Japan-based globally renowned construction firm Shimizu Corporation introduces its dream mega-project concept—the Ocean Spiral. Described as a futuristic underwater city, the proposed construction project has been positioned as a viable solution for addressing pressing social, environmental, and economic problems.
Deep sea is the final frontier of earth according to Shimizu Corporation. Setting aside all of the established conventions relating to land development efficiency, the construction firm argues that true sustainability lies within the untapped ocean resources—including near limitless supply of food, energy, water, and minerals.
The Japanese construction firm has positioned Ocean Spiral as an engineering and architectural innovation that centres on deep sea development. Constructing this futuristic underwater city will require vertical linking of air, sea surface, deep sea, and sea floor. Thereby, composed specifically of three sections, Ocean Spiral will feature a true sustainable, self-sufficient environment.
Based on the concept, residential and commercial activities will be housed in the first section of the underwater city, or the so-called Blue Garden, capable of accommodating as many as 5,000 people.
According to the literature published by Shimizu Corporation, the Blue Garden will be a sphere measuring 500 meters in diameter that will float in the deep sea like a space ship—or just below the surface. The firm further asserts that such underwater dwelling place will be safer and more comfortable than land-based ones because it will be unaffected by typhoons and earthquakes, have higher concentration of oxygen, and have minimal temperature changes.
A nine-mile spiral structure called the Infra Spiral will connect the Blue Garden to the seabed. This will be the second section of Ocean Spiral. While essentially uninhabited, the structure will have varying features.
Shimizu Corporation envisions the Infra Spiral as a section capable of power generation by converting ocean thermal energy into electricity. It will also be an appropriate section to house aquaculture for managing food supply, water pressure-driven desalination process for fresh water supply, and a transportation highway for submersible probes.
At the bottom of the entire underwater structural complex is the third section. Otherwise known as the Earth Factory, this section will house so-called deep sea industries.
The construction firm proposes two general industrial activities within the Earth Factory. The first one will be another power generation facility that will use microorganisms to convert carbon dioxide into methane. The second activity will involve the extraction and development of resources or minerals found in sea floors.
While the Ocean Spiral seems a concept stretched beyond reality and current technological capacity, Shimizu Corporation argues that the underwater city could be ready by 2030. Initial investment would only cost at about USD 14 billion. As the project expands, moreover, additional costs will be significantly lesser.
Of course, thus underwater city concept from Japan needs to resolve technological challenges. The construction firm suggests that in order to withstand water pressure, the underwater structures of the Ocean Spiral should be spherically designed. High-strength resin concrete and rustproof resin bars for reinforcement are also materials deemed suitable for the concept.
Maintaining consistent temperature is also possible by natural convection, particularly by using temperature differential between the sea water and air to ensure the natural convection with comfortable and cool air. Air conditioning is possible by using chilled deep sea water. Heating, on the other hand, is achievable by using the insulation effects of 3-meter thick acrylic plates.