From sensors to rotor blades, wind is in the air as the Wind Power 2009 Conference gets underway at Chicago's McCormick Place. Citizens for a Greener Evanston has hatched a plan to build a wind farm offshore – about four miles out on Lake Michigan. Nathan Kipnis is an Evanston-based architect and co-chair of the group's renewable energy task force, and explains the need for a wind farm.

Music Button: Kronos Quartet, "Nihavent Sirto", from the CD Floodplain, (Nonesuch records)