Discussion on:

Flushing toilets could heat future buildings

What's the logic behind requiring all buildings by themselves to produce more energy than they consume or produce only clean water?

It's true that if every building met this constraint then society as a whole would be a lot cleaner. But it's not the only way to meet these goals, nor necessarily the most effective. Let's say your building meets the energy requirement by installing solar cells on one side of the building. Then the owner of the land next to your building wants to build a new building on his land which would cast shadows on the solar cells of the your building, causing it to become a net energy user. Does this mean the new building can't be built? Ridiculous, when other solutions for renewable energy are possible.

It's silly thinking like this that actually makes it harder to solve our environmental problems!

Isn't that a scenario for the Coase Theorem?

I wonder how much energy could be created from the water going down the pipes. I would imagine that a 1,000 ft drop could turn some turbines.