Author: Mark Z. Jacobson Dept. of Civil & Environmental Engineering, Stanford University, Stanford, CA, USA. Email: jacobson@stanford.edu
Abstract: Spending money on carbon capture and storage or use (CCS/U) and synthetic direct air capture and storage and use (SDACCS/U) increases carbon dioxide equivalent (CO2e) emissions, air pollution, and costs relative to spending the same money on clean, renewable electricity replacing fossil or biofuel combustion. In a recently published paper in Energy and Environmental Sciences on this issue (doi:10.1039/c9ee02709b), I analyzed data from an existing coal-CCU plant and an SDACCU plant. A net of only 10.8% of the CCU plant’s CO2e emissions and 10.5% of the CO2 removed from the air by the SDACCU plant are captured over 20 years, and only 20-31%, are captured over 100 years. The low net capture rates are due to uncaptured combustion emissions from natural gas used to power the equipment, uncaptured upstream emissions, and, in the case of CCU, uncaptured coal combustion emissions. Moreover, the CCU and SDACCU plants both increase air pollution and total social costs relative to no capture. Using wind to power the equipment reduces CO2e relative to using natural gas but still allows air pollution emissions to continue and increases the total social cost relative to no carbon capture. Conversely, using wind to displace coal without capturing carbon reduces CO2e, air pollution, and total social cost substantially. Further, using wind to displace coal reduces more CO2e than using the same wind to power the capture equipment. As such, spending money on wind powering carbon capture always increases CO2e compared with spending on the same wind replacing fossil fuels or biofuels. In sum, CCU and SDACCU increase or hold constant air pollution health damage and reduce little carbon before even considering sequestration or use leakages of carbon back to the air. Spending on capture rather than wind replacing either fossil fuels or bioenergy always increases CO2e, air pollution, and total social cost substantially. No improvement in CCU or SDACCU equipment can change this conclusion while fossil power plant emissions exist, since carbon capture always incurs an equipment cost never incurred by wind, and carbon capture never reduces, instead mostly increases, air pollution and fuel mining, which wind eliminates. Once fossil power plant emissions end, CCU (for industry) and SDACCU social costs need to be evaluated against the social costs of natural reforestation and reducing nonenergy halogen, nitrous oxide, methane, and biomass burning emissions.
Read Jacobson’s complete paper in Energy & Environmental Science.