LCA of CCS and CCU compared with no capture: How should multi-functional systems be analysed?

Abstract

CCS (carbon capture and storage) is a means of reducing greenhouse gas emissions by capturing and subsequently storing the CO2, while CCU (carbon capture and utilisation) is a way of recycling the carbon in the captured CO2 by converting it into new products. CCS aims at improving the results for one environmental indicator while CCU represents a multi-functional system. It is therefore crucial, when comparing CCU with CCS or no capture, that more than one indicator is used. Also vital is the need to establish relevant system boundaries and to define a joint functional unit, so as to create a robust decision basis for the selection of the environmentally preferable option.