The turbines will be the largest yet installed on floating foundations.
They will be installed on Principle Power’s ballasted, triangular, semi-submersible WindFloat foundations 20km from the north-west Portuguese coast in water depths of 100 metres.
MHI Vestas explained that the WindFloat Atlantic project would provide insights about installation and commissioning techniques, turbine and foundation performance, how main components interact with one another, and power production.
The company’s chief technology officer, Torben Larsen, said: "With floating technology accelerating towards its full potential, this project will provide many critical insights that will be carried forward into future projects."
UK firm JDR Cables will supply 66kV inter-array and export cables for the floating array, which is being developed by WindPlus, a consortium led by EDP Renewables, for the 25.2MW project. The consortium also includes Mitsubishi, Chiyoda, Engie and Repsol.
WindFloat Atlantic is due online in 2019.