The transition to a net-zero economy will be metal intensive.2 Steel is the only material critical to all low carbon technologies, including geothermal, hydro, nuclear, bio energy, electricity networks, and electric vehicles, making it essential to the U.S. decarbonization strategy, national and economic security, and critical infrastructure.With many green advantages over other materials, metal can reduce energy consumption, improve air quality and thermal comfort, help comply with energy codes, minimize environmental impacts, and get recycled indefinitely. The CODE Building, Charlottesville, Va.
Selecting to avoid embodied carbon means adhering to the principles of reuse, reduce, and sequester. While certain natural materials, like wood, may appear to have a more favorable CO2e profile, this can be misleading as all impacts, not just GWP, should be considered in responsible material selection. It is also important to consider the effect of service life on this analysis. A structure which lasts half as long as another actually should be considered as having twice the impact for comparison purposes. With many green advantages over other materials, metal can reduce energy consumption, improve air quality and thermal comfort, help comply with energy codes, minimize environmental impacts, and get recycled indefinitely. A key step to avoiding embodied carbon is reuse. Metal is the only known construction material that can be recycled indefinitely with little impact on material properties. This allows it to be repurposed in the same exact form, a process called closed-loop recycling. Not only are excess and scrap metals such as steel and aluminum readily and easily recyclable, it remains financially viable to do so. This ensures the envisioned impact reduction will actually happen, instead of only existing “on paper.” Sixty to 80 million tons of steel scrap is recycled each year into new steel products in the U.S. alone. This impacts the cradle to cradle profile of steel. First introduced in 2002 by architect William McDonough and chemist Michael Braungart, cradle to cradle refers to design standards for creating products that model a view of natural materials as nutrients, circulating in healthy, safe metabolisms. McDonough and Braungart present an integration of design and science in Cradle to Cradle: Remaking the Way We Make Things that provides enduring benefits for society from safe materials, water, and energy in circular economies and eliminates the concept of waste. Metal meets these requirements.