Inside Japan’s plan to use a strange giant tube to draw “limitless energy” from the sea

A Japanese tech company has developed an underwater machine capable of harnessing enough energy to power most of the country.

Japan is aiming to achieve net-zero greenhouse gas emissions by 2050 – generating electricity from ocean currents could play a role in reaching that goal.

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Japan’s narrow and mountainous landscape dampens the effectiveness of most forms of alternative energy, such as wind turbines and solar panels.

The country is geographically isolated, made up of nearly 7,000 islands, and its power grid is thin and poorly interconnected.

Generating electricity from ocean currents – the practice of using currents in water to turn a turbine – represents an environmentally friendly solution that could benefit Japan’s vast coastal area.

A three-and-a-half-year field test of a prototype sea turbine called “Kairyu” is considered a proof of concept for the renewable energy system.

Kairyu is attached to an anchor that rests on the seabed – the machine can orient itself in three dimensions for optimal energy absorption.

“The floating generator, anchored to the seabed, utilizes the balance between its buoyancy and the drag caused by ocean currents, thereby generating electrical energy while floating at any desired depth,” according to a report by IHI Corporation.

A cable is attached to Kairyu, which runs along the seabed to a power grid.

Science Alert reported that the performance of a single Kairyu machine is dwarfed in comparison to an offshore wind turbine – IHI says they plan to increase Kairyu’s blades from 11 to 40 meters and cultivate a farm of underwater turbines .

According to IHI, Kairyu tested in the Kuroshio Current, a particularly strong ocean current.

They found that the electricity contained enough energy to generate 205 gigawatts, equivalent to Japan’s current total electricity generation.

Japan is one of the most technologically advanced countries in the world, yet has a high rate of CO2 emissions per capita and consumes 2.5% of the world’s coal supply.

Collective post-traumatic stress from the Fukushima meltdown has brought less explored, more creative options like ocean turbines to the table.

Japanese administrators are going big on renewables – the next benchmark in the long-term plan is to get 24% of the country’s electricity from renewables by 2030.