The Sears Tower, lately unceremoniously renamed the Willis tower, is about to pioneer a kind of crazy-innovative window, one that produces power without obstructing the view or letting in appreciably less sunlight. It's way too complicated to explain in mere words, so hopefully this image will help. If it doesn't, feel free to be a troll in the comments, since that's the designated toilet for whatever sublimated rage you're feeling over your crumbling marriage.
At first the Willis tower will only replace windows on the south side of the 56th floor; eventually, the whole south face of the building could be slathered in glorious high tech energy generating windows, enough to generate 2 MW of power. The windows have the added benefit of keeping out the excess heat energy that plagues glass buildings.
As incredible as these windows sound, they're only a small part of a larger, $350 million initiative to reduce electricity consumption of the entire Willis tower by 80 percent:
There will be changes involving its exterior walls, mechanical systems, lighting, vertical transportation, water supply, hot water, roofs, operations and maintenance. The most visible changes will be noticed on the roofs of the building, which will consist of gardens, solar panels and wind turbines.