The cities would use a number of technologies to make a carbon negative system. The designers say the compact form of the city alone would allow a 40 percent reduction of CO2 through more efficient transport and distribution, while energy conservation through increased thermal insulation, facility efficiency and next-generation technologies would provide a further 30 percent reduction. The use of solar power provided by space satellites, ocean thermal energy conversion and wind and wave technologies would provide an additional 30 percent reduction. The ocean would also be used for carbon sequestration.
The Green Float concept would also produce zero waste by recycling resources and converting waste into energy. It would even help clean up the oceans by collecting any passing “garbage islands” for use as an energy resource.
Location, location, location
The islands would be located at the equator as it isn’t prone to typhoons and the climate is stable. However, in the event of large waves, strong elastic membranes would be attached to the lagoons around the outer circumference of the cells, with the shallows above the membranes standing 10m (32.8 ft) above sea level. The water pressure difference between the lagoons and the ocean would limit the movement of the membranes and buffer the force of the open sea waves. Additionally, 20-30m (66-98 ft) high seawalls would be constructed to handle a worst-case scenario.
The Green Float concept was on display at the recent Innovation Japan University Exhibition 2010 where DigInfo TV was told that the Green Float cities wouldn’t be fixed in place but would literally float slowly on the ocean currents. Given much of the technology included in the concept doesn’t exist yet, Shimizu, as part of a three-way agreement with the Super Collaborative Graduate School, and Nomura Securities, will initially concentrate on nurturing R&D projects on the technologies required for such a project. However, the company’s hopes of turning it into a reality by 2025 may be a little ambitious.
But ambition isn’t something that seems to be lacking at Shimizu. The company also proposes encircling the moon in a belt of solar collectors that would collect solar energy and transmit it to Earth using microwave and laser transmission technologies. You definitely couldn’t accuse this organization of thinking small.