Offshore wind critical to secure Japan’s energy security, and continued focus on RD&D needed, says the Carbon Trust

Japan’s offshore wind industry needs to accelerate Research, Development and Deployment (RD&D) efforts to reduce the country’s exposure to the highly volatile costs of imported energy and secure its future energy supply, according to a series of reports released today by the Carbon Trust. To realise the potential of Japan’s abundant wind energy resource the pace of technology RD&D to develop technology solutions capable of surviving Japan’s unique and challenging offshore conditions, needs to be accelerated.

The analysis, funded by the UK government’s Foreign and Commonwealth Office, identifies technical, policy and regulatory challenges faced by the industry. It maps existing local solutions against where experience from the more developed European offshore wind industry could be leveraged to cut consenting, planning and construction costs, and speed up deployment of offshore wind in Japan.

The research identified a number of key areas to focus on including;

  • Increase RD&D in innovation to reduce development, construction and operational costs. Key areas to focus on include floating wind, novel foundations and collecting offshore environmental measurements.
  • Increase availability of vessels for installation, operation and maintenance. Explore alternative deployment strategies for example foundations floated out to site, possibly as an integrated structure including the turbine. Companies could look to import bespoke vessels, or construct them locally.
  • Use of floating LIDAR technologies could help to significantly reduce costs of gathering meteorological data at site-scale, particularly given the challenges of deep water sites.
  • Assign consenting authority to one central department and streamline environmental impact assessment regulations, to reduce length of process. Undertaking studies to better understand the impact of wind farms on marine species can support this.

Offshore wind has emerged as a potential growth area for energy generation in Japan.

Statements from the Japanese government have expressed a commitment to develop and increase renewable power technologies and deployment in Japan. Furthermore, a national target set by the Japanese Wind Power Association (JWPA), 37 GW of offshore wind power is expected to be installed by 2050, including both bottom-fixed and floating offshore wind turbines.

Al-Karim Govindji, Senior Manager at the Carbon Trust commented, “Japan’s offshore wind industry is relatively embryonic as historically the emphasis has been on nuclear. Although in the past Japan excelled at shipbuilding, it presently lacks experience in large scale engineering projects offshore; experience the UK offshore wind industry has benefited from through decades of oil and gas exploration. It should be noted that challenging climatic and geological factors in Japan mean that European methods of construction and installation cannot always be applied. Japanese manufacturers are leading the way in developing bespoke solutions needed to cope with Japan’s challenging environmental conditions; however our analysis shows that experience from Europe on developing the right technologies and regulatory market conditions to foster an industry with enormous potential could deliver results quicker.”

Japan has an estimated 1,570 GW of offshore wind potential in comparison to 280 GW of onshore wind, which is constrained by land availability and geography. However 80% of the offshore wind resource is located in a water depth greater than 100 metres which will require bespoke deep water turbine technology, for example floating turbines. That said, the target for fixed foundations is significant at 19GW by 2050. Thus, developing expertise in this area, for example by leveraging known technologies from Europe, could accelerate Japan’s offshore wind expertise.

The majority of existing installed wind capacity is based on fixed turbine technology.  However, if Japan is to meet its national target of 37 GW installed capacity by 2050, novel floating technologies that can withstand the unique conditions in deep waters around Japan will also need to be developed. Indeed, some of the early demonstrators have been of floating foundation structures.

Offshore wind farms in Japan have to endure harsh conditions including typhoons, tsunamis and earthquakes. The impact of this unique mix of environmental factors on the true cost of energy from offshore wind is not well understood. This understanding will be key to help the Japanese government set a realistic Feed-In-Tariff (FIT) to incentivise and de-risk private investment.

The reports also identify other barriers including lack of grid transmission capacity, lengthy consenting time due to conflicts with the powerful fishing cooperatives and costly environmental impact assessments which can take up to 4 years. The need to bolster investment into port infrastructure and the development of a local supply chain around deep water foundations and installation vessels are also areas that need to be addressed.

The full reports can be read in detail here:


Detailed findings and overview of barriers:


  • Undertake detailed wind resource and geotechnical assessments to help developers identify the most promising sites for development, and determine which foundation designs to use.
  • Use of floating LIDAR technologies could help to significantly reduce costs of gathering meteorological data at site-scale, particularly given the challenges of deep water sites.
  • Improve consenting process by assigning consenting authority to one central department and streamlining environmental impact assessment regulations. Undertaking studies to better understand the impact of wind farms on marine species can support this.
  • Gain deeper experience of operating wind farms: partnering with European companies could be a way to achieve this.  


  • Achieving >95% availability is critical to help the economics of wind farms and so ensuring gearbox and electronics reliability is critical. Collaborating with European organisations to make use of their test facilities can support R&D for next generation turbines.
  • Develop a set of standards that can be adopted internationally to put Japan at the forefront of typhoon-resistant turbine design.


  • Depending on site geotechnical and metocean conditions, there are a number foundation designs from the European market which could be deployed in Japan. However, incorporating earthquake resistance, gaining accreditation by ClassNK, and demonstrating the technologies in appropriate site conditions will be crucial next steps.
  • Floating technology also requires further RD&D to reduce costs to make the technology competitive with fixed structures. Reducing steel and improving mooring and anchoring systems will need to be a key area of focus.


  • A lack of large installation vessels is a major bottleneck in Japan. Using foundations which can be floated out to site, possibly as an integrated structure including the turbine, could be a solution. Companies could look to import bespoke vessels, or construct them locally.
  • Given the concern regarding the impact of wind farms on fisheries in Japan, limiting noise by using novel piling methods and noise mitigation techniques could reduce the environmental impact of offshore construction.


  • Grid capacity is a major barrier to increasing the share of renewable in the Japanese energy mix. Grid upgrades are planned, but devising a commercial model to protect developers and consumers from excessive additional costs will be key.
  • With floating projects, developing robust dynamic cables will be a major focus, particularly as cable voltage increases for larger arrays, namely 220kV export cables.


  • Optimising O&M strategies is important to reduce LCOE in offshore wind farms. While strategies will vary depending on site location, Japan can look to Europe for technologies which can accurately monitor turbine conditions to detect necessary repairs and improve the accessibility of turbines.
  • For example, Japan does not yet have a wide range of access vessels and transfer systems to enable safe and year-round access to turbines so that maintenance and repairs can be undertaken.


For further information please contact the Carbon Trust press office on 020 7170 7050 or email

About the Carbon Trust

The Carbon Trust is an independent company with a mission to accelerate the move to a sustainable, low-carbon economy. The Carbon Trust:

  • advises businesses, governments and the public sector on opportunities in a sustainable, low-carbon world;
  • measures and certifies the environmental footprint of organisations, products and services;
  • helps develop and deploy low-carbon technologies and solutions, from energy efficiency to renewable power