Synhelion claims clinker milestone for solar cement

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Swiss energy company Synhelion has claimed another milestone in its efforts to deliver zero carbon cement, producing clinker continuously using only concentrated solar heat.

Close-up of Synhelion’s receiver delivering the high-temperature solar process heat beyond 1500°C.
Close-up of Synhelion’s receiver delivering the high-temperature solar process heat beyond 1500°C. -Synhelion

The ETH Zurich spinout uses concentrated solar thermal (CST) energy to deliver industrial heat, reaching temperatures in excess of 1500°C. While its primary focus so far for CST has been solar fuels to help decarbonise sectors such as aviation, it has also been exploring other applications, including cement production.

Clinker is produced by fusing limestone, clay, and other materials in a rotary kiln at temperatures approaching 1,500°C. The fossil fuels generally used to heat the kiln are responsible for approximately 40 per cent of the direct CO2 emissions of the process. Replacing fossil fuels with solar energy will not fully decarbonise cement production, but it can significantly reduce its environmental impact.

与全球水泥和建筑马特里工作als company Cemex, Synhelion delivered thefirst solar clinker in February 2022. Now it has announced that the technology has progressed to ‘industrially-viable levels’, including the continuous production of clinker with solar heat. Synhelion and Cemex say they will now take further steps towards building a solar-driven industrial-scale pilot cement plant.

“This is an exciting milestone for everyone involved, achieved through the excellent collaboration between the teams of Cemex and Synhelion,” said Gianluca Ambrosetti, co-founder and co-CEO at Synhelion. “Our technology can make an important contribution toward decarbonising cement production, and we look forward to more trailblazing achievements in this field.”

In February 2023, Cemex, Synhelion and Sandia National Laboratories wereawarded $3.2m by the US Department of Energy to advance CST for low carbon cement. Solar MEAD saw the partners exploring the conditions to maximize heat transfer to the raw cement mix and improve the efficiency of clinker production using CST.

“I am convinced we are getting closer to the technologies that will enable net-zero CO2cement and concrete production,” said Fernando A González, Cemex CEO. “The solid progress I see here proves that solar cement is not just a dream; it is achievable through continued collaboration and backed up by rigorous research and testing.”