Olive Pit Biochar Shows Promise as Low-Carbon Alternative in Concrete Production

By Daniel Dawson

Jan. 7, 2026 14:58 UTC

Summary

Researchers from the Polytechnic University of Catalonia found that replacing natural sand in concrete with biochar from olive pits can reduce the carbon footprint of concrete production. Chatham House reports that changes in cement production are urgently needed to reduce global carbon dioxide emissions in line with the Paris Agreement on climate change.

Researchers from the Polytechnic University of Catalonia said early tests show promising results when replacing part of the natural sand used in concrete with biochar produced from olive pits.

According to the London-based think tank Chatham House, cement production — the main ingredient in concrete — accounts for approximately eight percent of global carbon dioxide emissions.

The process of transforming limestone, often in the form of sand, into aggregate for concrete production also releases carbon dioxide into the atmosphere.

Fossil fuels are additionally required to generate the high temperatures needed for this transformation, further contributing to greenhouse gas emissions.

“Significant changes in how cement and concrete are produced and used are urgently needed to achieve deep cuts in emissions in line with the Paris Agreement on climate change,” Chatham House wrote.

To that end, the Polytechnic University of Catalonia research group said incorporating biochar reduced the carbon footprint of concrete production while delivering promising mechanical performance and improved resistance to water penetration.

Unlike limestone sand, biochar does not release carbon during concrete production. The researchers also noted that a “significant amount” of carbon dioxide is captured and stored in biochar that would otherwise return to the atmosphere if olive pits were left to decompose or burned.

“Considering that concrete is the second most consumed material in the world after water, incorporating biochar into the construction of future buildings would represent a major step forward in sustainability,” said Alvaro Espuny, chief executive of Carboliva, which supplied the biochar used in the study.

Carboliva said it produces biochar from olive pits through a controlled pyrolysis process conducted in the absence of oxygen.

“This prevents the carbon in the pits from converting into carbon dioxide and being released into the atmosphere; instead, the carbon is fixed in a solid and stable structure,” the company wrote. “By integrating the biochar into concrete, buildings could effectively become carbon storage facilities.”

The company added that the carbon dioxide absorbed by olive trees during their life cycle would remain trapped within the structure of the finished building materials.

Beyond concrete, Carboliva and the Polytechnic University of Catalonia are also exploring the use of biochar in asphalt binders, which both organizations said could significantly reduce emissions associated with road construction.

The university’s research into olive pits as a building material is not new.

A 2024 study from another Spanish university found that incorporating ground olive pits in mortar used for bricks reduced thermal conductivity, lowering the energy required to heat and cool buildings.

Olive pits have also been used as a renewable energy source. A 2021 study demonstrated that they offer the highest calorific yield among comparable biofuels while maintaining a lower environmental impact.

Due to their high energy density, olive pits are already being used as an ingredient in aviation biofuel at Seville’s airport and to power a tourist train that carries visitors through the vineyards and olive groves of Provence in southern France.

Olive Pit Biochar Shows Promise as Low-Carbon Alternative in Concrete Production

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