A discussion on a prototype “city building” capable of supporting roughly 2,400 full time residents, as well as a large commercial/industrial district.
Enclosed shopping centers are a dying breed. Part of this comes with how easy it is to purchase something from the internet. However it is certainly possible that we can breath new life into these types of businesses by turning them into something completely different: enclosed miniature cities. This may sound like an absurd idea at first, but in the end, it would make perfect sense in regard to resource management and sustainability. Here are some very early ideas of how a prototype building would function and how much it would cost.
- 1,000 units in residential section
- At roughly 2.4 individuals per household, this would result in an estimated 2,400 people living on site full time.
- 115 room hotel
- Figure an average of 2 people per room.
- 112,000 sq ft shopping mall
- One reason shopping malls are dying is that they feel outdated. There’s no life to them. If this is to be successful, those in the mall will have to feel comfortable. Fresh air, sunlight, lots of plants will all have to be integrated into the mall. An outdoor strip with various stalls would be useful as well for people who really don’t want to feel boxed in.
- 56,000 sq ft commercial/light industry (could include education centers as well)
- 1,500 acres of land
- This should include a large amount of wooded land, be relatively flat, and have a lake which is large enough to act as a reservoir. The goal is to ensure that the 1,500 acres is enough to sustain food supply to the roughly 2,400 full time residents. Note that this would amount to a population density of roughly 1,000 per square mile. This may not seem like a lot, but even at such a low population density, the entire United States population would be able to fit into a plot of land a little bit larger than Texas. The entire world population would easily fit inside the United States.
- Handling 2,400 full time residents, 230 guests at a hotel with 24 hour room service, and a large commercial & industrial division would require a lot of water. A person uses roughly 100 gallons of water per day. So that’s already 260,000 gallons per day. But that’s just a small fraction of total water usage considering commercial and industrial ventures use far more water. Assuming that the water “footprint” of the people spending the full day at the mall account for most of the water consumption, and that the total water footprint for an American is about 2,000 gallons per day, you end up with a figure of 5.2 million gallons per day.
- Sewage treatment plant
- The sewage treatment plant would have to be able to process all of the waste water produced on site. We would need a plant that could easily handle the estimated 5.2 million gallons per day. The Brightwater treatment plant in Seattle Washington may be a good model to use. It’s a state of the art plant which integrates well with the environment and captures any unpleasant smell. 
- On site electricity production
- “Clean” energy sources have some of the highest costs associated with them. Nuclear while a great power source would see a lot of political opposition. Therefore a combination of solar and biomass energy production would be utilized. Emissions would have to be limited by sophisticated capturing techniques.
- For electricity, solar is among the most expensive sources and biofuels are the second most expensive. The cost would increase due to added technologies which would reduce emissions by a substantial amount.
- As a very rough estimate, a figure of 424 kilowatt-hours per sq. meter per year for the mall and ten times that for the commercial/industrial components , while a figure of 13,500 kilowatts per year per capita  would be used for residents and a figure 5 times that for guests. Energy demand should never exceed 50% of production capacity. Taking this into account, the total energy demand would be roughly 17 MW. This would require roughly 750 acres if we relied entirely on solar. [3a]
- Assuming that we at least wanted to accommodate all 2,400 full time residents, how much land would it take to feed them all? Estimates about how many people can be fed with one acre of land vary so much that it is nearly impossible to get a handle on an estimate without knowing what method is being used and what types of food are to be produced. Novel food production methods, including integrated hydroponics and aquaculture (fish farm) systems would be useful as it would allow us to produce many different types of food, supporting complete diets and limiting what needs to be “imported.” Assuming 5 people can be fed using an acre of land, it would require roughly 500 acres of land dedicated to food production. This would leave a little bit less than 100 acres for recreation and timber. A food cooperative model would most likely be used for the farm.
- Some people have noted that, with novel technology, far more than five people could be fed with one acre of land. This is true, but I wanted to use a low end figure in the estimate. Also, the highest yields are with a purely vegetarian or even vegan diet and I did not want to exclude dairy and eggs, or even meat from the production model, especially because I do not consider vegan diets sustainable. They actually require an incredibly high diversity of food, which is usually obtained through global food trade and also generally relies on lab produced supplements.