The edifice at the bottom (which, I assume is supposed to be significant in the picture) seems lost and out of focus. The sky's nice, but it can't save the shot.
The sky looks really nice. I'm not sure I like the rocks exposed so much in the foreground. They draw my eye too much, when I'd rather see the sky and the dam.
The subject here is interesting, but the area lit on the left is competing with what I believe to be the main subject. I really like the colors in the sky.
I can't quite tell what's going on. My eyes wander from the light in the sky, the the bright lights in the middle, to the lit foreground. No major focal point to rest on. Nice blues in the sky, though.