The popular Christian rock group Petra used wind turbines to symbolize the unseen power of Christ. Of course wind energy is also an unseen power. This is a theme often used by German theologian Franz Alt in his speeches and in his books.
The photograph on the cover of the CD shows Belgian Windmaster turbines in the Altamont Pass. Site manager Bill Chapman is mentioned in the credits.
There is also a print of a three bladed rotor, possibly symbolizing the trinity, on the CD itself.