Synhelion claims clinker milestone for solar cement

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.

Working with global cement and construction materials company Cemex, Synhelion delivered the first 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.