Using carbon dioxide as a chemical feedstock instead of oil would reduce annual global greenhouse gas emissions by about 3.5 billion metric tons (t) in 2030. This estimate, based on a new model of the chemical industry, is about an order of magnitude greater reduction than previous ones (Proc. Natl. Acad. Sci. U.S.A. 2019, DOI: 10.1073/pnas.1821029116).
Without an in-depth life-cycle analysis of CO2 use by the chemical industry, scientists have previously estimated it would mitigate about 200 million t of CO2 per year. Sangwon Suh, an environmental scientist at the University of California, Santa Barbara, collaborated with André Bardow, an expert in chemical life-cycle analysis at RWTH Aachen University, to fill in the details. Their work is based on a quantitative data set that includes details about the processes involved in emerging technologies for using captured CO2 and renewable energy to make chemicals such as methane, olefins, and styrene. They compared this information to data about conventional chemical processes and found that carbon capture and utilization by the chemical industry could play a significant role in mitigating climate change.
However, it’s still not practical on a large scale. A carbon-neutral chemical industry will require “a ginormous amount of energy,” Suh says—about 18.1 petawatt-hours in 2030, more renewable energy than the world is on track to produce by that time. “At some point, we have to face the problem of how to make a carbon-neutral chemical industry,” Bardow says. In the meantime, the researchers conclude that we’re better off using renewable electricity to electrify transportation and heating.