Literally volumes have already been written about the rebuilding of the World Trade Center (here
's one such volume). We're not going to add our two cents to the lengthy discussion of how the "collaboration" between Daniel Libeskind and David Childs has been working (or not). What we will tell you about, of course, are the green aspects of the proposed Freedom Tower, which will be the world's tallest building at the symbolic height of 1,776 feet.* In a cabled truss section starting above the 60th floor, turbines will power 20% of the building's energy needs with wind coming off the Hudson River. It would be the world's first building to incorporate a wind farm.
Normally cities aren't practical for wind turbines, since other high buildings create turbulence. But when you're the world's tallest building, who else is up there messing with you? Skidmore, Owens, and Merrill (Childs's firm) say the turbines (shown at left) will produce electricity 40% of the time. That should cover the base power demand of the building, which means a whole heap of electricity doesn't have to come off the grid. Over 2.6 million kWh each year to be exact, according to Battle McCarthy
, the firm that helped to develop the tower's wind farm. That's enough energy for a thousand homes. The structure surrounding the turbines is designed to focus the wind and increase its speed by 30%. Green energy is freedom in our books. ::Lower Manhattan Development Corporation ::EERE
* That's still shorter than the 1,815 foot CN Tower, not strictly a "building" but good to know for putting smug Americans in their place. In any case, taller buildings are already being planned; no building stays tallest for long.
An exploded view of the vertical wind farm.