Chinese scientists report starch synthesis from carbon dioxide
phys.orgScalable synthesis of food ingredients could be the final agriculture revolution. Picture fields and farms replaced by smaller, dense industrial complexes more akin to an oil refinery. Some of the saved space could be used for solar panels to provide energy for the synthesis process, and the rest rewilded.
And hydrogen would be an important feedstock, so maybe that "hydrogen economy" thing might happen after all.
Assuming naively: A serving is 665 kilocalories, or1/3 RDA, worth of starch, 1 serving needed per day per human, and capture, synthesis, and storage is 100% energy efficient, .86 kcal per watt hour of energy conversion rate, then you need 775 watt hours of energy per serving per day.
Assuming a standard solar panel and conditions, a 1sq meter panel captures about 700 watt hours per day.
I'd guesstimate the creation is less than 10% efficient, meaning you need 10-11 square meters of solar panels per serving produced per day.
Processing plants or fungus or bacteria from bioreactors is orders of magnitude more efficient.
Whoops. Maybe 17%efficient according to the paper. 5 or 6 square meters.
Tricatel factory: https://www.youtube.com/watch?v=5-x9Eidqnw8
from Louis de Funès The Wing or the Thigh/L'aile ou la cuisse (1976)