Have a look at this site. You may find it useful for intermediate students:
http://www.headsupenglish.com/index.php/upper-intermediate-students/upper-intermediate-news-lessons/upper-intermediate-environment-lessons/277-green-living
or for beginners:
http://old.solar-aid.org/sunnyschools/blog/Unit%202.pdf?url=/sunnyschools/blog/Unit%202.pdf&gclid=CM65rc2jn7cCFahcMgodcUMAsA
All the best