
  - jaegerpicker 4y ago
    Below ground has trade offs, it's easier to use gravity flow designs but you lose all natural sunlight. Most of the time rain catchment systems on roof top vertical farms or free standing green houses are easier to design. There are already a bunch of vertical farms in commercial operation. The Netherlands in particular is leading the science here but in the US a number of farms exist. Vertical farming uses around 90% less water and solar/wind/hydro power for LED's is extremely doable. You are wholly incorrect about the amount of work required and amount of resources. It does take smart design to work however.
    - crummy 4y ago
      What's the efficiency loss for light>solar panel>LED>plants vs light>plants?
      - jaegerpicker 4y ago
        Wrong question to ask, PPFD's is the correct measure. It's not a direct energy comparison. Photosynthesis is a chemical reaction of Chlorophyll reacting to certain but not all light wavelength's (Red and Blue being the major ones) plus the distance from the light source. The amount of watts the the sun generates is NOT what grows plants. LED's can produce the same light wavelength's but much closer and with no obstructions. The question isn't about LED's power generation, it's how much power does it take for an LED to cover an area. Obviously a LED can't compare to pure Solar efficiency on a watt by watt basis but it doesn't need to.
      - imtringued 4y ago
        jaegerpicker is really uncooperative, even with numbers that should be easy to debunk he is struggling and trying to change the topic to stop you from thinking critically. https://sustainabledish.com/vertical-farms-thermodynamic-nonsense/ https://sustainabledish.com/vertical-farms-thermodynamic-non... "It turns out it would take about 4.5 acres of solar cells for every one acre of plant growth space" well that implies that the 100x efficiency factor has actually been met for lettuce but jaegerpicker didn't seem too keen on telling you. The obvious problem though is that solar panels are only 20% efficient hence roughly 5 acres of solar per 1 acre of vertical farming grow space.
jaegerpicker 4y ago
This is completely misinformed, there are tons of vertical Hydroponic and aquaponic farms already in production that are thriving at much lower resource costs. Solar panels powering LED's and gravity flow water make a massive difference. For example: One is being built minutes from my house https://verticalharvestfarms.com/locations/westbrook-maine/ https://verticalharvestfarms.com/locations/westbrook-maine/ Also The Netherlands are leading the world at this type of farming, here is a short video about it https://www.youtube.com/watch?v=5clOYWsNhhk https://www.youtube.com/watch?v=5clOYWsNhhk
- chroem- 4y ago
  US farmland occupies 895 million acres (3.6M km^2) [1]. Average solar irradiance on most US farmland is about 200 W/m^2 [2]. By being generous and assuming vertical farming is 100x more efficient than natural photosynthesis, the energy requirements come out to 7.2 terawatts of generating capacity. In contrast, the US currently has 1.1 terawatts of generating capacity. [3] Vertical farming isn't just uneconomical: it's completely absurd. [1] https://www.statista.com/statistics/196104/total-area-of-land-in-farms-in-the-us-since-2000/ https://www.statista.com/statistics/196104/total-area-of-lan... [2] https://en.wikipedia.org/wiki/Solar_irradiance https://en.wikipedia.org/wiki/Solar_irradiance [3] https://www.eia.gov/energyexplained/electricity/electricity-in-the-us-generation-capacity-and-sales.php https://www.eia.gov/energyexplained/electricity/electricity-...
  - mensetmanusman 4y ago
    Thanks for doing the numbers, it’s interesting that in 50 years people are predicting annual TW installs of global solar capacity. So maybe a technology for the future if storage and distribution gets solved.
  - jaegerpicker 4y ago
    Except none of that matters, Solar Irradiance has very little to do with actual photosynthesis. You are measuring Watt's as a pure energy source, that's useless in this case. Photosynthetic photon flux density (PPFD's) are what's important, that's the amount of light wavelengths that the plant needs to absorb to power photosynthesis. Here is a definition from another source, I'll post the link at the bottom: PPFD is a measure of photosynthetic active radiation, PAR for short. PAR is not a measure of anything itself but is more of a description. PAR light is all the visible wavelengths of light which cause photosynthesis, found within the 400-700 nanometer range. PPFD is a ‘spot’ measurement that tells you how many photons from the PAR range hit a specific area of your canopy over time. It is expressed as micro moles per square meter per second (μmol/m2/s). For this reason, PPFD is the most accurate measure of light power. First, unlike other measures, it considers the entire spectrum of light that plants see. PPFD also takes into account the amount of light that will actually reach the plant instead of focusing only on the point of origin. A light source can be very bright and powerful, but if it is too away from the plant, or obstructed in some way, the plant won’t be getting all the light it needs for photosynthesis. PPFD controls for this kind of inaccuracy. With LED's you can place the plants much closer to the light source and control the color spectrum along with the obstructions 24/7. It allows you to grow indoors at an extremely efficient rate. Your formula has almost nothing to do with indoor farming. https://www.freightfarms.com/blog/indoor-grow-lights#:~:text=LEDs%20(light%2Demitting%20diodes),same%20consistent%20and%20directional%20light https://www.freightfarms.com/blog/indoor-grow-lights#:~:text.... Here are some additional sources: https://archipel.uqam.ca/1619/1/1998_025_Gendron.pdf https://archipel.uqam.ca/1619/1/1998_025_Gendron.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1066711/pdf/plntphys00572-0025.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1066711/pdf/pln... https://www.researchgate.net/profile/Paul_Hanson7/publication/283601390_An_optimal_sampling_strategy_for_determining_CO2_exchange_rate_as_a_function_of_photosynthetic_photon_flux_density/links/566ae06608aea0892c4baafb/An-optimal-sampling-strategy-for-determining-CO2-exchange-rate-as-a-function-of-photosynthetic-photon-flux-density.pdf https://www.researchgate.net/profile/Paul_Hanson7/publicatio... https://www.horti-growlight.com/en-gb/par-ppf-ypf-ppfd-dli#:~:text=The%20Photosynthetic%20Photon%20Flux%20Density,a%20given%20surface%20each%20second https://www.horti-growlight.com/en-gb/par-ppf-ypf-ppfd-dli#:.... https://www.sciencedirect.com/topics/medicine-and-dentistry/photosynthetic-photon-flux-density https://www.sciencedirect.com/topics/medicine-and-dentistry/... Quick summary: PPFD measures the amount of light wavelengths that the plant captures that kicks off the chemical reaction of Chlorophyll. Red and Blue lights are the vast majority of wavelengths that interact with Chlorophyll. That's a major reason why the solar irradiance measure of pure Wattage is irrelevant.

jka 4y ago

I don't know much about the power consumption and efficiency of vertical farm lighting and heating; can you share any references about them? One thing that does occur to me is that artificial lighting wouldn't be limited by the passage of the sun, so crop growth could potentially continue 24 hours a day.

jaegerpicker 4y ago
Vertical farming is far less resource intensive, using LEDS powered by solar or wind and gravity flow designs. I posted this in another comment but here is very brief video talking about it. https://www.youtube.com/watch?v=5clOYWsNhhk https://www.youtube.com/watch?v=5clOYWsNhhk I have other resources should you wish and I ton of personal experience. I have 3 Hydroponic systems (1 off the shelf, 2 custom designed by me) and 2 Aquaponics systems. The custom ones took 3 months to recoup the costs of materials vs the cost of produce, though the liquid fertilizer is a cost and input that I don't love. I've switched most of my effort to Aquaponics (Aquaculture - raising fish, which provides a natural fertilizer), I have 1 microsetup growing herbs and microgreens that has been running for 1 year. Only inputs are water and fish food, I clean it 1 once every 3 months since the plants act as a natural filter to clean the water.
zdragnar 4y ago
The original comment suggested putting the farm below apartment buildings ("below grade" means underground). It's extremely costly to provide sufficient light to grown plants, as photosynthesis isn't terribly efficient. Natural sunlight is significantly stronger than what people tend to expect. Not only that, but you would need to move massive amounts of air to keep the plants happy, plus the humidity from being underground and all the water they need. Beyond that, you need to go quite a bit underground to feed a sufficient number of people, which isn't always feasible depending on the type of soil and water table, etc Final note, most plants do better not getting 24 hours of light. They can only grow just so fast and need to photosynthesize just so much. That's a lot of work (meaning higher prices for people who need to eat) for very little gain.
- jaegerpicker 4y ago
  Below ground has trade offs, it's easier to use gravity flow designs but you lose all natural sunlight. Most of the time rain catchment systems on roof top vertical farms or free standing green houses are easier to design. There are already a bunch of vertical farms in commercial operation. The Netherlands in particular is leading the science here but in the US a number of farms exist. Vertical farming uses around 90% less water and solar/wind/hydro power for LED's is extremely doable. You are wholly incorrect about the amount of work required and amount of resources. It does take smart design to work however.
  - crummy 4y ago
    What's the efficiency loss for light>solar panel>LED>plants vs light>plants?
    - jaegerpicker 4y ago
      Wrong question to ask, PPFD's is the correct measure. It's not a direct energy comparison. Photosynthesis is a chemical reaction of Chlorophyll reacting to certain but not all light wavelength's (Red and Blue being the major ones) plus the distance from the light source. The amount of watts the the sun generates is NOT what grows plants. LED's can produce the same light wavelength's but much closer and with no obstructions. The question isn't about LED's power generation, it's how much power does it take for an LED to cover an area. Obviously a LED can't compare to pure Solar efficiency on a watt by watt basis but it doesn't need to.
    - imtringued 4y ago
      jaegerpicker is really uncooperative, even with numbers that should be easy to debunk he is struggling and trying to change the topic to stop you from thinking critically. https://sustainabledish.com/vertical-farms-thermodynamic-nonsense/ https://sustainabledish.com/vertical-farms-thermodynamic-non... "It turns out it would take about 4.5 acres of solar cells for every one acre of plant growth space" well that implies that the 100x efficiency factor has actually been met for lettuce but jaegerpicker didn't seem too keen on telling you. The obvious problem though is that solar panels are only 20% efficient hence roughly 5 acres of solar per 1 acre of vertical farming grow space.

jaegerpicker 4y ago

This is completely misinformed, there are tons of vertical Hydroponic and aquaponic farms already in production that are thriving at much lower resource costs. Solar panels powering LED's and gravity flow water make a massive difference. For example: One is being built minutes from my house https://verticalharvestfarms.com/locations/westbrook-maine/ https://verticalharvestfarms.com/locations/westbrook-maine/ Also The Netherlands are leading the world at this type of farming, here is a short video about it https://www.youtube.com/watch?v=5clOYWsNhhk https://www.youtube.com/watch?v=5clOYWsNhhk

chroem- 4y ago
US farmland occupies 895 million acres (3.6M km^2) [1]. Average solar irradiance on most US farmland is about 200 W/m^2 [2]. By being generous and assuming vertical farming is 100x more efficient than natural photosynthesis, the energy requirements come out to 7.2 terawatts of generating capacity. In contrast, the US currently has 1.1 terawatts of generating capacity. [3] Vertical farming isn't just uneconomical: it's completely absurd. [1] https://www.statista.com/statistics/196104/total-area-of-land-in-farms-in-the-us-since-2000/ https://www.statista.com/statistics/196104/total-area-of-lan... [2] https://en.wikipedia.org/wiki/Solar_irradiance https://en.wikipedia.org/wiki/Solar_irradiance [3] https://www.eia.gov/energyexplained/electricity/electricity-in-the-us-generation-capacity-and-sales.php https://www.eia.gov/energyexplained/electricity/electricity-...
- mensetmanusman 4y ago
  Thanks for doing the numbers, it’s interesting that in 50 years people are predicting annual TW installs of global solar capacity. So maybe a technology for the future if storage and distribution gets solved.
- jaegerpicker 4y ago
  Except none of that matters, Solar Irradiance has very little to do with actual photosynthesis. You are measuring Watt's as a pure energy source, that's useless in this case. Photosynthetic photon flux density (PPFD's) are what's important, that's the amount of light wavelengths that the plant needs to absorb to power photosynthesis. Here is a definition from another source, I'll post the link at the bottom: PPFD is a measure of photosynthetic active radiation, PAR for short. PAR is not a measure of anything itself but is more of a description. PAR light is all the visible wavelengths of light which cause photosynthesis, found within the 400-700 nanometer range. PPFD is a ‘spot’ measurement that tells you how many photons from the PAR range hit a specific area of your canopy over time. It is expressed as micro moles per square meter per second (μmol/m2/s). For this reason, PPFD is the most accurate measure of light power. First, unlike other measures, it considers the entire spectrum of light that plants see. PPFD also takes into account the amount of light that will actually reach the plant instead of focusing only on the point of origin. A light source can be very bright and powerful, but if it is too away from the plant, or obstructed in some way, the plant won’t be getting all the light it needs for photosynthesis. PPFD controls for this kind of inaccuracy. With LED's you can place the plants much closer to the light source and control the color spectrum along with the obstructions 24/7. It allows you to grow indoors at an extremely efficient rate. Your formula has almost nothing to do with indoor farming. https://www.freightfarms.com/blog/indoor-grow-lights#:~:text=LEDs%20(light%2Demitting%20diodes),same%20consistent%20and%20directional%20light https://www.freightfarms.com/blog/indoor-grow-lights#:~:text.... Here are some additional sources: https://archipel.uqam.ca/1619/1/1998_025_Gendron.pdf https://archipel.uqam.ca/1619/1/1998_025_Gendron.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1066711/pdf/plntphys00572-0025.pdf https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1066711/pdf/pln... https://www.researchgate.net/profile/Paul_Hanson7/publication/283601390_An_optimal_sampling_strategy_for_determining_CO2_exchange_rate_as_a_function_of_photosynthetic_photon_flux_density/links/566ae06608aea0892c4baafb/An-optimal-sampling-strategy-for-determining-CO2-exchange-rate-as-a-function-of-photosynthetic-photon-flux-density.pdf https://www.researchgate.net/profile/Paul_Hanson7/publicatio... https://www.horti-growlight.com/en-gb/par-ppf-ypf-ppfd-dli#:~:text=The%20Photosynthetic%20Photon%20Flux%20Density,a%20given%20surface%20each%20second https://www.horti-growlight.com/en-gb/par-ppf-ypf-ppfd-dli#:.... https://www.sciencedirect.com/topics/medicine-and-dentistry/photosynthetic-photon-flux-density https://www.sciencedirect.com/topics/medicine-and-dentistry/... Quick summary: PPFD measures the amount of light wavelengths that the plant captures that kicks off the chemical reaction of Chlorophyll. Red and Blue lights are the vast majority of wavelengths that interact with Chlorophyll. That's a major reason why the solar irradiance measure of pure Wattage is irrelevant.