Offshore windmills weather crisis

Expansion eyed for plant off Ibaraki running at full capacity


A cheap and simply structured wind-power plant proved more resistant to natural disasters than nuclear plants.

The wind plant 50 meters off the coast of Kamisu, Ibaraki Prefecture, survived the massive March 11 tsunami and is now running at full capacity supplying electricity to Tokyo Electric Power Co., which was greatly compromised when the waves crippled the Fukushima No. 1 nuclear plant.

The wind plant owned and operated by Fukui Prefecture-based Mitani Corp., one of Japan’s two offshore wind-power plants, has seven power generators. Each generator is attached to three propeller blades sitting atop a mast that, when turning, transforms wind into electricity.

“All the windmills and transformer stations were safe. Our facilities proved resistant to tsunami,” Mitani Managing Director Yoshitaka Yamamoto said.

Each mast, sunk into the seabed at a depth of 25 meters, stands roughly 70 meters above the water. The March 11 tsunami reached 5 meters, Yamamoto said. Each transformer is located on a jetty dozens of meters away from the masts and is enclosed in fiber-reinforced plastic measuring 8.3 meters x 4.3 meters and 4 meters high, he said.

The machine stayed dry amid the tsunami because the jetty, connected to a coastal road, is 9.6 meters above sea level and the walls and ceiling kept water from splashing onto the machine, he said.

Although clean and relatively cheap, wind power plant output is far below total electricity demand.

Mitani’s wind plants generate 2,000 kw each, thus the company’s total output is just 14,000 kw. That is about 0.04 percent of Tepco’s current capacity after the largest utility’s Fukushima No. 1 and 2 nuclear plants shut down.

Desperate to avoid blackouts, Tepco has asked Mitani Corp. to run its plant at full capacity, Yamamoto said.

Besides Mitani’s, the Setana Municipal Government has a facility off the coast of Setana, Hokkaido Prefecture, with two wind-power generators. However, each generator’s capacity is only 600 kw.

Wind power accounted for less than 1 percent of Japan’s entire electricity supply in 2007, whereas coal accounted for 27.7 percent, natural gas for 25.8 percent, nuclear energy for 23.5 percent, oil for 13.9 percent and hydraulic power for 6.6 percent, according to Tepco and the New Energy and Industrial Technology Development Organization, or NEDO.

Profitability may be a problem with wind power plants. Yamamoto said his company’s plant’s profit is “not so big.”

“The plant does not need strong wind. Normal wind lets the plant produce the maximum 2,000 kw,” he said.

The government is expected to support promotion of wind power generation at sea as it aims to increase such capacity to an ambitious 10 million kw, equivalent to 10 nuclear reactors, by 2020 from 2.19 million kw in the fiscal 2009, as was stipulated in the strategy on marine renewable energy last May.

Japan had 1,683 inland wind power generators in fiscal 2009, according to NEDO. But residents generally don’t welcome them because of noise and sonic waves that can make people feel ill.

Mitani is planning to add eight more generators to the seven already at the windmill offshore farm, Yamamoto said, hoping the Fukushima No. 1 nuclear crisis will boost the public support for the clean energy.

A wind generator system costs about ¥600 million, Yamamoto said. That compares with hundreds of billions yen for a cutting-edge nuclear reactor. “Still, profitability of nuclear plants is much higher, assuming there is no crisis like the ongoing one with the Fukushima No. 1 plant,” he said.

Besides operating a wind plant, Mitani provides computer system services, sells construction materials, industrial machines and oil products and manages restaurants.