The race to win GE's "Powering Your Home" Ecomagination Challenge , a contest that invites entrants to design the green home of the future, is on. So far, all the entrants are impressive, but one stands out: a proposal for transit tunnels that power cities.
Submitted by Alessandra Rapaccini and Giacomo Sanna, the CitySpeed Turbine  turns transit tunnels into modular turbines that harness wind power from passing vehicles. The potential for energy is impressive--according to the NY/NJ Port Authority, approximately 202,000 cars pass through the Lincoln and Holland Tunnels each day. Combine that with train tunnels, and the device could be a significant energy source.
We aren't entirely sure how the CitySpeed Turbine fits into the "Powering Your Home" theme, but it's still one of the better--and more popular--entries in the contest. Other favorites include the Sunnovations solar hot water system, Clarian plug-in backup power and storage, and the high-performance seasonal cool roof.