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Left conveniently not discussed in the article. Based on the drawing in the article, it looks like they use no natural lighting at all. While clearly crop depe
by ddeck 10y ago
Left conveniently not discussed in the article. Based on the drawing in the article, it looks like they use no natural lighting at all.
While clearly crop dependent, even in a glass building:
"The environmental writer George Monbiot calculated that the cost of providing enough supplementary light to grow the grain for a single loaf would be about $15" [1]
A quick search reveals that typical crop photosynthetic efficiency is around 1-2% [2], and I'm guessing that's likely calculated based on the light that falls directly on the leaf.
The sun delivers >1 kW per square meter in the middle of the day. That's a whole lot of power to replace, even accounting for savings through focusing on the most important wavelengths.
[1] https://en.wikipedia.org/wiki/Vertical_farming#Energy_use https://en.wikipedia.org/wiki/Vertical_farming#Energy_use
[2] https://en.wikipedia.org/wiki/Photosynthetic_efficiency https://en.wikipedia.org/wiki/Photosynthetic_efficiency
- fencepost 10y agoThere's also a note at the very very bottom of the article that "it seems that the energy issue might be reduced by the introduction of a new generation of LED grow lights which reduce the energy required by just providing the plants with the part of the radiation spectrum that they require for growth." It's not clear whether this is from Monbiot or the person who provided the numbers, but either way I invite you to consider the changes in quality, availability and pricing for standard LED bulbs as replacements for incandescent bulbs in the six years since that article was published.