Currently, all projector screens are merely blank faces which reflect back light. This light is largely wasted. Although still in the very early stages of development, the idea is to create a projector screen that would be able to absorb light energy from the projector as well as reflect sufficient lighting back to the audience. As I am currently a high school student, I am not quite sure how to achieve this. A possibility could be to perhaps utilize a set of reflecting mirrors which reflect back into the audience and into the photo-voltaic cells behind. Also, one-way mirror technology may also do the trick. Later development and improvements could surely increase efficiency, with the goal being near self-sufficiency.