New Law Mandates Carbon Emission Reductions from Cement

By Published On: September 28, 2021

California just took a major step toward addressing the powerful role of concrete in climate change. Governor Newsom has signed the first bill in the country focused on cutting greenhouse gas emissions from cement, the glue that holds concrete together.

Cement making in California “is the second-largest source of industrial carbon pollution after oil and gas production,” NRDC’s Senior Attorney Alex Jackson said in a blog. It is responsible for about 7% of the world’s greenhouse gas emissions, according to the World Cement Association.

SB 596 by Sen. Josh Becker (D-San Mateo) directs the California Air Resources Board to determine the 2019 emissions from cement-making (measured in carbon dioxide per ton) and reduce that by 40% by the end of 2035.

The bill passed the Assembly 74-2 Sept. 8, and passed the Senate the next day 29–9.

Becker, a first-term senator, formerly worked in venture capital. He consulted closely with the cement industry on the bill.

Tom Tietz of the California Nevada Cement Association said the main focus of those conversations was that cement is a globally-traded commodity, meaning a crackdown could lead to loss of business in the state and more imported cement. There are seven active cement producers in California. The association says it is committed to meeting California’s goal of zero carbon economy by 2045 and issued a roadmap for the industry in March.

“The bill builds on a pledge by California’s cement industry to be carbon neutral by midcentury and will identify key barriers and solutions to turn that commitment into action,” NRDC’s Jackson wrote.

China is the world’s largest cement producer, accounting for about 55% of global production, followed by India at 8%, according to the International Energy Agency.

“Buy clean” bill fizzles

A second bill by Becker, SB 778, addressed concrete more broadly. It did not pass and was turned into a two-year bill. Becker said his staff is working on the measure and plans to reintroduce it in January.

It is a “Buy Clean” bill that requires bidders on construction projects to disclose the carbon intensity. As provisions kick in over time, cleaner bids get a preference.

Lowering the climate impact of cement and concrete is a push that has been underway for years. But reductions have been modest and experts say there is still low-hanging fruit. Owners of projects, often departments of transportation, are too prescriptive when they put projects out to bid: They instruct the industry what to do and rarely specify low-carbon concrete. Experts at the Global Concrete Summit last year said it is common to see a required minimum amount of cement, or a maximum of alternatives to cement, tying the hands of providers who could lower the carbon of their bid if they had more leeway. Cement has very high embodied carbon, whereas many partial substitutes have very low embodied carbon.

“Departments of transportation and government entities are the biggest users of concrete, with infrastructure and buildings, so they have a lot of influence over specifications for concrete,” said Lionel Lemay, an executive vice president at the National Ready Mixed Concrete Association. Queries to CalTrans went unanswered.

There are startups in California such as Sioneer offering substitute materials for cement that are much lower-carbon.

Another tool that project owners could avail themselves of is longer drying time before use. Whether on buildings or freeway overpasses, concrete continues to strengthen over time. If project owners specify 56 days instead of 28, they can use less cement, get the same strength, and keep carbon out of the atmosphere.

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