where can i get darrieus rotor?

[Nutnut]

ive looked online and in game and cant find anything

[TrueChaoS]

You make it.

Most level 3 Ark upgrades require you to make one or more of the lower level upgrades that effect the same building (in this case, offshore wind parks).

If you don't have it available, keep doing basic research (energy production in this case) until you unlock it.

[Chakane048]

http://anno2070.wikia.com/wiki/Offshore_Wind_Park
http://anno2070.wikia.com/wiki/Academy_Research_Projects

Research under Energy -> Offshore
If you don't have you need to do basic research to unlock it, it's explained in the article.

You can always search the anno 2070 wikia first, take some time reading it