Solar thermal process produces cement with no carbon dioxide emissions

In the conventional production of lime from limestone, fossil fuels are burned during the decarbonation process, resulting in a carbon dioxide byproduct. In the STEP process, solar thermal energy is used to heat the limestone as well as assist in electrolysis, producing a different chemical reaction with no carbon dioxide byproduct. Image credit: Licht, et al. ©2012 The Royal Society of Chemistry

While the largest contributor to anthropogenic greenhouse gas emissions is the power industry, the second largest is the more often overlooked cement industry, which accounts for 5-6% of all anthropogenic CO2 emissions. For every 10 kg of cement produced, the cement industry releases a full 9 kg of CO2. Since the world consumes about 3 trillion kg of cement annually, this sector has one of the highest potentials for CO2 emission reductions. But while processes are being explored to sequester the CO2 from cement production, so far no process can completely eliminate it.