California Air Resources Board

To the California Air Resources Board,
On behalf of Furno, a California-based startup developing a novel kiln technology for decarbonized cement production, we appreciate the opportunity to provide comment on the Draft Net-Zero Greenhouse Gas Emissions Strategy for the California Cement Sector.
We commend CARB for its leadership in tackling emissions from one of the hardest-to-abate sectors and support the SB 596 strategy’s ambition to achieve a 40% reduction in GHG intensity by 2035 and net-zero emissions by 2045. We write to offer technical insight into how emerging kiln technologies like ours can contribute to this transition in the near term while delivering co-benefits in circularity, local supply resilience, and economic development.
Furno is a proud member of the Decarbonized Cement and Concrete Alliance (DC2), a coalition of companies working to bring deeply decarbonized cement and concrete technologies to market. We strongly support the comments submitted by DC2, particularly regarding the critical role of advance procurement commitments and the urgent need to create durable demand signals that enable capital deployment into next-generation infrastructure.
Our comment is offered in addition to the DC2 submission, to highlight how one such next-generation technology — a modular, high-efficiency kiln system developed by Furno — can enable deep emissions reductions, circularity, and localized production aligned with the strategy’s goals.

About Furno's Technology
Furno is developing a new clinker production process in South San Francisco, California that unlocks modular, circular, and efficient cement production. Put simply, Furno’s micro kilns can be deployed at concrete producer sites, can take a variety of inputs including waste streams of recycled building materials, and can produce Ordinary Portland Cement (OPC) with half of the CO2 and almost none of the particulate matter of a typical cement kiln. Furno achieves these targets without hydrogen or CCS, although our kilns are compatible with these technologies.
While Furno’s OPC will be cost-competitive with traditional non-decarbonized cement, the kiln’s modularity reduces capital expenditures and roll-out times by orders of magnitude compared to previous industrial solutions. To enable this, Furno pioneered a new combustion process and kiln design, thus building on decades of research to achieve unprecedented efficiency. Furno’s novel technology unlocks the introduction of both low-carbon fuels and alternative feedstocks, whereas the large-scale and inflexibility of traditional rotary kilns hinder the transition away from carbon-intensive materials.
Specifically, Furno’s gas-fired process reduces CO2e emissions by 47%, and hazardous emissions of SO2, NOx, CO, VOCs, and fuel particulate matter by over 90% compared to the US baseline for a traditional cement kiln. By transitioning from natural gas to hydrogen or biogases, Furno has developed a long-term path to achieve over 80% reduction in carbon intensity and even higher elimination of particulate matter, still without relying on CCS. Furno’s technology therefore represents a near-term opportunity to produce green cement, reduce supply challenges for concrete producers, and help California achieve ambitious emissions and air quality goals.

Furno’s technology has so far been demonstrated at pilot scale in an industrially relevant environment (TRL level of 6). With offtake and supply agreements in place, coupled with selling a proven product into an existing market, Furno’s cement is at an Adoption Readiness Level of 8. Furno aims to deploy its first commercial installation in 2027.

Furno’s cement kiln compared to a traditional kiln 
Alignment with SB 596 Goals
Furno’s solution directly supports key pillars of the SB 596 Strategy:
A. Reduces Clinker-Related Emissions at the Source
By redesigning the kiln process and unlocking circularity, Furno reduces both combustion and process emissions associated with clinker production — which accounts for 90% of cement-related emissions. Our system reduces embodied carbon by enabling the use of alternative cement feedstocks and supplementary materials.
B. Supports Circularity and Waste Stream Utilization
Furno’s process is uniquely compatible with a variety of feedstocks, including industrial byproducts and recycled materials. This promotes circularity in the built environment and aligns with California’s SB 1383 waste reduction goals.
C. Enables Distributed, Resilient Cement Supply
California currently imports significant volumes of cement, particularly into the Bay Area and Central Valley, due to a lack of nearby production. Furno’s modular kilns can be deployed at or near existing concrete plants, reducing transportation emissions and strengthening local supply chains. This has added value for Caltrans and state construction projects, especially as Buy Clean procurement standards evolve. Thanks to its clean kiln design, Furno’s systems unlock distributed cement supply with very limited impact on local air quality.
D. Offers a Near-Term, Scalable Decarbonization Pathway
High capital expenditures and extended deployment times have long limited innovation in the cement industry. Many decarbonization technologies thus remain years away from commercial readiness, while Furno offers a deployable solution that can make an impact in this decade. Our modular, flexible architecture allows for incremental adoption and retrofit without waiting for major plant overhauls or new CCUS infrastructure. In addition, Furno’s technology has the potential to serve as a low-cost platform to support other technology solutions in the cement space across the innovation valley of death. Alternative cement chemistries can be more easily scaled using Furno’s modular kiln, which requires a far smaller capital investment than the multiple billions required for a traditional scale of cement kiln.

 
Policy Recommendations
To fully realize the benefits of emerging kiln technologies, we encourage CARB to:
1. Support distributed kiln solutions through demonstration funding, EPD-based incentives, and fast-track permitting pathways.
2. Include modular kiln technologies as a recognized lever in SB 596 implementation (currently absent from the decarbonization levers figure).
3. Expand Caltrans and DGS material approval processes to explicitly include cement from non-traditional production systems that meet ASTM C150 standards.
4. Prioritize funding for low-capex, near-term solutions in addition to long-lead CCUS and hydrogen pathways.
5. Emphasize the importance of circularity in cement decarbonization across the state, and provide additional incentives for solutions which can leverage waste streams.

We appreciate the opportunity to contribute to this critical effort. Cement decarbonization will require multiple pathways, and we believe distributed, low-emissions kiln technologies can play a vital and complementary role in achieving California’s climate and air quality goals. We welcome continued engagement with CARB and other agencies to refine technical standards, demonstration pathways, and procurement frameworks.

Sincerely,

Mandeep Arora, MS Gurinder Nagra, MS
President Founder & CEO
Furno Materials Furno Materials
mandeep@furno.com gurinder@furno.com