Here's an example: Hammarby Sjöstad, a district on the south side of Stockholm, Sweden. From Scientific American:
Every building in the district boasts an array of pneumatic tubes, like larger versions of the ones that whooshed checks from cars to bank tellers back in the day. One tube carries combustible waste to a plant where it is burned to make heat and electricity. Another zips food waste and other biomatter away to be composted and made into fertilizer. Yet another takes recyclables to a sorting facility.\n
Meanwhile, wastewater is taken to a treatment plant, from whence it emerges as biosolids for more compost, biogas for heat and transportation fuel, and pure water to cool a power plant, which also runs on biofuels grown with the biosolids.
If the district authorities meet their goals, the lucky residents of Hammarby Sjöstad will end up using half as much energy as the average Swede. That's not just good for the atmosphere, it's cheaper for the neighborhood.
Image: Hammarby Sjöstad, a Creative Commons Attribution Share-Alike (2.0) image from jimmyroq's photostream