Honestly, neither really trip my trigger, but I lean towards the second one because my eye is more free to move around the frame and I therefore find it more interesting. In the first one, the closest (and therefore largest looking) windmill is smack-dab in the center of the pic and my eye goes to it and stops there. The second pic has more interesting negative space and the closest/largest looking turbine is not centered which lets my eye wander around the image a little more and take in the colors and shapes and lines.
I think I'd prefer the second one even more if it were flipped so that closest/largest looking turbine was on the left side, rather than the right.