NSK Joins Forces to Tackle Offshore Wind Wake Effects, Enabling Japan’s Floating Turbine Farms

With ambitious climate goals in sight, Japan aims to expand offshore wind energy rapidly. However, floating wind farms come with complex engineering challenges. One critical issue is the wake effect – disruptive turbulent airflows caused by spinning turbine blades. To tackle this, the Japanese government is funding a major research project to evaluate and predict wake effects for offshore wind optimization. Bearing manufacturer NSK will lend its expertise, collaborating with universities and industry partners.

The government of Japan has set a goal of achieving carbon neutrality by 2050. Floating offshore wind turbines are expected to make a significant contribution. However, harnessing offshore wind on a large scale first requires solving the technical puzzle of wake effects.

Wind Turbines: What is the Wake Effect

Wind turbines extract energy from the wind, slowing the wind speed behind the turbine. This generates a turbulent trail of slowed wind, known as a wake. Understanding wake interactions enables optimal wind farm design.

Wake effect occurs because wind turbines take kinetic energy from the wind to generate electricity. Consequently, the current after passing through the turbine, has reduced speed and energy. This can be visualized by adding smoke to the air flowing through a turbine, revealing the slower turbulent wake trailing behind. Turbines are typically spaced over 5 rotor diameters apart in the wind direction to minimize detrimental wake interactions.

The wake effect depends on various factors. Predominant wind direction guides turbine spacing, with greater separation in that direction. Turbulent versus smooth airflow also impacts wake behaviour. Detailed site studies, wake modelling, and wind farm optimization software help mitigate wake losses. Properly accounting for the wake effect maximizes wind farm production.

This phenomenon occurs when arrays of turbines interact, resulting in reduced energy generation, increased structural loads, and more significant fatigue on downwind turbines.

To accelerate the deployment of floating offshore wind farms, the New Energy and Industrial Technology Development Organization (NEDO) is leading a research project on predicting and evaluating wake effects. Funded by the Japanese government, the ambitious project brings together key partners Kyushu University, Toshiba Energy Systems, Hitachi Zosen, and NSK.

The project will conduct studies in a specialized wind tunnel facility at Kyushu University. The objectives are to understand the wake interactions of floating turbines, develop predictive technologies, and map out a future research pathway through industry-academia collaboration. Since wake effects are relatively unexplored for floating turbines, the findings aim to resolve issues for installing wind farms at scale.

As part of this initiative, NSK will focus on enhancing the reliability of wind turbine bearings. By analyzing changes in turbine loading from wake effects, the company can gain insights to optimize bearing design. With expertise in specialized bearing solutions, NSK aims to support greater adoption of wind power generation.

This collaboration brings together engineering leaders across industry and academia. The wake effect is one of the most pressing challenges for viable large-scale floating offshore wind. As Japan works to rapidly deploy offshore renewable energy, projects like this will provide critical insights needed to optimize wind farm engineering. With its expertise in bearings innovation, NSK is well-positioned to help create next-generation wind energy solutions.