Japan takes leap into offshore wind energy

Wind turbines have become a familiar sight in the blustery port of Choshi on the eastern tip of the Kanto Plain, but this 126-meter-tall machine is different.

Besides being one of the biggest wind turbines in Japan, it stands in the ocean, ready to take advantage of steady marine winds.

Its base firmly planted in the seabed, the giant windmill, ready to start operations early next year, represents a step forward in tapping the offshore wind power market that has already grown sharply abroad.

Experts say marine wind turbines have much more potential than their land-based counterparts in this small mountainous country, but there is still a long way to go before they become a major source of electricity.

Strong demand for zero emission energies have prompted efforts around the world to develop renewable energy, solar and wind in particular. Here, the Fukushima nuclear crisis has made such efforts an imperative.


A new wind turbine stands 3 km off Choshi, Chiba Prefecture, on Monday.

Experts say offshore wind farms are the best bet because seas surrounding Japan offer many more options than land.

“For the long term, marine windmills have the greatest potential,” said Shinichiro Takiguchi, an executive senior researcher at Japan Research Institute Ltd.

And yet Japan’s place in the global offshore wind power market is still minimal.

News photo

A crane and the platform used to construct the turbine will soon be removed.

Its share was a mere 1 percent of the world’s total capacity, which stood at 4 gigawatts as of 2011. The marine windmill industries in Northern Europe have jumped out in front, with Britain boasting 51 percent and Denmark 21 percent, according to the Global Wind Energy Council.

As a first step, the quasi-governmental New Energy and Industrial Technology Development Organization finished building the giant 2.4-megawatt wind turbine about 3 km off the coast of Choshi on Oct. 14.

The foundation is embedded in the seafloor 11.9 meters below the surface. NEDO and Tokyo Electric Power Co. will conduct tests for two years to see how the local weather conditions affect power output.

Other questions that need answering are whether the power plant can survive typhoons and other violent weather, not to mention saltwater corrosion.

They will also gather data on its operations and disseminate the results to the private sector.

“Offshore wind power is important for our energy security,” Sadao Wasaka, the executive director of NEDO, said this week when the wind turbine was unveiled to the media.

Wasaka said Japan’s potential offshore wind power is estimated at 1.5 billion kw, against 300 million kw for land-based wind farms.

But he acknowledged that offshore wind turbines are much costlier than land-based units.

“It is costly,” he said. “Costs for offshore turbines are considered to be double those for land turbines.”

The biggest contributing reason for the higher cost is that they require underwater cables to link with existing power grids on land.

Takiguchi of JRI said it will take longer to develop wind power than solar energy mainly due to the costs.

“There are often no power grids at places that are suited to build wind turbines,” Takiguchi said.

While solar power can be generated literally anywhere under the sun, wind power needs locations with sufficient wind. Such sites are often far from existing power grids, he said.

The costs are even higher for floating wind turbines, which are still in the test stage in Japan, because they need longer undersea cables. Seafloor-embedded windmill posts can extend from the bottom up to about 50 meters to the surface and farther to accommodate the propellors, but suitable offshore shallows are limited.

The construction cost for the Chosi wind turbine alone was ¥3.5 billion, but just 1 km of underwater cable runs ¥100 million, NEDO officials said.

Despite the expense, however, floating windmills have superior potential and the focus in Japan will eventually shift from fixed-bottom turbines, the officials said.

To develop a full system, the central and regional governments will have to build more power grids that can reach future large-scale offshore wind farms or a group of wind power operators will need to share the financial burden to construct this infrastructure.

Despite the difficulties, Wasaka said NEDO is aiming to develop offshore windmill technologies that can be exported.

“We want to prove that our wind turbines can survive in harsh environments in Japan and appeal to overseas markets,” he said.