There is a quick and easier way of completing this level. Please note that if you complete the level this way then your still going to need to play through the level normally to unlock "electricity 101" "will it fry?" "delivery boy" and "thief". Though it is possible to complete "delivery boy" and "thief" by working your way around the map, for "thief" just stay on top of the wall at the start and navigate your way to the big statue
The Thief achievement in Human Fall Flat worth 58 pointsSteal the battery from the statue in "Power Plant"
and for delivery boy:
Also i will be using the term "twist climbing' since i am not sure if this has an official name, but there is a mechanic in the game where you can climb across a wall in an almost horizontal fashion, grab the wall with one hand, lets say the left arm, if going left look right until doing a 180, then grab with the right hand, rinse and repeat.
At the start of the level use the pole to block the fan, once done walk out and walk to your right. then jump around the corner of the wall and grab it, then twist climb until you arrive at the ground.
Then walk past the yellow truck and keep going forward past these:
Once you pass them you will come to a little ramp leading into the ground, keep walking past it and dont go inside it, you will come to these large "chimneys" and you want to go into the third one, since it has a hole in the side, then you use the wind from the fan and try to aim yourself towards the next big "chimney" since that is the end of the level/map.
If you would like a video guide on this here is a pretty decent one i found:
though when going for the fan jump line yourself up with the right side of the hole, then walk in, this should make directing yourself quite easier.