Tuesday, September 30, 2014

Bullitt Centre - Connecting technologies and 90 percent rule

Another example of connecting technologies - Bullitt Centre in Seattle - has been called the world’s greenest office building.

The 52,000-square-foot building outfitted with cutting-edge environmental technologies, such as insulation and energy-saving heating and cooling systems, aims at meeting the rigorous standards of the Living Building Challenge. It is supposed to be completely powered by the 575 photovoltaic solar panels on the over sized roof. Completed in 2013 (a year behind the schedule), the US$18.5 million, 6-storey building, designed by Miller Hull Partnerships, is built to be “zero-energy”.

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.

Sunday, September 14, 2014

Underwater Energy Storage

Browsing recently through the latest issue of IEEE Spectrum - my favorite nighttime reading  - I came across of one interesting idea - underwater energy storage, developed and currently being deployed in a pilot project by a Canadian company Hydrostor. Having recently considered a pump back hydro storage for one of our clients, we came to a conclusion that the potential and difficult to accurately estimate  environmental impact of a large scale project (it would not be economically viable on a small scale), its high cost and other limitations make such a project hard to justify.
An underwater energy storage on another hand largely mitigates these problems. One version is a flexible underwater balloon, looking not unlike high-flying air balloon, is convenient for small-to-medium size applications, can be deployed temporary and re-deployed with little disturbance to the fauna and environment at large.

An underwater energy storage implemented as permanent installation is more suited for medium-to-large size applications and can actually benefit underwater fauna by providing with the structure to build an ecosystem not unlike the coral reefs.