Check out this innovative idea for saving energy.
With its concept for a new approach to outdoor lighting, the group asks: What if streetlights could respond to ambient moonlight, dimming and brightening each month as the moon cycles through its phases? On clear nights when the moon is full, streetlights might even turn off completely. The scheme, which they call “lunar-resonant streetlights,” could save as much as 80–90 percent of the energy used in streetlighting while bringing back the experience of moonlight and stargazing to urban areas.More at Civil Twilight.