Low-carbon materials (cement, steel, timber) KPIs by sector (with ranges)

Global cement production alone generates roughly 8% of anthropogenic CO2 emissions, while steel manufacturing adds another 7%, yet fewer than 20% of procurement specifications in the US currently include carbon intensity thresholds for these materials. As regulations like the Buy Clean Act and the EU Carbon Border Adjustment Mechanism tighten, the ability to measure, benchmark, and reduce the carbon footprint of cement, steel, and timber is shifting from a sustainability aspiration to a procurement requirement. The KPIs organizations track determine whether low-carbon materials adoption stays at the pilot stage or becomes standard practice across portfolios.

Why It Matters

Low-carbon materials sit at the nexus of industrial decarbonization, construction procurement, and trade policy. The US federal Buy Clean Act mandates maximum carbon intensity thresholds for steel, concrete, asphalt, and flat glass in federally funded projects. California's Buy Clean California Act (AB 262) already requires Environmental Product Declarations (EPDs) for structural steel, concrete reinforcing steel, flat glass, and mineral wool insulation. The EU's CBAM, phasing in through 2026, prices the carbon content of imported cement, steel, and aluminum at the border.

For construction and infrastructure teams, these policies mean that tracking the right KPIs is no longer optional. Procurement decisions increasingly hinge on whether suppliers can demonstrate carbon intensity below specified thresholds. For manufacturers, the ability to report credible, verifiable KPIs determines market access in regulated jurisdictions. Investors screening portfolios for transition risk use material-level carbon intensity as a leading indicator of both regulatory exposure and operational efficiency.

The complexity lies in comparability. Cement carbon intensity varies by clinker factor, fuel mix, and supplementary cementitious material (SCM) blend. Steel emissions depend on whether the production route is basic oxygen furnace (BOF) or electric arc furnace (EAF), the grid carbon intensity at the mill, and the recycled content share. Timber metrics involve biogenic carbon accounting debates that can swing results by hundreds of kilograms of CO2 equivalent per cubic meter. Without sector-specific benchmark ranges, teams risk setting targets that are either unachievable or meaninglessly loose.

Key Concepts

Carbon intensity measures the greenhouse gas emissions per unit of material produced, typically expressed as kgCO2e per tonne for bulk materials or kgCO2e per cubic meter for timber. This metric enables direct comparison between suppliers and production routes within the same material category.

Environmental Product Declarations (EPDs) are standardized, third-party-verified documents reporting the environmental impact of a product across defined lifecycle stages. For construction materials, EPDs follow ISO 14025 and EN 15804 standards and serve as the primary data source for carbon intensity comparisons.

Clinker factor is the ratio of clinker to total cite in cement. Clinker production is the most carbon-intensive step in cement manufacturing, so reducing the clinker factor through substitution with fly ash, slag, calcined clay, or limestone filler is the primary lever for reducing cement carbon intensity.

Biogenic carbon refers to CO2 absorbed by trees during growth and stored in timber products. Accounting for biogenic carbon in LCA remains contentious: EN 15804:2012+A2:2019 requires separate reporting of biogenic carbon flows, but whether to credit sequestration at the product stage varies by standard and jurisdiction.

Recycled content in steel reflects the share of scrap metal in the production feedstock. EAF steelmaking uses 85-100% recycled scrap, while BOF production typically incorporates 15-35% scrap. Recycled content directly correlates with carbon intensity, making it a useful proxy metric when facility-level EPDs are unavailable.

KPI Benchmarks by Sector

KPI	Sector / Material	Low Range	Median	High Range	Unit
Cement carbon intensity	Portland cement (OPC)	750	850	950	kgCO2e/t
Cement carbon intensity	Blended cement (30% SCM)	500	600	700	kgCO2e/t
Cement carbon intensity	Low-carbon cement (50%+ SCM)	350	450	550	kgCO2e/t
Concrete carbon intensity	Standard ready-mix (30 MPa)	200	280	370	kgCO2e/m3
Concrete carbon intensity	Low-carbon ready-mix (30 MPa)	100	160	220	kgCO2e/m3
Steel carbon intensity	BOF (primary)	1,800	2,100	2,400	kgCO2e/t
Steel carbon intensity	EAF (scrap-based)	300	500	700	kgCO2e/t
Steel carbon intensity	DRI-EAF (natural gas)	900	1,100	1,400	kgCO2e/t
Steel carbon intensity	DRI-EAF (green hydrogen)	100	250	450	kgCO2e/t
Timber carbon intensity	Sawn softwood (excl. biogenic)	50	80	130	kgCO2e/m3
Timber carbon intensity	Cross-laminated timber (CLT)	100	170	250	kgCO2e/m3
Timber carbon intensity	Glulam	80	140	210	kgCO2e/m3
Recycled content	EAF steel	85%	92%	99%	% scrap
Recycled content	BOF steel	15%	25%	35%	% scrap
EPD coverage	Leading specifiers	50%	70%	90%	% by material value
Clinker factor	Global average	0.60	0.72	0.85	ratio
Carbon reduction vs. baseline	Best practice projects	20%	35%	55%	% reduction

What's Working

Buy Clean policies driving EPD adoption and carbon thresholds. The US federal Buy Clean Act and equivalent state laws in California, Colorado, New York, and Oregon are forcing suppliers to produce EPDs and meet carbon intensity limits. The General Services Administration (GSA) published its first maximum acceptable Global Warming Potential limits for concrete and steel in 2024, setting thresholds at roughly the 85th percentile of current industry performance. This approach rewards the best-performing producers without excluding most of the market. The result has been a rapid increase in EPD availability: the EC3 database now holds over 100,000 EPDs globally, with US concrete EPDs growing from 3,200 in 2021 to over 28,000 by early 2026.

Electric arc furnace steelmaking scaling in the US. EAF production now accounts for approximately 70% of US steel output, up from 60% a decade ago. Nucor, the largest US steelmaker, operates 25 EAF facilities producing steel at 300-500 kgCO2e per tonne, compared to 1,800-2,400 kgCO2e per tonne for integrated BOF mills. Steel Dynamics and Commercial Metals Company have similarly expanded EAF capacity. For procurement teams, this means genuinely low-carbon structural steel is commercially available at competitive pricing in the US market, making carbon intensity thresholds in specifications achievable without significant cost premiums.

Mass timber gaining structural code acceptance. The 2021 International Building Code (IBC) expanded allowable heights for mass timber buildings to 18 stories in certain occupancy categories. Projects like Ascent in Milwaukee (25 stories, the tallest mass timber building in the world at completion) and the T3 office series by Hines demonstrate commercial viability. CLT and glulam products deliver structural carbon intensities of 80-250 kgCO2e/m3, compared to 200-500 kgCO2e/m2 for equivalent reinforced concrete frames. The mass timber market in North America grew by approximately 35% annually between 2022 and 2025, with Structurlam, Katerra's successor operations, and Nordic Structures expanding production capacity.

What's Not Working

Global cement decarbonization stalling beyond SCM substitution. While blended cements with slag, fly ash, and calcined clay can reduce carbon intensity by 30-50%, supplies of conventional SCMs are constrained. Fly ash availability is declining as coal plants close, and blast furnace slag supply depends on primary steel production volumes that are themselves shrinking. Novel SCMs like calcined clay (LC3 technology) show promise in lab and pilot settings but represent less than 1% of global cement production. Carbon capture on cement kilns remains expensive at $60-120 per tonne of CO2, with only a handful of commercial-scale projects operational (Heidelberg Materials' Brevik CCS plant in Norway, operational since 2024, captures 400,000 tonnes of CO2 annually). The gap between aspirational 2050 net-zero roadmaps and current deployment rates remains wide.

Steel carbon intensity data inconsistency across geographies. While US EAF steel has well-documented EPDs, carbon intensity data for steel produced in China (which accounts for over 50% of global output), India, and Southeast Asia often relies on national averages rather than facility-specific measurements. A Chinese BOF mill connected to a coal-heavy grid may emit 2,200-2,800 kgCO2e per tonne, but procurement teams frequently default to generic factors that obscure this variance. The lack of harmonized international EPD requirements means that carbon intensity claims for imported steel are difficult to verify, undermining the credibility of scope 3 reporting for downstream users.

Biogenic carbon accounting inconsistencies distort timber comparisons. Some LCA tools and EPD programs credit the CO2 absorbed during tree growth as a negative emission at the product stage (A1-A3), producing results that show CLT as carbon-negative. Others follow EN 15804 conventions that report biogenic carbon separately, showing positive process emissions only. This discrepancy can swing results by 200-400 kgCO2e/m3 for timber-intensive assemblies, making it nearly impossible to compare timber proposals against concrete or steel alternatives on a consistent basis. Until major markets converge on accounting conventions, product teams face the risk of selecting materials based on methodological artifacts rather than genuine emissions differences.

Key Players

Established Leaders

• HeidelbergCement (Heidelberg Materials): World's second-largest cement producer, operating the first commercial-scale CCS plant on a cement kiln at Brevik, Norway. Committed to net-zero concrete by 2050 with a 15% clinker factor reduction achieved since 2018.
• Nucor Corporation: Largest US steelmaker and largest recycler in North America, operating 25 EAF facilities. Produces structural steel at 300-500 kgCO2e per tonne, positioning it as a leading low-carbon steel supplier.
• SSAB: Swedish steelmaker pioneering fossil-free steel production via the HYBRIT process using green hydrogen DRI. Delivered first fossil-free steel to Volvo in 2021, with commercial-scale production planned for 2026.
• Holcim: Global cement and concrete company offering ECOPact low-carbon concrete with 30-100% lower carbon footprint than standard mixes, available in 35+ markets.

Emerging Startups

• CarbonCure Technologies: Canadian company injecting captured CO2 into concrete during mixing, reducing cement content while maintaining strength. Deployed in 750+ concrete plants across North America.
• Brimstone Energy: Developing carbon-negative Portland cement using calcium silicate rock instead of limestone, eliminating process emissions from calcination. Backed by Breakthrough Energy Ventures.
• Sublime Systems: Producing low-carbon cement using an electrochemical process that replaces the traditional kiln, operating at ambient temperature and avoiding combustion emissions entirely.
• Boston Metal: Developing molten oxide electrolysis for steel production that uses electricity instead of coal, targeting near-zero-emission steel at scale.

Key Investors and Funders

• Breakthrough Energy Ventures: Investing in frontier materials decarbonization including Brimstone, Boston Metal, and CarbonCure.
• US Department of Energy (DOE): Funding industrial decarbonization through the Industrial Demonstrations Program, with over $6 billion allocated for cement, steel, and other heavy industry projects.
• Global Cement and Concrete Association (GCCA): Industry body representing 80% of global cement production, coordinating the 2050 net-zero roadmap and standardizing carbon reporting across members.

Action Checklist

1. Require EPDs for all structural materials (concrete, steel, timber) in procurement specifications, setting maximum carbon intensity thresholds aligned with GSA or Buy Clean California benchmarks.
2. Specify EAF-produced steel where structurally appropriate, targeting carbon intensity below 600 kgCO2e per tonne for reinforcing bar and structural sections.
3. Evaluate low-carbon concrete mixes (ECOPact, CarbonCure-treated, or high-SCM blends) for non-structural and moderately loaded structural applications, targeting below 200 kgCO2e/m3.
4. Establish a consistent biogenic carbon accounting policy for timber products, documenting whether biogenic credits are included or excluded and applying the same convention across all project comparisons.
5. Track EPD coverage rate as a procurement KPI, targeting 70%+ of specified materials by value having product-specific or facility-specific EPDs within 12 months.
6. Benchmark projects against sector-appropriate carbon intensity ranges (use the table above) and report results to industry databases like EC3 or the Carbon Leadership Forum.
7. Monitor regulatory developments in CBAM, Buy Clean, and state-level clean procurement laws to anticipate future threshold tightening and supply chain requirements.

FAQ

What is the difference between cement and concrete carbon intensity? Cement is the binding ingredient in concrete, typically comprising 10-15% of the mix by weight but contributing 80-90% of the carbon emissions. Concrete carbon intensity is measured per cubic meter of the complete mix (cement, aggregite, water, admixtures), while cement intensity is measured per tonne of cite alone. A standard 30 MPa concrete mix at 280 kgCO2e/m3 might use cement with an intensity of 850 kgCO2e/t. Reducing cement content through mix optimization or SCM substitution is the primary lever for lowering concrete emissions.

How much does low-carbon steel cost compared to conventional steel? US-produced EAF steel trades at parity or within 2-5% of BOF steel for most structural products, because EAF production costs are competitive in markets with affordable electricity and scrap supply. Green hydrogen DRI steel (like SSAB's HYBRIT product) currently carries a 20-30% premium, though this gap is expected to narrow as hydrogen costs decline. For most US projects, specifying low-carbon steel from domestic EAF producers does not require a significant cost premium.

Is mass timber always lower carbon than concrete or steel? Not automatically. Mass timber structures typically show lower upfront embodied carbon (80-250 kgCO2e/m3 for CLT versus 200-500 kgCO2e/m2 for concrete frames), but outcomes depend on structural design, transport distances, and biogenic carbon accounting conventions. A timber building shipped across continents may have higher transport emissions that offset material savings. Additionally, hybrid designs combining timber with concrete or steel connections often deliver the best overall carbon performance for taller buildings.

What does the Buy Clean Act require? The federal Buy Clean Act directs the GSA to set maximum acceptable Global Warming Potential limits for construction materials used in federally funded projects, initially covering concrete, steel, asphalt, and flat glass. Suppliers must provide EPDs demonstrating compliance. The GSA thresholds are set at approximately the 85th percentile of current production, meaning most domestic producers can comply but the highest-emitting facilities must improve. Several states have enacted parallel legislation with varying scopes and timelines.

How do I verify a supplier's carbon intensity claims? Request product-specific or facility-specific EPDs verified by an accredited third party (such as UL, NSF, or SCS Global Services). Cross-reference reported values against the EC3 database to check whether claims fall within expected ranges for the material type and production process. Generic or industry-average EPDs are less reliable for benchmarking because they mask facility-level variation. For imported materials, ask for documentation of the production route (BOF vs. EAF for steel, clinker factor for cement) and the grid carbon intensity at the manufacturing location.

Sources

1. Global Cement and Concrete Association. "2050 Net Zero Roadmap: Accelerating Progress Report." GCCA, 2025.
2. US General Services Administration. "Buy Clean: Maximum Acceptable Global Warming Potential Limits." GSA, 2024.
3. Building Transparency. "EC3 Database Statistics and Market Trends." Building Transparency, 2025.
4. World Steel Association. "Steel Statistical Yearbook 2025: CO2 Emissions Data." World Steel, 2025.
5. International Energy Agency. "Cement Technology Roadmap: Carbon Emissions Reductions by Lever." IEA, 2024.
6. Carbon Leadership Forum. "North American Material Baselines: Concrete and Steel." University of Washington, 2025.
7. Nucor Corporation. "2024 Sustainability Report: Carbon Intensity and EAF Production Data." Nucor, 2025.