After being locked out of the works building near the power-generating wind turbines, you will be tasked with finding the key to get inside the works building. The game gives you a rough idea of where to find it but is not all that clear. Here is what you need to do.
Head west from the works building and return back to the small town. If you explored this area when you first arrived, you will remember seeing two galaxy members chatting to each other in the northwest corner of the area but they would not engage with you. Return to this area.
The visual style here is deceptive but it is possible to head through these trees to a new area where you can engage in a pokemon battle. Once you win, you will be able to speak to the man here and he will give you the work’s key.
Once you have the key, you can return to the building and unlock the door to get inside and progress on with the quest.