Norwegian Subsea delivers tailormade motion sensors for floating wind

Freeing offshore wind power from bottom-fixed designs creates new possibilities. In fact, many believe that floating wind is the next wave in renewable energy. But the addition of a floating platform brings new challenges.

Unlike bottom-fixed turbines, floating offshore wind turbines are prone to six degrees of platform motion, which can affect the power generation, structural life, operation and maintenance of the turbine.

“Accurate motion measurement is especially crucial in the growing floating wind industry,” says Dukan.

Norwegian Subsea makes affordable motion sensors with high-end performance for floating offshore wind applications. Its motion reference units (MRU), or 6DoF sensors, measure real time attitude (roll, pitch and yaw) and linear motions (surge, sway and heave), including the corresponding velocities and accelerations.

The MRU consists of a high accuracy, 3-axis MEMS (microelectromechanical systems) gyroscope and 3-axis MEMS based accelerometer. Data from the internal sensors are processed with a novel sensor fusion algorithm.

“As an innovator of this technology, our goal has been to provide the best accuracy, even in challenging environments. Our combination of new sensor technology and knowledge about sensor fusion algorithms lets us deliver highly accurate and reliable motion sensors,” says Dukan.

Moreover, Dukan notes that the MRUs are the most affordable on the market. “Similar sensors cost at least two to three times more than ours. It’s our innovative technological approach that keeps the cost down,” he says.

The MRUs are highly versatile, enabling a wide range of applications.

“Motion sensors are needed in several stages of the life cycle of a floating offshore wind farm. For example, they are used to monitor motion for structural integrity purposes and control the pitch of the blades in real time. They are also needed for assessing potential wind farm sites,” explains Dukan.

In addition, the MRUs provide reliable data in real sea conditions, where complex motion patterns, vibrations and horizontal accelerations are common. The sensors are small and consume relatively little power, enabling installation almost anywhere.

The flexible interface makes the sensors easy to install and use. “We aim for plug-and-play. At the same time, this is a niche product and there are no industry standards. We work with users to ensure that the interface functions seamlessly,” says Dukan.

“The market for MRUs and motion sensors for floating offshore wind is directly linked to the number of installed structures and wind farms,” says Dukan.

Given this, the staggering growth expected in floating offshore wind bodes well for Norwegian Subsea. Annual floating wind installations are projected to increase by 83 per cent from 2021 to 2026. By 2031, the production rate is expected to reach 9 990 MW, up from 57 MW.

Field tested, the MRUs have been installed on floating wind structures, lidar buoys, active heave compensated cranes and motion compensated gangways. Target customers are system integrators for offshore wind developers and wind turbine manufacturers worldwide.

“We are continually discovering new applications for our MRUs in marine, subsea and land-based industries,” concludes Dukan.