The Burj Al-Taqa Energy Tower was designed to utilize 100% renewable energy. If completed as planned, these 68-story towers (in Riyadh, Dubai, and Bahrain) will receive air conditioning from sea water cooled air and power from solar panels and wind turbine on top.
If being built in any other geographic location, I'd say these buildings were a pipe dream. However, given Middle East construction companies' recent propensity to promise outlandish building projects and deliver, I wouldn't be surprised to see at least one of these green skyscrapers sprout up in Dubai. Link [Inhabitat]
But I hope it works... and that other countries can put the same principles into practice!