Decarbonizing aluminum production: Integrating high-temperature modular nuclear reactors for sustainable energy supply

• Aluminum production is among the most energy- and emissions-intensive industries. • Hydropower smelting is low-carbon but geographically limited and logistics-intensive. • HTGRs provide reliable electricity and high-quality heat for aluminum electrolysis. • Life-cycle assessment shows HTGR colocation integration with aluminum production can cut CO 2 emissions by up to 53 %. • Nuclear-powered smelting offers policy, trade, and energy security advantages. Aluminum is indispensable to modern infrastructure, transportation, and manufacturing, with applications ranging from airplanes and electric vehicles to beverage cans and solar panels. As global demand accelerates with electrification and lightweight design, aluminum production remains one of the most energy- and emissions-intensive industrial processes. The smelting stage alone consumes vast amounts of electricity and drives significant greenhouse gas (GHG) emissions. While hydropower has historically supplied relatively low-carbon energy for smelters, it is geographically constrained, increasingly vulnerable to climate variability, and insufficient to meet future growth. Achieving ambitious decarbonization targets requires scalable, reliable, and low-carbon alternatives. This study investigates high-temperature gas-cooled small modular reactors (SMRs) as a transformative pathway. These advanced nuclear systems can supply both heat and electricity, be deployed modularly near industrial sites, and offer strong safety and efficiency advantages. Co-locating SMRs with smelters reduces emissions from power generation while minimizing transmission losses and grid dependence. A life-cycle assessment (LCA) using GREET indicates that SMR integration could cut U.S. aluminum-related CO 2 emissions by up to 5.62 million tonnes annually, while lowering carbon footprint and acidification potentials by ∼70 % and ∼22 %, respectively. These findings underscore nuclear energy’s potential to provide a scalable, sustainable pathway for decarbonizing one of the world’s most energy-intensive industries.