As China and the United States become the top two carbon emitters in the world, it is crucial for citizens in both countries to construct a sophisticated understanding of energy consumption issues. This interview study examines how U.S. and Chinese students compare in explaining and arguing about two critical energy consumption issues: burning fossil fuels and using electricity. In particular, we focused on using scientific knowledge to explain and argue about these issues. Based on relevant literature and our previous research, we developed a model to guide separate assessment and evaluation of students' argumentation and explanation. We conducted clinical interviews with 40 biology majors, including 20 U.S. students and 20 Chinese students. This study generated several important findings. First, Chinese students tended to be less consistent across explanations and argumentation, and their levels of argumentation were lower than their levels of explanation. Second, in comparison to their Chinese counterparts, U.S. students provided more scientific arguments but many fewer scientific explanations. Finally, although all participants were college students and had completed at least one introductory level science course before the interviews, some of their explanations and arguments were based on informal ideas rather than matter and energy. We discuss the possible interpretations of these findings and their implications for teaching and learning of scientific explanation and argumentation in both countries.