4 ms·

Sugar cane is very much the exception. Most crop plants (which have over the years been selected for efficiency indirectly) manage 1-2%. No one is suggesting

Sugar cane is very much the exception. Most crop plants (which have over the years been selected for efficiency indirectly) manage 1-2%. No one is suggesting growing sugar cane indoors yet, just purely on the basis of it's height you won't gain much by stacking it. Also you haven't addressed stacking, heat retention or for that matter nighttime light.

Retric 11y ago
The important point was Sugar cane is not better at photosynthesis than other plants. It simply 'wastes' less energy on growth and 'life'. Break even would take 50% efficient solar collectors and 90% efficient lights including transmission and conversion losses. Clearly, we are nowhere near that point. PS: The only reasonable option would be solar collectors that focus on different parts of the spectrum and let light through to the plants under them.
- lhopki01 11y ago
  You don't need 50% efficient solar collectors. That'd be the case if 1 meter squared of plants had 1 meter squared of leaves. Even at full growth there are large gaps and for most of the growing time there are even larger gaps. 1 meter squared of solar panels is always going to be 1 meter squared. Also plants can't use light above 10,000 lux while solar panels will just generate more power. And again how do you stack plants? How do you keep them warm enough? How do you grow them during the night?
  - Retric 11y ago
    Your solar collectors are not operating at night either. Break even means having 10 square miles of solar farm and 1 square mile of dense indoor farming needs to be more efficient than 11 square miles of farming and that extra needs to cover infrastructure costs. You can play with the arrangements of plants in a greenhouse just as easily as a factory. EX: Stacking plants using clear trays and nutrient bath allows for using more light in the same space. Anyway, the reason why this 'works' is crazy subsidies in Japan which actually has quite a bit of farm land, plus a market for ultra premium lettuce for decorative reasons.
    - lhopki01 11y ago
      Where are you getting 10 square miles of solar farm to support 1 square mile of dense indoor farming? Energy can be stored or brought in from other areas during the night. And no you can't stack in a greenhouse for the same reason that there are hardly any plants growing on the jungle floor. This sort of thing is already being done in London and Sweden. It's the level of automation that is making this news. Of course it starts at the high end but eventually all food will be grown like this just because it'll be the most efficient overall. You focus entirely on the efficiency of photosynthesis in plants when there are so many other variables as for why this is a good idea.
      - Retric 11y ago
        Running these for decorative lettuce in a big city is one thing, when farmers use this for corn in Iowa you might have a point. Shipping bulk rice from US to China is cheaper in terms of energy than shipping electricity required to grow that same Rice. PS: Another sanity check. The US has 922 Million Acres of farmland. At 1kw/m * 8h / day that's vastly more than the world total energy usage. You can't even replace that with fusion power as the waste energy would directly produce significant global worming. (4046 sq M / Acre * 8kwh/day = 32 Megawatt hours per Acre * .92 billion = 30,000 Twh per day, world electricity is under 30,000Twh per year. ) https://en.wikipedia.org/wiki/World_energy_consumption#/media/File:World_energy_consumption.svg https://en.wikipedia.org/wiki/World_energy_consumption#/medi...
        lhopki01 11y ago
        Grains will be the last thing to change and that won't be for a very long time. Also you have to take into account increased yields, faster grow times, lower fertiliser, pesticide, herbicide and tractor fuel costs. Your sanity check is way off. Solar panels only get about 22W/m^2 though out the year on average and they're more efficient than plants. Second the maximum plants can use is about 100W/m^2 and that is at maximum midday strength. Now lets take into account varying intensity of sunlight, growing seasons, leaf orientation, gaps between plants and other factors and your energy requirements are much lower. Research is still being done but most plants grow very well with the full red spectrum and 10-20% of the blue spectrum. This vastly reduces the energy required.

Retric 11y ago

The important point was Sugar cane is not better at photosynthesis than other plants. It simply 'wastes' less energy on growth and 'life'. Break even would take 50% efficient solar collectors and 90% efficient lights including transmission and conversion losses. Clearly, we are nowhere near that point. PS: The only reasonable option would be solar collectors that focus on different parts of the spectrum and let light through to the plants under them.

lhopki01 11y ago
You don't need 50% efficient solar collectors. That'd be the case if 1 meter squared of plants had 1 meter squared of leaves. Even at full growth there are large gaps and for most of the growing time there are even larger gaps. 1 meter squared of solar panels is always going to be 1 meter squared. Also plants can't use light above 10,000 lux while solar panels will just generate more power. And again how do you stack plants? How do you keep them warm enough? How do you grow them during the night?
- Retric 11y ago
  Your solar collectors are not operating at night either. Break even means having 10 square miles of solar farm and 1 square mile of dense indoor farming needs to be more efficient than 11 square miles of farming and that extra needs to cover infrastructure costs. You can play with the arrangements of plants in a greenhouse just as easily as a factory. EX: Stacking plants using clear trays and nutrient bath allows for using more light in the same space. Anyway, the reason why this 'works' is crazy subsidies in Japan which actually has quite a bit of farm land, plus a market for ultra premium lettuce for decorative reasons.
  - lhopki01 11y ago
    Where are you getting 10 square miles of solar farm to support 1 square mile of dense indoor farming? Energy can be stored or brought in from other areas during the night. And no you can't stack in a greenhouse for the same reason that there are hardly any plants growing on the jungle floor. This sort of thing is already being done in London and Sweden. It's the level of automation that is making this news. Of course it starts at the high end but eventually all food will be grown like this just because it'll be the most efficient overall. You focus entirely on the efficiency of photosynthesis in plants when there are so many other variables as for why this is a good idea.
    - Retric 11y ago
      Running these for decorative lettuce in a big city is one thing, when farmers use this for corn in Iowa you might have a point. Shipping bulk rice from US to China is cheaper in terms of energy than shipping electricity required to grow that same Rice. PS: Another sanity check. The US has 922 Million Acres of farmland. At 1kw/m * 8h / day that's vastly more than the world total energy usage. You can't even replace that with fusion power as the waste energy would directly produce significant global worming. (4046 sq M / Acre * 8kwh/day = 32 Megawatt hours per Acre * .92 billion = 30,000 Twh per day, world electricity is under 30,000Twh per year. ) https://en.wikipedia.org/wiki/World_energy_consumption#/media/File:World_energy_consumption.svg https://en.wikipedia.org/wiki/World_energy_consumption#/medi...
      - lhopki01 11y ago
        Grains will be the last thing to change and that won't be for a very long time. Also you have to take into account increased yields, faster grow times, lower fertiliser, pesticide, herbicide and tractor fuel costs. Your sanity check is way off. Solar panels only get about 22W/m^2 though out the year on average and they're more efficient than plants. Second the maximum plants can use is about 100W/m^2 and that is at maximum midday strength. Now lets take into account varying intensity of sunlight, growing seasons, leaf orientation, gaps between plants and other factors and your energy requirements are much lower. Research is still being done but most plants grow very well with the full red spectrum and 10-20% of the blue spectrum. This vastly reduces the energy required.