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). Duckweed captures thus 10W per square meter. 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!
If duckweed gets 10W per meter squared capture - we need 10 sq m  or 1/400 acre. Very promising. The fish there are a trophic chain loss, so if we have another crop that produces at 1% - then 1/400 of an acre is sufficient to feed a vegetarian on first principle calculations - just for the carbohydrate. 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.
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 20 sq meters of land to feed them¡!!!!!!!!!
 
Doomsday? I don't think so.

Revision as of 12:41, 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). Duckweed captures thus 10W per square meter. Tilapia eat duckweed, so that gets energy down to .1% conversion efficiency at conservative estimates.

If duckweed gets 10W per meter squared capture - we need 10 sq m or 1/400 acre. Very promising. The fish there are a trophic chain loss, so if we have another crop that produces at 1% - then 1/400 of an acre is sufficient to feed a vegetarian on first principle calculations - just for the carbohydrate. 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 20 sq meters of land to feed them¡!!!!!!!!!

Doomsday? I don't think so.