The regenerative "re-green" movement that's been building in NYC is beginning to take hold in Chicago. This make sense because large, tall structures are a huge investment that would cost tremendous amounts of money to tear down and rebuild, as well as the environmental cost of recycling the materal and the inevitable landfill waste that results. This financial and environmental payback is now becoming apparent to business and industry, especially since the return on investment in future savings and lower energy and water consumption is now valid and quantifiable. Scale matters!
For example, Chicago-based Adrian Smith + Gordon Gill Architecture has the commission to design a $350 million retrofit of the old Sears Tower, now re-named Willis Tower after its new owners. The five-year project will reduce the tower's electricity use by 80 percent and reduce water use by 40 percent, saving 24 million gallons of water annually.
More details on Smith + Gordon Gill clean technology tower methodology are here:"Building on the concept of biomimicry, Clean Technology Tower uses advanced sustainability systems and strategies to foster a symbiotic relationship with its environment. Sited and formed to harness natural forces, the tower refines conventional methods of capturing those forces to increase efficiency."
The retrofit strategy is being globally implemented in other cities now, as this approach takes hold and uses energy savings to pay for the increasing costs to use power and water, as well as reducing greenhouse gasses.