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California considers ambitious bills to rein in carbon emissions from concrete

Experts say concrete could be much cleaner, but the policy to make it so is missing. State lawmakers want to change that.

Ingrid Lobet
Ingrid Lobet
5 min read
California considers ambitious bills to rein in carbon emissions from concrete

In California, two bills working their way through the state legislature could soon become the most far-reaching laws in the country to address concrete’s greenhouse gas footprint.

Concrete is responsible for 7 to 8 percent of all carbon dioxide emissions globally, making it a critical target for states and countries trying to squeeze greenhouse gas emissions out of their industrial and building sectors.

New York, New Jersey and Colorado have brought forward legislation to tackle this challenge. But California’s two bills would go beyond what other states have passed so far in requiring carbon reductions.

“We have solutions, but they have not been deployed at scale,” said Sen. Josh Becker (D), a first-term California state senator with a background in venture capital, who authored the two bills.

Cutting the carbon footprint of cement over the long haul

The first, SB 596, would reduce the amount of carbon associated with the production of cement by 40 percent by the end of 2035. Cement is the most carbon-intensive ingredient of concrete. The bill passed out of a key committee in the California legislature last week, with all three Republican committee members voting in favor, for a unanimous vote of 11-0.

Republican assembly member Heath Flora, who represents part of the California Central Valley, said he was excited to vote for it. “To industry: Take note, this is the pathway,” he said.

Under SB 596, regulators would create a metric to easily compare the climate impact of different types of cement.

“We support this bill and see it as being of great assistance to us in meeting our carbon-neutrality goals for 2045,” said Tom Tietz, executive director of the California Nevada Cement Association, who worked closely with Becker on the language.

Emissions from California plants making cement are down by 17 percent since 2000. But they have risen in seven of the last nine years, largely tracking economic growth, at a time when all emissions need to be on a steep path to zero. Even at current levels of atmospheric carbon, people are getting smoked out of their homes from wildfire and flooded out by climate-change-intensified storms.

At the same time, state-level laws must contend with the fact that cement is a globally traded commodity, Tietz said, meaning that sales could easily shift to Asia. Those crafting the bill, including Becker and the Natural Resources Defense Council (NRDC), shared that concern.

To account for this, the bill imposes carbon limits on cement regardless of where it comes from, allowing the California Air Resources Board to create a “border adjustment carbon mechanism.” Becker said that the members of the legal staff are confident that the language can withstand a challenge under World Trade Organization rules, created to prevent members from privileging their own domestic products.

“California cement plants haven’t had to do much yet” when it comes to reducing carbon, said Alex Jackson, a senior attorney in NRDC’s climate and clean energy program, who worked on the bill. One of the strengths of SB 596 is that it allows the state’s Air Resources Board to set hard limits on cement, as well as interim targets. “They are enforceable. This is not aspirational,” he said.

At the same time, Jackson stressed that a companion piece of legislation will add key accountability measures to California’s push to decarbonize its concrete.

A "buy clean" concrete law for California public contracts

The second bill, SB 778, faces a stiffer headwind, Jackson said. The “buy clean” law would change the public contracting code so that when the state creates a contract for a building or a roadway, it would select bidders that commit to using less carbon-intensive concrete.

Governments are the largest purchasers of concrete and thus “have the most power over a concrete producer to change behavior,” said Eric Dunford, senior director for government affairs at CarbonCure. The company has a technology that permanently locks carbon dioxide into concrete through mineralization, lowering its net impact on the climate.

Under SB 778, beginning in the summer of 2022, any contractor who successfully wins a state contract would have to spell out how dirty their concrete is using a document known as an Environmental Product Declaration. By 2023, bidders would have to submit the paperwork together with their bid, and it would have to include emissions from delivery to the worksite. By 2024, the state could apply a 5 percent preference to any contractor bidding the job using low-carbon concrete, effectively a 5 percent discount from that bid to make it more competitive. Contractors who make use of a “breakthrough technology” could gain an additional 3 percent preference.

The bill, which will face a hearing in a legislative committee on Wednesday, has relief valves for industry. There’s an off-ramp if the rules would lead to only a single bidder or a significant delay. When the state sets the average, it could exclude super-low-carbon concrete if it costs much more than the alternatives.

If passed, SB 778 could go a significant way toward eliminating a widely understood but wasteful practice in the concrete sector: In each step along the design and construction process, a little bit of cement is added to the concrete mix. Industry experts say this informal practice is a commonly used method to boost the strength of the final product, even though the original specifications for the material were written by a qualified engineer. When applied across the industry, this has become a major source of additional carbon intensity for concrete.

Bruce King, a structural engineer for 40 years and author of books on low-carbon architecture, said he recently tried to specify 2,500-pounds-per-square-inch (psi) concrete for a house he’s building in California’s wine country. The concrete plant came back with a mix that was heavy on cement and exceeded his psi specifications.

“The mindset is very entrenched and is very hard to change,” he said. But steep reductions in carbon from concrete are entirely doable if stakeholders and industry players would address this issue, he said.

Efforts to rein in carbon emissions from the concrete sector are also moving forward outside California. Portland, Oregon is paying concrete contractors to track how much carbon is released in the making of their concrete so that the city can establish a baseline. New York lawmakers recently passed a bill that will task a state agency with studying the potential to implement public contracting preferences and carbon accounting standards similar to those in the California bills. The bill will now move to the governor’s desk.

The New Jersey legislature, which stays in session through December, is considering a clean concrete bill. In Colorado, there’s an effort to mandate carbon disclosure on concrete, a first step to toward a preference.

“The idea is starting to spread,” CarbonCure’s Dunford said.

(Article image courtesy of Leo Fosdal)

carbon emissionsconcretecementindustrial emissionsbuilding decarbonization

Ingrid Lobet

Ingrid Lobet currently divides her time between reporting on climate solutions and investigative work on climate, energy and environmental health.