The discussion is over 50 years old: fossil energy will not last forever and it also pollutes the environment. Nuclear energy is risky and the problem of nuclear waste disposal is unsolved. So renewable energy resources are playing an ever more important role. In the experiment "Renewable Energy - where will tomorrow’s energy come from?" participants can have a look into the future. Using the SmartCity demonstrator students investigate the self-regulating strategies of an "intelligent city". They predict its energy requirements and devise methods for meeting them in an environmentally responsible and sustainable way.