In this article, we describe a practical implementation of a serious game to facilitate knowledge acquisition about renewable energy technologies among youngsters, using the game Serena Supergreen and the Broken Blade. We present the quest design and an evaluation study on the research questions: (1) Did youngsters who played the game have more knowledge about renewable energy technologies compared to those who did not play the game?; (2) How did students perceive the game?; and (3) What did the students recall from the game 11 months after playing it? The study was conducted at a German secondary school (n = 82). Youngsters who played the game had more knowledge on renewable energy technologies compared to the control group (n = 31). In a second round of data collection, 11 months after playing, a majority of students still remembered the game quests. Our results indicate that serious games are a promising approach for introducing basic knowledge about renewable energy technologies.