In general, renovation is "greener" than new construction. The folks over at Jetson Green have published a list of ten reason sprawl isn't green. I don't agree that all of these reasons should be placed in the "anti-green" category - some of them refer specifically to social problems more than ecological consequences of sprawl.

A glimpse of the list:

1. Sprawl development contributes to a loss of support for public facilities and public amenities.
2. Sprawl undermines effective maintenance of existing infrastructure.
4. Sprawl consumes more resources than other development patterns.
8. Sprawl results in the permanent alteration and destruction of habitats.
10. Sprawl offers the promise of choice while only delivering more of the same.

Judging by the attendance at Des Moines Rehabbers Club meetings, people who are dedicated to renovation as an idea seem to be more heavily concentrated in cities and rural areas than suburbs. In general, new suburban greenfield construction - no matter how green each building may be individually - is inherently not a sustainable typology. The embodied energy required to provide new infrastructure and building materials, increased transportation energy, and the increased energy required to maintain and serve the new buildings eclipses any green coating on individual structures.

Most suburban construction makes just the faintest nod to sustainability - probably because most people would see right through it.

I think as gas prices continue to rise, the general population will begin to rediscover value in mixed-use neighborhoods where jobs, entertainment, dining, and homes are located in interconnected, pedestrian-friendly neighborhoods. Segregated zoning, feeder road infrastructure, and big box/strip mall typologies are on the way out.