Energy literacy is multidimensional, comprising broad content knowledge as well as affect and behavior. In this study, an assessment was designed using six contextualized test units to examine student energy literacy. A total of 2,066 secondary students participated in the survey. The results indicated that student energy literacy is low, particularly with respect to the dimension of “reasoning on energy controversies”. Qualitative analyses of student written responses to various question items revealed that students have misconceptions of biomass energy and misconstrue the sources of greenhouse gas. Inter-correlation among the dimensions of energy literacy indicated that energy knowledge and behavior are more closely correlated with each other than are affect and behavior. The students in southern Taiwan scored higher on energy literacy assessments than did the students in northern, central, as well as eastern Taiwan. These findings are a reference for developing energy-related curricula and educational materials to improve student energy literacy.