Spotted this "green screen" while browsing Green Bytes, the blog of the Horticulture Society of New York. Here's what they said about it:
This screen can actually help conserve energy by providing a layer of insulation, and even act as soundproofing. Plus these plants will grow and fill in the window creating a privacy screen.
Not sure exactly how much energy would be saved with a setup like this, but it sure looks nice! Also, Green Bytes mentioned how they stocked theirs with plants that had varied bloom times, equaling a year round display. Just a thought!