Steel Upgrading Partnerships and Emissions Reduction Act or the SUPER Act of 2021 This bill requires the Department of Energy (DOE) to establish programs to reduce greenhouse gas emissions from the production of iron, steel, and steel mill products. Specifically, DOE must establish a program of research, development, demonstration, and commercial application of advanced tools, technologies, and methods for low-emissions steel manufacturing. DOE, in collaboration with industry partners, institutions of higher education, and DOE's national laboratories, must also support an initiative for the demonstration of low-emissions steel manufacturing.