Municipal solid waste is the third-largest source of methane emissions in the US, but Colorado School of Mines Assistant Professor Lori Tunstall aims to turn this problem into a climate solution.
Tunstall received $1 million from the Gordon and Betty Moore Foundation to explore how municipal waste can be converted into biochar to replace cement in concrete. Cement is the second-largest industrial source of CO2 emissions in concrete building materials.
Her patent-pending jet-black concrete, which replaces up to 50% of cement with biochar made from woody materials, maintains the strength and affordability of conventional concrete while cutting emissions. The new funding will help her team assess whether sorted municipal waste can serve as a reliable biochar feedstock.
“If we’re able to solve some of the challenges with using municipal solid waste for biochar, the impact would be enormous," Tunstall said. “The combined emissions from concrete and municipal solid waste are staggering. Fourteen percent of global CO2 emissions is what we'd be addressing—that's equivalent to the entire aviation and passenger vehicle sectors combined.”
Through her startup, ZeroTwelve, and partnerships with ready-mix producers, Tunstall hopes to scale this technology to commercial use.