Gazelle’s pivoting arms could stabilize massive floating offshore wind turbines

Gazelle Offshore Floating Wind Platform
Gazelle claims that its groundbreaking floating wind platforms can support massive offshore turbines up to 20 MW while maintaining cost-efficiency. Images © Gazelle Wind Power

Irish company Gazelle has unveiled the third generation of its innovative floating wind platform design, which it claims can stabilize offshore wind turbines with capacities up to 20 MW. The new platform design aims to reduce weight, cost, and sea floor cable tension while addressing the challenges associated with deep-water offshore wind installations.

Offshore wind power is a promising source of clean energy, but the most valuable resources are often located in deep waters where traditional fixed foundations are impractical and costly. Floating offshore platforms offer an alternative; however, designing a cost-effective and scalable floating base that can handle the colossal forces exerted by large turbines has been a major engineering challenge.

Gazelle believes it has found a solution with its unique platform design, which combines elements of semi-submersible and tension leg platform approaches. The third-generation design connects to the sea floor on three sides, with cables running over pivoting arms and attaching to a heavy counterweight suspended beneath the platform. This passive system balances the forces from waves, tidal motions, and the turbine tower’s wind-induced torque, reducing pitching motions and increasing efficiency.

The resulting platform is significantly lighter and smaller than traditional semi-submersible designs, reducing steel usage by up to 70% and lowering costs by around 30%. Additionally, Gazelle’s “dynamic mooring” system exerts 80% less load on the sea floor tethers than a typical tension leg platform, maintaining tilt below one degree while permitting some vertical movement.

Gazelle Offshore Floating Wind Platform Design
The Gazelle system (center) represents a hybrid approach, merging elements of semi-submersible and tension leg designs.

The new platform design can reportedly support wind turbines up to 20 MW in capacity, larger than any existing offshore installations. Gazelle claims that the design is modular, easy to manufacture, and simple to tow and deploy without requiring specialized equipment, cranes, or port facilities.

Gazelle has conducted small-scale model tests at the University of Cantabria’s Environmental Hydraulics Institute in Spain, verifying the platform’s claims. The company has also received the first “Statement of Feasibility” for an offshore wind platform from DNV, a classification service provider specializing in the lifecycle analysis of offshore installations, particularly in the renewable energy, oil, and gas sectors.

Gazelle Offshore Floating Wind Platform Pivoting Arms
Massive pivoting arms connect three sea floor tethers to a counterweight positioned beneath the Gazelle platform.

In 2021, Gazelle raised US$14.1 million and signed a Memorandum of Understanding (MoU) with Maersk Supply Service to develop a 2 MW pilot plant in the Canary Islands. Although the project was slated for completion by Q2 this year, the current status remains unclear. Gazelle has also announced a partnership with WAM Horizon on another pilot project in Portugal, but no details regarding size, timelines, or the nature of the collaboration have been disclosed.

Gazelle Offshore Floating Wind Platform Small-Scale Testing
During wave tank experiments in Spain, a smaller-scale version of an earlier design validated the company’s assertions by maintaining pitch movement under one degree.

Despite the lack of concrete progress updates, Gazelle’s platform design is mechanically intriguing, aiming for a low Levelized Cost of Energy (LCoE) that has not yet been published. The offshore wind industry will be closely following the development of this technology in the coming months. To see how Gazelle’s innovative design works, watch the video below.

Source: Gazelle Wind Power