There is no doubt we need alternative energy sources. These alternatives are called renewable energy sources, meaning that no matter how much is used, more will always be available. What kinds of renewable energy sources are there?

Play the Energy Lab: http://www.pbs.org/wgbh/nova/labs/lab/energy/

Find discussion questions for this video and other resources in the Energy Lab collection on PBS LearningMedia: http://www.pbslearningmedia.org/resource/nvel.sci.tech.supply/a-never-ending-supply/