Here may be the answer to another big part of the puzzle. "The paper presents the interim results of the StEnSea project, which comprises the development and testing of a novel pumped hydro storage concept for storing large amounts of electrical energy offshore. The following paragraphs introduce into the general description of the concept and give an overview of possible installation sites for full-scale commercial systems. Additionally, the building and further preparations of the prototype testing of a 1:10 scale model are described." https://www.sciencedirect.com/science/article/abs/pii/S2352152X17302207?via%3Dihub
Here may be the answer to another big part of the puzzle. "The paper presents the interim results of the StEnSea project, which comprises the development and testing of a novel pumped hydro storage concept for storing large amounts of electrical energy offshore. The following paragraphs introduce into the general description of the concept and give an overview of possible installation sites for full-scale commercial systems. Additionally, the building and further preparations of the prototype testing of a 1:10 scale model are described." https://www.sciencedirect.com/science/article/abs/pii/S2352152X17302207?via%3Dihub
https://arstechnica.com/science/2020/08/black-paint-on-wind-turbines-helps-prevent-bird-massacres/