Japan plays the long game with floating technology

JAPAN: The solitary wind turbine floating in the Pacific Ocean, 20 kilometres from Japan's eastern coast, has become something of a poster boy for the wind industry.

Territorial… Japan’s fishing industry has been a powerful offshore wind opponent (pic:Shirokaan)
Territorial… Japan’s fishing industry has been a powerful offshore wind opponent (pic:Shirokaan)

It stands in the shadow of the Fukushima nuclear power plant that failed catastrophically on 11 March 2011 after being struck by a tsunami. Nearly three years on and Fukushima remains the dark centre of a 32-kilometre evacuation zone, its teams still struggling to prevent contaminated water leaking into the sea.

Radiation at the plant's boundaries has reached eight times government safety guidelines. Fish caught close to shore are showing 124 times the level of radioactive cesium that would make them safe to eat. The clean-up and full decommissioning process at Fukushima will run into decades rather than years, and at huge cost. In Japan they call it the disaster that never ends.

The 2MW floating turbine in the Pacific paints a different picture of the future of energy generation in Japan. Its output is, of course, minuscule compared to the 4.4GW of the nuclear plant, but since 11 November 2013 it has been quietly and cleanly providing electricity to the region. The Fukushima project is still at the infant stage, but wind-industry supporters believe it could grow to become the world's first utility-scale offshore wind farm on floating foundations or, failing that, pioneer the techniques and technology that will allow others to generate wind power in deep waters.

Wind power currently contributes less than 1% of Japan's total power capacity, with just 2.6GW installed, virtually all of it onshore. According to Maine International Consulting, offshore wind capacity stands at only 45.6MW spread over 24 turbines at five locations.

Deep water conundrum

Japan's historic reluctance to develop offshore wind can be attributed to three main factors. First, 80% of its offshore resources are in depths greater than 100 metres, far beyond the reach of the conventional fixed-bottom foundations that support the offshore projects on northern Europe's continental shelf. Second, the climate and conditions - typhoons and tsunamis - present formidable challenges to installation and upkeep of wind turbines. Third, Japan's powerful maritime logistics and fishing industries have strongly opposed sharing ocean space with wind developers.

The Fukushima disaster provided the catalyst for change in Japan's attitude to wind power. By November 2011 the Ministry of Economy, Trade and Industry (METI) had approved a start-up budget of JPY 12.5 billion (US $12.2 million), and a consortium of some of the country's biggest industrial and financial firms had been formed to begin development of a floating wind farm in the Fukushima prefecture. By November 2013, a 2MW Hitachi downwind turbine mounted on a three-column semi-submersible floating platform built by Mitsui was generating electricity in water depths that range from 100 to 200 metres. A 66kV substation, on an advanced spar floater built by Japan Marine United, was also operating successfully.

The second phase of the project is scheduled for 2015, with the installation of two 7MW Mitsubishi Heavy Industries (MHI) SeaAngel turbines, one on a semi-submersible foundation, the other on an advanced spar design. No wind turbine of anything like this power, size or weight has been tested on floating foundations before. The installation and testing of these titans will be watched very closely by the global offshore industry.

MHI's SeaAngel is a rather curious choice of turbine for this project. Unlike the 2MW Hitachi turbine currently operating at Fukushima, the SeaAngel is a conventional upwind turbine, considered less suitable for operating in typhoon-prone conditions. A prototype is due to start onshore testing in May at the Hunterston test centre in Scotland, UK, but MHI has said the machine is unlikely to go into full-scale production. The joint venture established last October by Vestas and MHI will concentrate on Vestas' V164-8MW turbine, with only the SeaAngel's digital hydraulic drivetrain system earmarked for further development.

Hitachi is working on a larger 5MW downwind offshore turbine, the HTW5.0-126, with a prototype due to start at a near-shore site in Japan in September. It has yet to be linked with any floating projects.

METI has indicated that if the testing continues to progress well, there could be a third phase to the Fukushima project - a utility-scale floating wind farm of up to 1GW. But there is a very long way to go before that moves from pipedream to pipeline.

The Fukushima project tends to hog the Japanese offshore limelight, but it is not the only project testing floating foundations. Backed by Japan's environment ministry rather than METI, another high-powered consortium has successfully installed a large-ish turbine on a floating foundation in deep waters.

Data capture

Led by Toda Construction and with other consortium partners including Fuji Heavy Industries, Kyoto University and the National Maritime Research Institute of Japan, this project is located one kilometre from the coast of Kabashima on the Goto Islands in south-west Japan in water depths of 80-100 metres. The project is aimed at providing data on the impact of the turbine on local fisheries, as well as adding to Fukushima's typhoon-resistance information.

The project uses a floating spar for its foundation, and started in June 2012 as a half-scale pilot with a 100kW downwind turbine. A full-scale pilot, like Fukushima supporting a Hitachi 2MW downwind turbine, has been operating since October 2013 on the same site. Although it is generating electricity, which will be sold to the local utility, there are no plans to scale up the development.

Two other floating trials are worthy of mention, though they are extremely speculative in nature. First is the Wind Lens floater developed by Kyushu University. A scale model with two 3kW shrouded turbines was launched in December 2011 for a one-year trial. A larger model is under development. The Modec Skwid, a wind and current hybrid design using a vertical-axis turbine, was due to start testing last October, but a vital component sank at sea during the installation.

Status update... Floating offshore wind projects in Japan (Source: METI/Maine Consulting)

Twice Europe's costs

It is very early days for Fukushima and Kabashima, let alone the others. The most that can be said at this stage is that they show promise, offer a glimpse at deep water offshore wind's potential. But offshore wind in Japan, even on fixed foundations, comes at a cost.

A study group, commissioned by METI to investigate the costs of offshore wind with a view to setting a procurement price, estimate the installation costs of a large (100MW-plus) wind farm on fixed foundations to be JPY 1.07-1.12 million per kilowatt. That works out, roughly, at EUR 7,500-8,000/kW, about double the average cost in northern Europe. On those figures, a wind farm the size of the UK's London Array would cost something very close to EUR 5 billion to build, compared with EUR 2.2 billion for the 630MW London Array. Nor would the project be cheap to keep running, with annual operation and maintenance costs estimated at EUR 163/kW to EUR 220/kW.

The study looked at other scenarios for setting a procurement price. A pitch by an unnamed "commercial operator" for installation costs of EUR3,195/kW, highly competitive even by European standards, and an annual operations-and-maintenance bill of EUR 149/kW, was blithely dismissed by the study's authors. "This report is not sufficient to forecast potential commercialisation risk and facility utilisation rates," it said.

A second scenario investigated offshore wind on easy-to-build sites — near-shore, preferably close to a port, in waters shallow enough to allow fixed foundations. Estimated installation costs range from EUR 3,834/kW to EUR 4,189/kW. That is pretty close to the current position in Europe, where offshore installation costs range from EUR 3,300/kW to EUR 4,300/kW.

The third scenario envisaged fixed foundations offshore projects in deeper waters with the technology more developed and industrialised, while taking into account advantages of scale for the use of larger turbines. This provided installation costs ranging from EUR 5,325/kW to EUR 5,609/kW. No guide costs have yet been issued for floating projects.

Closer to shore

The industrialisation and commercialisation of floating wind power remain some years away, but Annette Bossler, Maine Consulting managing director and an expert on Japan wind's industry, believes Japan will commit to developing deep water offshore wind. "I think industry is serious about pushing this forward, but on the policy side it's more of a mixed perspective," she says. "Some politicians are behind it, others say it's too expensive. It will be interesting to see which group will prevail."

Bossler concedes that the cost estimates published by METI are "horrendous", and points out that Japan lacks an offshore O&M infrastructure. But the development and construction of floating platforms would give a much-needed boost to Japan's shipbuilding industry, struggling against cheaper competition from countries such as South Korea.

"In the end, it largely depends on what happens at Fukushima," she says. "If the tests continue to go well then it's possible that something large-scale could start building by 2018. Do not underestimate how quickly Japan can make things happen once they've made up their minds. But right now it's too early to say."

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