First Principle Land Requirements to Feed a Person: Difference between revisions
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A person uses 100w of energy from food. [http://sustainability.blogs.brynmawr.edu/2012/07/31/understanding-energy-part-1/]. The sun shines 1000W per sq meter, and plants such as duckweed convert 1% (chemical), or about 10x less than PV panels (electric). Tilapia eat duckweed, so that gets energy down to .1% conversion efficiency at conservative estimates. | A person uses 100w of energy from food. [http://sustainability.blogs.brynmawr.edu/2012/07/31/understanding-energy-part-1/]. The sun shines 1000W per sq meter, and plants such as duckweed convert 1% (chemical), or about 10x less than PV panels (electric). Tilapia eat duckweed, so that gets energy down to .1% conversion efficiency at conservative estimates. | ||
So we stand at a factor of 1000 for human energy requirement from that coming in from the sun. So 1000 square meters, or 1/4 acre. Not so promising. The fish there are a trophic chain loss, so if we have another crop that produces at 1% - then 1/40 of an acre is sufficient to feed a vegetarian on first principle calculations. | So we stand at a factor of 1000 for human energy requirement from that coming in from the sun. So 1000 square meters, or 1/4 acre. Not so promising. The fish there are a trophic chain loss, so if we have another crop that produces at 1% - then 1/40 of an acre is sufficient to feed a vegetarian on first principle calculations. That is 1000 square feet! | ||
Now fish are in principle very efficient converters of feed to ody mass - so if that factor of loss is 50% at best, then the pescaterian requires 200 sq meters of land to feed them. | |||
Revision as of 10:36, 30 June 2016
A person uses 100w of energy from food. [1]. The sun shines 1000W per sq meter, and plants such as duckweed convert 1% (chemical), or about 10x less than PV panels (electric). Tilapia eat duckweed, so that gets energy down to .1% conversion efficiency at conservative estimates.
So we stand at a factor of 1000 for human energy requirement from that coming in from the sun. So 1000 square meters, or 1/4 acre. Not so promising. The fish there are a trophic chain loss, so if we have another crop that produces at 1% - then 1/40 of an acre is sufficient to feed a vegetarian on first principle calculations. That is 1000 square feet!
Now fish are in principle very efficient converters of feed to ody mass - so if that factor of loss is 50% at best, then the pescaterian requires 200 sq meters of land to feed them.