I like how the wispy cloud looks like it's "blowing" at the windmill in a way. Try adding a bit more sharpness to this, then use levels and brighten a bit and see if you like it. The sharpening "crisps" it up and the levels adds a bit of contrast.
I know those are wind machines but where is the wind? It would be helpful to show some movement to sell the wind theme IMO. This photo also seems a little underexposed. Did you bump the levels or adjust the histogram any to see what impact it made? Not really sure that the grassy hill is adding much to this, unless it's blocking something in the distance that is not visually appealing. I see more wind machines off to the back right that makes me curious for more. All JMO of course. :D Good luck in the challenge.
The lighting is great and your composition is pretty good, but I would have liked to see you get in closer to the windmills and fill more of the frame with that.