Uckley-Nord comprises 10 Nordex N131/3300 turbines at a site in Brandenburg, north-east Germany. It was completed at the end of September.
Trianel CEO Markus Hakes said the acquisition brings the firm closer to its target of owning 275MW of onshore wind and ground-mounted solar projects by the end of 2018.
In addition to Uckley-Nord, Trianel and its local partners currently own wind projects in Rhineland-Palatinate, Bavaria and Hesse, totalling around 56MW of onshore wind that is either in operation or under construction.
The company and its partners are looking to invest around €500 million in the expansion of renewable energy "in the coming years".