ACEEE submitted comments in response to the California Market Transformation Administrator’s Request for Ideas on low embodied carbon concrete technologies, which can lower energy use and reduce greenhouse gas (GHG) emissions through widespread adoption in the state. ACEEE’s comments focused on how emerging technologies like calcined clays may achieve broad market acceptance by overcoming market adoption barriers. The comments describe how material efficiency through the use of calcined clays as a supplementary cementitious material (SCM) can be combined with energy efficiency for energy and GHG reductions leading to the greatest impact through energy savings, decarbonization, and community benefits, while advancing equity, affordability, and workforce development.