Floating turbines - Japan enters the stage

JAPAN: In recent years, discussion of floating offshore wind technology centred on Europe and the US as governments there increasingly supported research and development.

The 2MW offshore wind turbine for Fukushima

In recent years, discussion of floating offshore wind technology centred on Europe and the US as governments there increasingly supported research and development.

Statoil of Norway and US company Principle Power launched full-scale pilot projects. However, for more than a decade, Japanese academic institutions, government organisations and private industry have developed numerous designs for floating foundations. Very little was published in English, but a wealth of information has long been available in Japanese.

Yet as a country better known for its historic dependence on nuclear power — at least until its catastrophic March 2011 earthquake in eastern Japan shut most of the country’s nuclear capacity — Japan was neither on the global offshore wind industry’s radar, nor did the country promote itself as a player in this field.

Japan may soon assume a much higher profile. More than 70% of the world’s offshore wind resource is located in deep water around the world, meaning that floating foundations are the long-term future for the offshore wind industry. Japan’s growing know-how in floating technology is likely to give the country a key strategic edge in penetrating overseas markets.



The shape of the seabed surrounding Japan has driven the Asian country’s offshore industry towards floating platforms. The vast majority of Japan’s offshore wind resources are in deep water, defined as depth greater than 100 metres. If the country ever hopes to develop offshore wind power, floating technology is a requirement.

In addition to the domestic conditions, export-oriented Japan has always been very much aware of the potential market in other parts of Asia, Europe and North America. According to studies by the US National Renewable Energy Laboratory (NREL), a significant majority of US offshore wind resources are in water deeper than 60 metres.

This makes the US an obvious target market for Japan. The country’s wind sector has had to look abroad anyway: frustrated by weak government support for offshore wind in its home market and obstruction from the fishing industry and other powerful maritime stakeholders, Japanese engineering giant Mitsubishi Heavy Industries has been trying to break into European offshore wind.

Japan’s maritime-logistics industry also has no interest in sharing the ocean because a large percentage of Japan’s domestic freight is transported by coastal vessels rather than by rail or truck.


Disaster sparks innovation

The 2011 earthquake, tsunami and nuclear disaster that devastated Fukushima also shattered the country’s nuclear-focused energy policy. Even today, only two of 54 nuclear reactors are operating, a reality that has forced Japan to embark on changing the energy mix. Wind power, including floating offshore wind, is part of this.

Within a few months of the catastrophe, the Japanese government issued a budget proposal for a floating offshore wind demonstration project off the Fukushima coast.

Local offshore wind resources, proximity to load centres, existing onshore cable interconnects, as well as the potential economic benefits for the battered region made this a viable location.

In November 2011, without major debate, Japan’s parliament approved the budget. A request for proposals was issued the following month and in March 2012 the government announced that the project would be carried out by a consortium led by trading giant Marubeni in the project-management role.

The ¥18.8 billion ($189 million) project will be built in two phases: the first will see construction and deployment of a 66kV floating substation, using a floating spar — a type of floating platform used in very deep waters — developed by shipbuilder Japan Marine United and the University of Tokyo, as well as a 2MW downwind turbine on a semi-submersible foundation built by Mitsui. Grid connection and commissioning of both was expected by the time of publication.

The spar with floating substation and the Mitsui semi-submersible foundation were towed towards Fukushima in late July, demonstrating that the project is on track.

In phase two, the installation of two 7MW Mitsubishi hydraulic turbines, one on a Japan Marine United floating spar and one on Mitsubishi’s own semi-submersible foundation, are planned for commissioning by 2015.

But the Fukushima project is not the only floating foundation project in Japan. In 2012, a separate consortium in Kyushu installed a half-scale pilot of a floating spar with a 100kW turbine.

This is being replaced by a full-scale version with a 2MW turbine, also expected to go fully operational imminently. The installation of two gravity-foundation turbines, one at the entrance of Tokyo Bay and one in Kyushu, will provide performance and ecological data that can be compared with data collected at the floating sites.

These two full-scale floating spars and one full-scale semi-submersible foundation have already given Japan the leading position in floating offshore wind demonstration projects.

This can be the starting point for a 100MW-plus floating offshore wind farm to be built off the Fukushima coast, as well as further projects in other parts of Japan’s maritime exclusive economic zone.



The projects’ designers had to consider many risk factors characteristic of Japan and other east Asian geographies.

The floating foundation designs underwent extensive simulation, as well as tank testing that emulated typhoon and tsunami conditions. There are specific concerns over how mooring systems will respond to the force applied by typhoon waves and surface movement caused by a tsunami.

The fishing industry, while more welcoming towards offshore wind now than prior to the earthquake, still needs to be convinced.

Meanwhile, the Japanese government is investing in a study of what standards are needed to ensure safety for maritime vessels navigating around floating offshore wind farms.

The government’s latest five-year ocean policy, released in May, lists development of such standards, as well as international adoption, as key requirements for offshore wind to succeed in Japan.

But the biggest challenge is Japan’s fragmented and underdeveloped onshore transmission infrastructure. The best resource areas lack adequate grid connection to load centres.

In fact, insufficient transmission capacity and interconnections between the territories of Japan’s ten utilities are the biggest obstacle to all development of renewable energy.

Until the March 2011 catastrophe, there was little appetite across Japan for investment in inter-regional connections. This has now changed. But in Japan, as in Europe and the US, the debate is not about the need for investment but who pays for it. Onshore transmission bottlenecks could be as big a hurdle for offshore wind as the country’s difficult maritime terrain.


Broader implications

What do Japan’s floating projects mean for the rest of the world? There are more than 30 floating wind-turbine projects around the globe. Excluding Japanese projects, 12 of these are full-scale installations are expected online over the next two to three years.

The race is on, and the speed with which Japanese companies are implementing their projects is putting pressure on US and European technology developers. In Europe, the UK, Norway, Spain and France are leading the pack.

In the US, the question is whether Principle Power’s 30MW WindFloat offshore project, off Coose Bay, Oregon, will receive additional US Department of Energy funding or whether the US government will relinquish the lead in developing floating offshore technology in the Pacific Ocean to the Japanese.

One thing is clear: with more than 70% of global offshore wind resource in deep water, floating foundations are the long-term future for the offshore wind industry.

Annette Bossler is owner and managing director of Main(e) International Consulting, a firm based in the US state of Maine. She has worked in Japan for seven years.