CENER presented the fully coupled Multi Rotor Wind Turbine Tool “MUST”, most likely first in the world, in the Multi-Rotor congress of Hamburg.
Today, there is a dominant wind concept for wind generation technology, single-rotor tri-blade horizontal axis. That’s the winning technology. In 2021, there were 837,000MW of commercial wind turbines installed worldwide, of those, 0MW were commercial multi-rotor.
However, as we shift from onshore to floating wind, there is a wide range of multi-rotor floating wind power generation designs. Designs that are difficult to categorize; the only common factor is that they include more than one rotor per floating structure.
The Hamburg congress brought together international stakeholders working to make this technology a reality. In that sense, it was interesting to know the different points of view of: wind farm developers, multirotor developers, certification bodies, turbine OEMs, blade OEMs and Technology Centers.
Many of the stakeholders had the opportunity to share their vision of the technology and debated the most difficult question. Why can these multi-rotor designs challenge the “mono-rotor dominant design”? Shouldn’t the dominant design also be the best alternative at sea?
Two categories of potential advantages were explained at the congress:
- Reliability: The offshore business case is based on extremely large wind turbines. These “Mega-Turbines” incorporate the most advanced engineering, where innovative materials are demanded to the limit of their properties and combined in innovative manufacturing processes. In addition, these mega-turbines have had little time to mature and optimize. The combination of rapid innovation and short maturation time can result in an increased risk of reliability issues. On the other hand, multi-rotor technologies scale power with up to 126 turbines of 1MW. These 1MW turbines are well known throughout the supply chain (engineering tools, materials, and manufacturing processes), and have potentially minor reliability issues.
- Cost of Logistics, Installation and Maintenance: Mega-wind turbines are increasingly complex to transport, install and maintain on the sea. Their components are heavy and big, near the capacity limits of the infrastructure and equipment that must handle them. Multi rotor solutions propose to divide the problem into more turbines, more components, but lighter and smaller. Three blades of 120mtrs length (16MW) or six blades of 80mtrs length (8MW)?
In addition to the interesting, and different, value proposition of multi-rotors, the event also served to present the progress that international technology and research centres have made in the engineering tools of design, simulation and certification for multi-rotor. In this section, CENER stood out with the presentation of MUST, the first tool in the world where all physics are fully coupled.
The reality of wind industry design and simulation software is that it has not been developed with floating multi-rotor in mind. It is developed for single-rotor systems and fixed solutions, which have then been adapted for offshore wind. CENER’s tool, MUST, has been developed specifically for floating multi-rotor, taking also into account the floating aerodynamic coupling, due to the interaction between rotors and the impact of wave-induced movements on aerodynamics. These factors have an impact on production and loads, and must be studied in detail to provide reliable, long-lasting solutions.