The Green Education Foundation found that this lesson plan, written by the Texas State Energy Conservation Office, is right up their alley when it comes to teaching sustainability. It is ideal as a first lesson plan on photovoltaic systems as an alternative to fossil fuel driven systems. High schoolers read an article on photovoltaic cells and explain its applications. They test PV cells for the response to light, shade, angle, and sun intensity. This is a top-notch resource!