Shimizu Corp. has published plans to complete an underwater city, “Ocean spiral,” by 2030 at a cost of 3 trillion yen ($25 billion). The city will consist of a large sphere supported by a spiral tube structure. The sphere will be able to accommodate 5,000 people and have a diameter of about 550 yards.
The city will descend 1.8 to 2.4 miles down to the ocean floor.
Shimizu said that in the face of rising sea levels caused by global warming, underwater cities might become vital.
Construction is estimated to take about five years. A resin concrete tubular structure and the skeleton of the sphere will first be put in place, followed by placement of transparent acrylic panels and glass fiber reinforced plastic and other materials produced by a large-scale 3D printer.
The city will make use of seabed mining techniques and use osmotic desalination for its water supply. Methane gas found in the ocean will be used as the main source of energy. In this way, the planners hope to make the city self-sufficient. Other fields that researchers want to explore with this project are other deep-water construction projects, marine research, exploitation of seabed resources and seabed mining, deep-sea fishing or farming, and even developing a hotel or theme park.
Shimizu has also proposed a concept for an ecological floating city called “green duckweed” and the construction of solar power plants on the moon.