What is the role of the Department of Energy (DOE)?

The primary role of the Department of Energy (DOE) encompasses overseeing research and development programs related to nuclear safety, security, and the management of nuclear weapons. The Department is heavily involved in ensuring that the U.S. nuclear arsenal is safe, secure, and effective, which includes maintaining and modernizing nuclear warheads. This aspect of the DOE's responsibilities is critical for national security and involves extensive work in laboratories and collaboration with various agencies to ensure compliance with non-proliferation treaties and to enhance the nation's technological capabilities concerning nuclear deterrence.

While the other roles mentioned, like policy development for energy efficiency or regulating fossil fuels, are indeed part of broader energy management and sustainability efforts, they do not encapsulate the more specific and significant military and security-related functions tied to nuclear weapons that characterize a critical aspect of the DOE. Hence, the focus on oversight of nuclear warheads aligns strongly with the foundational mission of the DOE in relation to national security.