Japan Hoping for Unlimited Clean Energy With Giant Ocean Turbine

A Japanese company is set to drop an enormous machine into the ocean to generate power that, in theory, is unlimited.

It's a timely proposition, given that a number of countries around the world are facing soaring energy prices and Japan is heavily reliant on importing oil and natural gas from elsewhere. In fact, the country's reliance on fossil fuel power increased between 2010 and 2016 from 81 percent to 89 percent, Japanese government data shows.

In the same period, its nuclear power network took a hit in the wake of the Fukushima disaster, shrinking from 11.2 percent to less than one percent.

Some renewable options, like large wind farms, are not ideal, partly because of Japan's generally mountainous terrain.

Wave
A stock photo shows a giant wave crashing. A Japanese company is aiming to generate tidal energy using giant turbines. RugliG/Getty

This leaves tidal power as one of the few remaining stand-out choices if Japan wants to build a renewable and domestic energy supply.

To harness this tidal power, Japanese engineers at Ishikawajima-Harima Heavy Industries (IHI Corporation) have built a 330-ton tidal power plant called Kairyu. It consists of a 66-foot central cylinder with two more on either side of it which both have 36-foot turbine blades attached to them.

When operational, Kairyu will be attached to the ocean floor by cables to keep it in place. It will then use the force of the water currents around it to turn the turbines which will generate power. This can then be transferred into Japan's national power grid.

The company has been working on the machine for years, and in February this year completed a three-and-a-half-year test off of Japan's southwestern coast, Popular Mechanics reports.

IHI estimates that it could one day be possible to generate roughly 205 gigawatts of electricity from the tides around Japan, which would be about enough to meet all the country's energy needs. But there's a long way to go.

Kairyu, though huge, is capable of generating 100kW of power. This isn't much when compared with the average onshore wind turbine that has a capacity of 2.5 to 3 MW or more than 6 million kWh a year—enough to power 1,500 average European households with electricity, according to the European Wind Energy Association.

Then there are the wider challenges of tidal power. For one thing, it's expensive because of the high upfront costs of plants and maintenance, according to the Massachusetts Institute of Technology's Climate Portal. There's also a lack of an established production market.

Yet some countries, such as Scotland, have established tidal systems in place. For IHI, the hope will be that tidal energy could be a power source with huge potential if it can be effectively tapped.