Wave power excites as next energy source

With fear over nuclear power running high and concerns mounting over global warming, ocean waves have been attracting attention as a source of natural energy.

News photo
Channeling: A navigational buoy with wave-powered lights floats about 1 km offshore from the city of Imizu, Toyama Prefecture. RYOKUSEISHA CORP. / KYODO

Researchers have estimated that ocean waves could produce around the same amount of electricity for Japan as 36 nuclear reactors, but the development costs would be high and there are still many technological challenges before putting waves into practical use alongside solar power.

The government enacted a law in late August to promote renewable energy sources and require power suppliers to purchase electricity produced by other firms and households using renewable energy.

The government did not include tidal power on the list of such energy sources.

It nonetheless has decided to pay as much as ¥7.8 billion for a five-year feasibility experiment on capturing the energy of ocean waves and converting it into electricity, starting this fiscal year.

The move comes amid the struggle with radioactive contamination and electricity shortages stemming from the Fukushima nuclear disaster.

Toyama Prefecture introduced navigational buoys with wave-powered lights about 20 years ago.

Anchored to the sea floor, the four buoys with red and green lights float about 1 km off the city of Imizu to guide ships into the harbor at night.

The lights, manufactured by Tokyo-based Ryokuseisha Corp., a maker of buoys and other marine equipment, have played an important role in guiding large ships in and out of Toyama Shinko port.

Power is produced as air inside the lights is pumped toward their turbines when the buoys rise and fall with the waves, causing the turbines to rotate.

The start of research and development on wave power generation in Japan dates back about a century.

It slowed down after the end of World War II, however, when the nation eventually embraced nuclear energy. Today there are only a few companies, including Ryokuseisha, that have successfully developed products taking advantage of tidal power.

Commercialization of wave power hasn’t fared much better abroad. However, it has drawn renewed attention in recent years amid stepped-up efforts against global warming.

A lot of research has been conducted in Europe in particular, where tidal currents in the North Atlantic and strong westerlies offer a great deal of potential.

Data compiled in 2009 by a team from the International Energy Agency shows that about 20 feasibility experiments were conducted in Britain that year. In Japan, meanwhile, Saga University and a few other research bodies carried out experiments.

In the Orkney Islands in northern Britain and waters around them are a series of test facilities for wave and tidal energy run by the European Marine Energy Center, which began full operations in 2004 in part with financial support from the British government.

The facilities include undersea cables to transmit ashore electricity generated by wave power and energy converters.

If such facilities are built in Japan, “electricity can be delivered to coastal areas after just two years of feasibility testing,” said Takeshi Kinoshita, a University of Tokyo professor and chairman of the Ocean Energy Association-Japan, a group of researchers promoting marine energy sources.

Generating power in waters up to 100 meters deep about 30 km offshore all around Japan would have about the same electricity generation capacity as 36 reactors, according to Kinoshita.

Of the nation’s 54 commercial reactors, only 12 were in operation as of Sept. 1. The March 11 earthquake and tsunami crippled the Fukushima No. 1 plant, and the subsequent crisis led the government to order the Hamaoka nuclear power station in Shizuoka Prefecture to shut down due to fears of another major quake. Other reactors halted for regular maintenance and inspections have not been allowed to restart amid public safety fears.

Researchers say challenges remain for wave power generation, as massive investments would be needed to construct equipment to counter typhoons and salt damage. It would also be necessary to build undersea cables and berthing facilities, and maintain power generators in rough seas, raising the costs of power generation even higher.

Kinoshita stressed, however, that waves represent massive untapped energy.

To develop technologies for generating wave energy at low cost, the government-backed New Energy and Industrial Technology Development Organization will begin the ¥7.8 billion feasibility study this fiscal year, and it will also involve the private sector.

Before the Fukushima nuclear crisis, the cost of producing power at an atomic plant was estimated at ¥10 or less per kwh. The organization will aim to produce wave power at a cost of ¥5 to ¥10 by 2030, according to NEDO officials.

The Japan Times


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