Fortera lands $85M to scale up low-carbon cement

Cement is one of the most widely used materials in the world, but making it causes a lot of planet-warming carbon emissions. The industry is responsible for roughly 8 percent of global emissions, most of which are not from burning fossil fuels but a byproduct of the high-temperature chemical reaction used to create an important cement precursor.

Ryan Gilliam, CEO of cement-making startup Fortera, believes his company’s approach offers the massive industry an elegant solution to these ​“process” emissions: putting the CO₂ right back into the cement itself. On Tuesday, the San Jose, California–based startup announced an $85 million Series C funding round that Fortera plans to use to help bring its technology to production scale.

In April, Fortera started making its product at a test facility it built alongside a cement plant owned by partner CalPortland in Redding, California. Massive kilns from CalPortland use high temperatures to convert limestone — calcium carbonate — into the cement precursor calcium oxide. The carbon dioxide emitted by this process is then piped into reactors within Fortera’s facility and chemically bonded with a form of ​“reactive carbonates” that Fortera produces from calcium carbonate via a proprietary process. After further refinement, these CO₂-infused carbonates become Fortera’s ReAct cement.

By capturing and using the carbon that would otherwise have been vented into the atmosphere, Fortera’s product emits 70 percent less CO₂ than industry-standard ordinary Portland cement, Gilliam told Canary Media. If combined with clean energy, emissions from the cement-making process can be slashed even further, he said, to ​“zero percent on the kiln side.”

Not only is the cement cleaner, but the production method is more efficient, Gilliam said. Carbon constitutes about 44 percent of the weight of the limestone that goes into cement-making kilns. In the traditional cement-making process, that weight is lost to the atmosphere. By re-embedding that carbon into its reactive carbonates, Fortera is ​“almost doubling the amount of product for each ton [of limestone] we process,” he said.

That doubling of production capacity could allow cement plants using Fortera’s technology to ​“sell at a competitive cost with cement,” he said — if the technology can be applied at the massive scale needed for cement plants to be profitable.

“The Redding plant shows that this can scale, that the project works,” Gilliam said. But the project is currently producing only about 15,000 tons per year, far less than the 1 million tons per year made by a standard plant. To get to the scale necessary to compete in the cement industry, Fortera has ​“a significant number of projects” under development, each in the $150 million to $200 million range, he said.

The new funding round, led by previous investors Khosla Ventures and Temasek and including new investors Wollemi Capital, NOVA by Saint-Gobain, Presidio Ventures, and Alumni Ventures, will provide the money Fortera needs to bring those larger-scale projects to the point where they can secure lower-cost project-financing capital.

Projects at that scale need a lot of ​“front-end development work and financing,” he said, ​“from the permitting side, to doing fee packages on the engineering to get the actual capital costs locked down, and getting utilities and that sort of thing worked out. This $85 million is allowing us to get project-financing dollars to work and get these projects started.”

The long road to cutting cement’s carbon emissions

Decarbonizing the $15 billion-per-year global cement industry will be costly and challenging. In a 2023 report, the U.S. Department of Energy estimated that roughly one-third of the industry’s emissions can be eliminated with well-established methods, such as using supplementary cementing materials to displace between 30 and 45 percent of carbon-intensive clinker — the core precursor material for cement — used in ordinary Portland cement.

But the remaining two-thirds of cement emissions will be much harder to tackle. One hurdle is the cost: Doing so could require a cumulative $5 billion to $20 billion of investments by 2030 and from $60 billion to $120 billion by 2050 in the U.S. alone, DOE reported.

To make things more complicated, cement manufacturers have a bewildering array of choices ahead to achieve this deeper decarbonization — none of which has yet been proved at scale. Should they keep using current cement facilities and feedstocks and focus on reducing or capturing emissions? Or should they switch to novel feedstocks and production processes that offer significant emissions reductions up front?

Cement producers that want to mitigate emissions from their existing facilities can replace fossil fuels used to heat cement kilns with carbon-neutral biomass or waste — or potentially low-carbon hydrogen. They can also capture and store carbon emissions underground, as is being proposed for fossil-fueled power plants and from the budding carbon-removal industry.

Many of the world’s largest cement manufacturers, such as Cemex, Heidelberg Materials, and Holcim, are working on these options, in some cases with government support. But it’s far from clear whether carbon capture and storage is a technically and financially viable option for an industry that competes globally on very tight profit margins.

Meanwhile, a variety of startups and government- and university-backed researchers are working on new low-carbon methods that could replace the centuries-old cement-making process.

Startups like Brimstone Energy replace limestone with other minerals that don’t have carbon. An approach being pursued by startups such as Sublime Systems is to replace high-temperature kilns with electricity-powered cement production methods. Both of these companies recently won DOE grants to build commercial-scale production facilities as part of a series of industrial-decarbonization awards that also included grants for carbon capture, alternative fuels, and supplementary cement material production.

The challenge with these alternative pathways is that they will require cement producers to change how they source their precursor materials or rebuild production facilities at the billion-dollar scale of today’s cement plants, Gilliam said. Though Fortera is pursuing a novel process, its model ​“is leveraging as much of the existing feedstocks and capital infrastructure that we can,” he said.

And while Fortera’s process does require cement manufacturers to invest in the firm’s carbon-capture technology, Gillam claims those costs can be recovered through the increased production capacity achieved by embedding that carbon into its finished product. That’s in contrast to conventional carbon capture and storage, where ​“you’re adding all that capital cost and pumping it underground for no value.”

Fortera isn’t alone in taking this approach. Companies such as CarbonCure, CarbonBuilt, and Solidia inject CO₂ into concrete as it’s poured or formed into precast shapes. Startup Carbon Upcycling is chemically activating coal power plants’ fly ash and steel mills’ slag, two commonly used cement supplements, to bind with CO₂ that’s captured at cement manufacturing sites.

From test pours to mass markets

Another key barrier for novel low-carbon cement startups is getting buyers to embrace changes to a safe and reliable recipe that’s been in use since the 1800s. New products in the cement and concrete world can take up to or more than a decade to move from initial tests to wider adoption, per DOE’s report from last year.

On that front, Fortera has won a vote of confidence from ASTM International, a key standards body, Gilliam said. Earlier this summer, ASTM published guidance affirming that mineralized calcium carbonate of the type Fortera produces is acceptable along with natural limestone as an input into the cement it certifies.

“ASTM has 160 members, and you have to get a unanimous vote” for standards changes of this type, he said. ​“That was credibility in the concrete world seeing us test our product.”

Standards certifications of this kind are only a first step in convincing the ready-mix concrete providers, construction companies, and government agencies that make up the biggest users of cement that they should buy a newly introduced product.

Fortera expects to announce in the next month or two the first commercial buyers of its ReAct product from its Redding facility. The startup is working to establish commercial relationships with concrete ready-mix companies in Northern California and is working with as yet undisclosed construction partners ​“to validate the product” in planned real-world projects, he said.

To start, Fortera’s cement shipments are likely to be used in concrete for sidewalks, floors, and other nonstructural purposes, he said. That’s a typical way to test novel cement and concrete formulations.

Last year, Fortera announced plans to mix its ReAct product into standard cement at 15 percent blends — a relatively common approach from makers of novel cement.

But Fortera expects to increase the proportion of its product that goes into the cement mixes it will deploy with its partners, Gilliam said.

“The holy grail for us was always to go to 100 percent material,” Gilliam said, since higher percentages of a lower-carbon product can yield greater overall carbon reductions per ton of product sold.

With the nod from ASTM, ​“we’ve shown our 100 percent material can get to performances similar to Portland cement at room temperature,” he said. ​“Roughly half the material coming out of Redding is going to go toward 100 percent use cases … that’s really getting pull from the market.”