The California legislature has a big opportunity to cut greenhouse gas emissions from one of the world’s most carbon-intensive products—concrete—by passing Senate Bill 778 authored by Senator Josh Becker. The bill would add concrete to the Buy Clean California Act, which requires the state to use low-carbon building materials in public works projects.
Following on the 2021 passage of SB 596, which mandated a roadmap for net-zero GHG emissions associated with cement by 2045, SB 778 would leverage the state’s considerable purchasing power to accelerate the large-scale development of low-carbon concrete. It would continue the momentum of overall low-carbon state procurement since the enactment of the Buy Clean California Act in 2018.
Concrete is the world’s most widely used building material and one of its fastest growing, due to voracious demand for new buildings and infrastructure in China, India, and other high growth economies. The manufacturing of cement, the key ingredient in concrete, produces nearly 8% of all global CO2 emissions. If the cement industry were a country, it would emit more GHGs than any other nation besides China, the U.S., and India.
In California, cement production accounts for about 2% of GHG emissions—the state’s second-largest industrial emitter after oil and gas production—and the state’s market is projected to grow by as much as 40% by 2040. It’s critical that we address this sector to both meet our aggressive emission reduction goals and, as California has done on many other fronts in the battle against climate change, to serve as a global model for climate action. As the world’s fifth-largest economy, the state’s power of the purse is a potent tool.
The Biden Administration has already acted to reduce emissions from concrete. In late March, the General Services Administration (GSA) announced it will immediately require federal contractors to use low-carbon concrete (as well as asphalt) in the agency’s major projects. This includes projects funded through the bipartisan infrastructure bill, such as $3.4 billion to modernize 26 land ports of entry along the U.S. borders with Canada and Mexico. The GSA oversees a whopping $75 billion in federal contracts annually.
California needs to jump on board. SB 778 is sponsored by NRDC and supported by a variety of environmental and business organizations including The Climate Center, the American Institute of Architects CA, Graniterock, the California Construction and Industrial Materials Association, Union of Concerned Scientists, SF Bay Physicians for Social Responsibility, and Environmental Entrepreneurs (E2), to name a few. The bill would:
- Require prospective state contractors to disclose the embodied GHG emissions in concrete;
- Provide incentives for leading-edge, low-carbon concrete manufacturing technologies;
- Set minimum standards to align concrete purchasing with the state’s climate goals; and
- Change currently outdated content specifications to performance specifications.
The last provision is critical. Under decades-old specifications still in place, minimum amounts of Portland cement, by far the most carbon-intensive ingredient of concrete, are routinely still required as proxies for strength and durability criteria. The production of cement accounts for 80-90% of concrete’s embedded GHG emissions. But modern alternatives, such as Portland limestone cement (PLC), limestone calcined clay cement (LC3) and supplementary cementitious materials, such as natural pozzolans, can match or exceed the performance of Portland cement. By switching from content to performance requirements, a lower carbon-footprint (and often lower-cost) concrete mix can be used. Caltrans, the UC-Davis campus, and cities including Berkeley, Davis, and Los Gatos have already made this switch.
The Buy Clean California Act requires bidders on state contracts to submit Environmental Product Declarations (EPDs) on many building materials such as carbon steel rebar, structural steel, flat glass, and mineral wool board insulation. But concrete was not included in the original framework, in part because it is considered a “hard to abate” material. This stems from the fact that the chemical process to create cement—heating powdered limestone in a rotary kiln—accounts for the majority of GHGs in concrete production, rather than the electricity consumed to power the process. A cleaner energy mix doesn’t significantly reduce concrete’s carbon footprint; the cement component needs to be reduced or supplanted by the lower-carbon cement alternatives described above.
SB 778 would create strong market signals for the cement industry to reduce its carbon intensity, and California cement manufacturers have committed to carbon neutrality by 2045. The new GSA mandate for federal projects shows where the concrete industry is headed, and it’s time for California to show its climate action leadership in this critical piece of low-carbon infrastructure. The legislature should add concrete to the Buy Clean program and pass SB 778 as soon as possible.