A life cycle assessment study of a Canadian post-combustion carbon dioxide capture process system

Purpose

While carbon dioxide capture and storage (CCS) has been widely recognized as a useful technology for mitigating greenhouse gas emissions, it is necessary to evaluate the environmental performance of CCS from a full life cycle perspective to comprehensively understand its environmental impacts. The primary research objective is to conduct a study on life cycle assessment of the post-combustion carbon dioxide capture process based on data from SaskPower’s electricity generation station at the Boundary Dam in Saskatchewan, Canada. A secondary objective of this study is to identify the life cycle impact assessment (LCIA) methodology which is most suitable for the assessment of carbon dioxide capture technology integrated with the power generation system in the Canadian context.

Methods

The study takes a comparative approach by including three scenarios of carbon dioxide capture at the electricity generation station: no carbon dioxide capture (“no capture”), partial capture (“retrofit”), and fully integrated carbon dioxide capture of the entire facility (“capture”). The four LCIA methods of EDIP 97, CML2001, IMPACT2002+, and TRACI are used to convert existing inventory data into environmental impacts. The LCIA results from the four methods are compared and interpreted based on midpoint categories.

Results and discussion

The LCA results showed an increase in the retrofit and capture scenarios compared to the no capture scenario in the impact categories of eutrophication air, ecotoxicity water, ecotoxicity ground surface soil, eutrophication water, human health cancer ground surface soil, human health cancer water, human health noncancer ground surface soil, ozone depletion air, human health noncancer water, and ionizing radiation. The reductions were observed in the retrofit and capture scenarios in the impact categories of acidification, human health criteria air-point source, human health noncancer air, ecotoxicity air, global warming, human health cancer air, and respiratory effects.

Conclusions

Although the four LCIA methodologies significantly differ in terms of reference substances used for individual impact categories, all (TRACI, IMPACT2002+, CML2001, and EDIP 97) showed similar results in all impact categories.