Here’s Chicago’s City Hall, the Green Roof on which, I understand, is not open to the public. I also heard on an NPR's Science Friday Podcast (April 4, 2008) that the city saved $10,000/year in heating and cooling costs by helping to regulate "heat island" roof temperatures which, unchecked, soar to 160F. I like to think about scale. Where is the potential benefit greatest? Vegas, baby, Vegas...
I've begun to do some thinking in the green roof space. This will be the first in a series on the subject. Combined with some simple maps, inserted here, I encourage dialog. Basically, Chicago's City Hall green roof project saves $10,000 in heating/cooling costs per year. IF we do an area comparison, we can project that a 5 acre green roof project (also 1/2 of the area of the total roof space in this example of the Sands Convention and Expo Center, might save $50,000 per year in heating / cooling costs. Water to supply the green roof can be recaptured by in-room toilet tank displacement savings, per my experience with Patagonia, applied to the resorts in the area. Rainwater recapture can be expected to be minimal but very important. During periods of almost ANY rain, my experience in Las Vegas is that there is flooding. This is not surprising considering the high percentage of land that is paved, the fact that it is a desert and so naturally flood-prone, since the ground is not accustomed to absorbing rainfall. Perhaps the insurance companies that cover the properties would be interested in financing the costs to enable green roofs to reduce claims-?
The Venetian alone, with 4,000 suites, could provide well over 1,000 gallons/day for native plants which consume little water. For each resort, custom green roofs can be designed and implemented to reduce energy consumption, facilitate bottom-line savings for property owners, reduce claims against insurance companies, provide tranquil gardens for guests, and help maintain biodiversity by restoring natural habitat for birds.
Here's a lowres photo of a green roof on U of O campus in Eugene, OR, where they host the PIELC