Another example of connecting technologies - Bullitt Centre in Seattle - has been called the world’s greenest office building.
To make enough room for 14,000 square feet array of solar panels the roof had to be made projected as much as 20 feet beyond the building's perimeter. According to the designers, the solar array delivers 242 kilowatts of power in total. In the summer, it will produce more electricity than it uses, and in the winter it will produce less. The surplus power will be sold into the Seattle electric grid. The building then draws electricity from the grid in the winter months when production is low. To achieve its “net zero energy” goal, the summer production surplus must meet or exceed the winter production deficit. While strictly speaking it is not a 100% efficiency, this is a way around the 90 percent barrier.