The Carbon Footprint of Traditional Construction Materials

Cement and steel are two of the most carbon-intensive materials on Earth, together accounting for roughly 15% of global CO₂ emissions. Cement production alone contributes around 7% of total emissions due to the calcination process (releasing CO₂ from limestone) and the high-temperature kilns fueled by fossil energy. Steel manufacturing, meanwhile, involves blast furnaces that rely heavily on coal.

When applied to energy infrastructure, these materials form the backbone of foundations, towers, and transmission systems. A single utility-scale wind turbine, for instance, can contain up to 500 tons of steel and require massive concrete bases. The embodied carbon from such materials can amount to several thousand metric tons of CO₂ per project, even before the first kilowatt-hour is generated.

Emerging Low-Carbon Alternatives

To mitigate these emissions, researchers and industry innovators are developing and deploying low-carbon versions of cement and steel:

• Low-Carbon Cement: Options include supplementary cementitious materials (SCMs) like fly ash, slag, and calcined clay, which reduce clinker content. CarbonCure and Solidia are two companies pioneering CO₂-injected concrete, which permanently stores CO₂ during curing.
• Green Steel: Hydrogen-based direct reduction (H-DRI) replaces coke with green hydrogen as the reducing agent. Leading firms like SSAB in Sweden and H2 Green Steel are scaling up commercial production.

Additionally, recycled steel from electric arc furnaces (EAFs) powered by renewable energy can offer significant emission reductions compared to traditional methods.

Policy and Market Drivers

The rise of low-carbon building materials is not only technology-driven but also policy-enabled. The U.S. Inflation Reduction Act (IRA) includes funding to support clean industrial processes, while Buy Clean initiatives at state and federal levels incentivize the use of low-embodied-carbon materials in public projects.

Investors and developers are also applying pressure through:

• ESG benchmarks that factor in embodied emissions
• Green bonds and sustainable finance instruments that require lifecycle assessments
• Corporate Scope 3 targets that extend to construction and capital goods

Forward-thinking clean energy developers are integrating material-level carbon analysis into procurement, not just as a compliance issue but as a competitive differentiator.

Practical Steps for Project Developers

To integrate low-carbon materials into clean energy projects, companies can take several practical actions:

1. Conduct Embodied Carbon Assessments Early: Use LCA tools (like One Click LCA or Tally) during project design to evaluate material impacts.
2. Source Certified Low-Carbon Materials: Look for EPDs (Environmental Product Declarations) and engage with suppliers offering third-party-certified products.
3. Incorporate into Procurement RFPs: Include embodied carbon criteria in vendor selection for concrete, steel, and structural components.
4. Engage with Material Innovators: Partner with startups and suppliers testing new formulations or recycled-content materials.
5. Track and Report: Include material emissions in sustainability disclosures and ESG reports.

These measures can support both climate commitments and cost efficiency, especially as green building standards increasingly reward embodied carbon reductions.

Conclusion

Clean energy infrastructure must be truly clean—not only in the power it generates but also in the way it is built. Cement and steel are central to this transformation. By prioritizing low-carbon alternatives and embedding material choices into ESG strategies, project developers and investors can drive real, scalable climate impact.

The shift from green to truly clean starts with recognizing that the sustainability of energy systems extends well beyond operational emissions. It begins with the first concrete pour and steel beam.

References

• International Energy Agency (IEA), "Cement – Analysis", https://www.iea.org/reports/cement
• International Energy Agency (IEA), "Iron and Steel – Analysis", https://www.iea.org/reports/iron-and-steel
• Global Cement and Concrete Association (GCCA), “Concrete Future: The GCCA 2050 Cement and Concrete Industry Roadmap for Net Zero Concrete,” https://gccassociation.org/concretefuture/
• SSAB, “Fossil-free steel production,” https://www.ssab.com/fossil-free-steel
• CarbonCure Technologies, “CarbonCure’s Technology,” https://www.carboncure.com
• Solidia Technologies, “Sustainable Cement and Concrete Solutions,” https://www.solidiatech.com
• World Green Building Council (WGBC), “Bringing Embodied Carbon Upfront,” https://www.worldgbc.org/embodied-carbon
• U.S. Inflation Reduction Act (IRA), Summary from White House, https://www.whitehouse.gov/briefing-room/statements-releases/2022/08/16/by-the-numbers-the-inflation-reduction-act/
• Building Transparency, EC3 Tool, https://www.buildingtransparency.org