What is best practice?
Another user added the wind turbines as area (way).
I think as building is ok, it is an additional information.
Also as node, what is quite common is ok.
Right now I doubled the information.

Is it ok to keep both, way ( or better building) and node?
How to transfer way/building into node?
Or forgett about the nodes? (But nodes are quite common for the whole world turbines; search for node[generator:source = wind >> 100k results)

Thank you clearing up this.