
Ask HN: Can a single city house sustainably produce its own food, energy? - elialbert
what tech breakthroughs would that require? assume lots of money.
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jepler
Let's start with caloric requirements. I found
[http://www.waldeneffect.org/blog/Calories_per_acre_for_vario...](http://www.waldeneffect.org/blog/Calories_per_acre_for_various_foods/)
which I'll take at face value. An acre irrigated and planted with potatoes
supplies 17.8 million dietary calories per acre. To get a round number, assume
yearly food needs of 1 million calories (2739 dietarycalories/day, or about
11500kJ). You'll need about 227m2 under cultivation. My house is on a .17 acre
(690m2) lot, so I have room even without worrying about the area covered by
the house itself. (this is an average-to-large size for my American city)

"Irrigation" means lots of water. I found
[http://www.cals.uidaho.edu/edcomm/pdf/bul/bul0789.pdf](http://www.cals.uidaho.edu/edcomm/pdf/bul/bul0789.pdf)
figure 6 showing peak yield at 23 in/year (60cm). Happily, my home town gets
31 inches of rain per year. Collecting and storing it will be a challenge; if
I wanted to store a year's supply it would be around 136000 liters.
Additionally, water is hard to store here over the winter because of below-
freezing temperatures, but you may need to in order to have the water early in
the season when your plants are starting to grow.

So, I'll go with yes to part of the question: on a good year weather-wise with
good technologies, you can grow enough potatoes to fill your caloric
requirements. With somewhat more area you can probably grow more diverse (but
less energy-dense) foods that can meet other dietary needs.

.. the main item I realize this is ignoring is fertilizer, but with excess
electricity you can use the Haber process to generate all the ammonia you
need. So the main external input is solar energy and water. If you needed to
for the purposes of your question, you could add enough technology so that you
could reclaim substantially all of the water, too.

~~~
elialbert
thanks for the cool answer. I wonder if there are future-sludge type foods to
make this easier / more sustainable / more palatable?

