A Photosynthetic Route to Carbon-Negative Portland Limestone Cement

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Boulder, Colorado
Project Term:
09/29/2022 - 09/28/2025

Technology Description:

The University of Colorado Boulder will manufacture and commercialize a net-CO2-storing portland limestone cement using biogenic limestone (CaCO3) produced via photosynthesis that will store more than 275 kgCO2 and cost less than $100 per ton of cement. Most cement-related CO2 emissions are caused by heating CaCO3 to produce calcium oxide (quicklime), which releases CO2 in the process. The proposed technology will produce biogenic CaCO3 using calcifying microalgae that sequester and store CO2 in mineral form through biological direct air capture via photosynthesis and calcification. Using this CaCO3 in biogenic cement production leads to a net carbon neutral carbon cycle.

Potential Impact:

HESTIA projects will facilitate the use of carbon storing materials in building construction to achieve net carbon negativity by optimizing material chemistries and matrices, manufacturing, and whole-building designs in a cost-effective manner.


HESTIA technologies will reduce the carbon footprint of the built environment.


Building materials and designs developed under HESTIA will draw down and store CO2 from the atmosphere.


A variety of promising carbon storing materials are being explored and commercialized for building construction. Currently these materials are generally scarcer, cost more per unit, and/or face performance challenges (e.g., flame resistance for biogenic carbon-containing materials). HESTIA seeks technologies that overcome these barriers while nullifying associated emissions and increasing the total amount of carbon stored in the finished product.


ARPA-E Program Director:
Dr. Laurent Pilon
Project Contact:
Prof. Wil Srubar
Press and General Inquiries Email:
Project Contact Email:


National Renewable Energy Laboratory
University of North Carolina at Wilmington

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