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Offshore Wind Power Foundation

Kasaoka Monopile Factory begins operations in April 1, 2024

Project Overview

The government has set a goal of reducing greenhouse gas emissions to virtually zero by 2050, and offshore wind power generation is expected to play a key role in making renewable energy the main power source. In the "Overview of the Vision for Offshore Wind Power Industry (1st)" announced in December 2020, 30 to 45 GW of project formation and a domestic procurement ratio of 60% were set as target by 2040.

In the aforementioned background, we launched offshore wind turbine PJ team in April 2021, and started construction of Japan's first monopile type foundation manufacturing plant.
Of the foundations for offshore wind turbines, the monopile type foundation consists of a monopile as a column and a transition piece for connection with a tower of the wind turbine. Monopiles and transition pieces are extra-thick, large-diameter, and long, super-heavy objects, and their size makes it difficult to manufacture at existing domestic plants. Once our new plant was completed, it will be Japan's first monopile type foundation manufacturing plant.

We will promptly establish a domestic monopile manufacturing base, and in the future, we will add the jacket type foundation, which has already been extensively used in port piers, etc., and aim for a full lineup of all-made-in-Japan fixed-bottom foundations. We will surely respond to the rapidly expanding construction demand for offshore wind power generation and contribute significantly to the realization of carbon neutrality.

If you would like to know more about our design technology development of offshore wind power foundation and construction plan of monopile manufacturing plant, please refer to the following JFE Group technical report.

Action Policy: Full Lineup of All-made-in-Japan Fixed-bottom Foundations

Transition Piece

Domestic Manufacturing Base

The new monopile plant is scheduled to be built in Kasaoka City, Okayama Prefecture, on the premises of JFE Steel West Japan Works (Fukuyama area). Primary steel pipes of monopile and transition piece are manufactured at the new plant using large single and heavy plates manufactured by JFE Steel. After that, the monopile will be transported by vessel directly to the construction site of the offshore wind power generation project. On the other hand, primary steel pipes of the transition piece are transported by vessel to JFE Engineering Tsu Works, where secondary steels and internal parts are installed to complete the transition piece, and then transported from Tsu Works to the construction site by vessel.

New monopile plant in Kasaoka City,
Okayama Prefecture (200,000m2)

  • Monopile manufacturing
  • Transition Piece pipe manufacturing (Transported to Tsu Works)

JFE Engineering Tsu Works in Tsu City, Mie Prefecture

  • Transition Piece final assembly
  • Jacket assembly

Overview of New Monopile Plant

Construction site Kasaoka City, Okayama Prefecture
(JFE Steel West Japan Works Fukuyama area)
investment amount Approximately 40 Billion yen (Plant building, Mechanical equipment, Quay reinforcement)
*Includes facility reinforcement cost of Tsu Works
Construction start June,2022 Site area Approximately 20ha (includes storage area)
Operation start April, 2024 Production capacity Approximately 80,000~100,000 tons per year (Approx. 50 sets)
Length of shipping quay 200m (Quay total length 400m) Quay depth -11m

Capable Monopile Specification

Diameter Maximum around 12m
Thickness Maximum around 130mm
Length Around 100m
Weight Around 2500 tons

Monopile Fabrication Process

Overview of Tsu Works (Fabrication of transition piece and Jacket)

Tsu Works is our steel structure manufacturing base and the largest steel structure production plant in Japan. Tsu Works has been operating as our main factory so far, manufacturing bridges represented in Japan such as the Akashi Kaikyo Bridge, overseas bridges such as the Japan-Egypt Friendship Bridge (Suez Canal Bridge), and coastal structures such as caissons and seawall. Utilizing our experience in manufacturing a wide variety of steel structures and our expansive site and quay that can accommodate large-scale offshore wind power generation foundation, we perform the final assembly of transition pieces (installation and painting of secondary steels) and manufacture of jacket-type foundations.

Japan's largest steel structure production plant
Weight of cutting and preparation 30~40 thousand tons per year
Site area
(includes marine dock)
One million m2
Total employee Around one thousand
Fabrication image at Tsu Works

Fabrication Process of Transition Piece (Secondary steel fabrication)

For Obtaining Certification

Currently under preparation for obtaining DNV factory certification.

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