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The Future of Food on Urban Rooftops

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Re: The Future of Food on Urban Rooftops

#2
Conventional wisdom says each person requires ~1 acre (43k sq-ft) to source enough foodstuff for themselves.

With two people per 1k sq-ft apartment... you need ~100-fold improvement over the conventional wisdom to get full 100% sustainability. So let's assume you can magically get 10x gains in "land use" efficiency, and that you can stack those units 10 levels high (piping 1/10 of the 1kW/m^2 solar incidence to each level). But herein lies the rub: Urban density exceeds 2 people per 1k sq-ft of building rooftop area. So 100% rooftop sustainability is probably a no go.

Of course something is better than nothing (is it truly better than rooftop solar?), but it's worth pointing out that it can't be a panacea.

Re: The Future of Food on Urban Rooftops

#3
post #2

Conventional wisdom says each person requires ~1 acre (43k sq-ft) to source enough foodstuff for themselves. With two people per 1k sq-ft apartment... you need ~100-fold improvement over the conventional wisdom to get full 100% sustainability. So let's assume you can magically get 10x gains in "land use" efficiency, and that you can stack those units 10 levels high (piping 1/10 of the 1kW/m^2 solar incidence to each…

From what I recall reading some of the newer indoor hydro systems (plus LED) were getting greater than 20x increases (I think the lettuce/basil warehouse in Japan was getting over 60 heads of lettuce per square foot in comparison to traditional 3 per square foot in standardized farming). Perhaps by combining some of the different newer technologies they'll get the orders of magnitude of differences.

Re: The Future of Food on Urban Rooftops

#5
post #2

Conventional wisdom says each person requires ~1 acre (43k sq-ft) to source enough foodstuff for themselves. With two people per 1k sq-ft apartment... you need ~100-fold improvement over the conventional wisdom to get full 100% sustainability. So let's assume you can magically get 10x gains in "land use" efficiency, and that you can stack those units 10 levels high (piping 1/10 of the 1kW/m^2 solar incidence to each…

Is this 1 acre per person per year?

Re: The Future of Food on Urban Rooftops

#6
post #4

On the opposite end of success we have a rooftop greenhouse in Vancouver being sold on craigslist: http://www.cbc.ca/news/canada/british-columbia/craigslist-va... ( http://vancouver.craigslist.ca/van/bfs/5133023654.html ).

>There is an ongoing lawsuit between the City, EasyPark (managers of the parkade) and Clay Haeber (a former board member of Alterrus and the current owner of the farm) over a deal that would have seen the business taken over by Affinor, a Montreal-based medical marijuana firm.

Yep, definitely Vancouver.

Re: The Future of Food on Urban Rooftops

#7
post #2

Conventional wisdom says each person requires ~1 acre (43k sq-ft) to source enough foodstuff for themselves. With two people per 1k sq-ft apartment... you need ~100-fold improvement over the conventional wisdom to get full 100% sustainability. So let's assume you can magically get 10x gains in "land use" efficiency, and that you can stack those units 10 levels high (piping 1/10 of the 1kW/m^2 solar incidence to each…

Is this 1 acre per person per year?

You don't need a new acre next year, so the units work out for 1 acre/person.

Re: The Future of Food on Urban Rooftops

#8
post #3
post #2

Conventional wisdom says each person requires ~1 acre (43k sq-ft) to source enough foodstuff for themselves. With two people per 1k sq-ft apartment... you need ~100-fold improvement over the conventional wisdom to get full 100% sustainability. So let's assume you can magically get 10x gains in "land use" efficiency, and that you can stack those units 10 levels high (piping 1/10 of the 1kW/m^2 solar incidence to each…

From what I recall reading some of the newer indoor hydro systems (plus LED) were getting greater than 20x increases (I think the lettuce/basil warehouse in Japan was getting over 60 heads of lettuce per square foot in comparison to traditional 3 per square foot in standardized farming). Perhaps by combining some of the different newer technologies they'll get the orders of magnitude of differences.

So why not use these techniques where land is cheap instead of on expensive urban rooftops?

Re: The Future of Food on Urban Rooftops

#9
post #8
post #3

Earlier quoted context omitted.

From what I recall reading some of the newer indoor hydro systems (plus LED) were getting greater than 20x increases (I think the lettuce/basil warehouse in Japan was getting over 60 heads of lettuce per square foot in comparison to traditional 3 per square foot in standardized farming). Perhaps by combining some of the different newer technologies they'll get the orders of magnitude of differences.

So why not use these techniques where land is cheap instead of on expensive urban rooftops?

Because then you're still transporting it to the populated areas?

Re: The Future of Food on Urban Rooftops

#10
post #8
post #3

Earlier quoted context omitted.

From what I recall reading some of the newer indoor hydro systems (plus LED) were getting greater than 20x increases (I think the lettuce/basil warehouse in Japan was getting over 60 heads of lettuce per square foot in comparison to traditional 3 per square foot in standardized farming). Perhaps by combining some of the different newer technologies they'll get the orders of magnitude of differences.

So why not use these techniques where land is cheap instead of on expensive urban rooftops?

Part of the thought was to also reduce transport cost. So if you have effectively the harvest and distribution localized one would reduce footprint in other ways.

That being said I'm not saying "expensive urban rooftops" are where we should be doing this. I was simply suggesting there are other changes afoot that are, for example, increasing yield. Any location will have pros on cons such as locality, cost, infrastructure, space reuse, etc.

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