The concern of the EFCE for sustainability. Four recent case studies to illustrate how CAPE tools contribute to process sustainability: (1) ultimate plant operation at Wacker-Chemie(DE), (2) development of a new sulphuric acid plant with Air Liquide (FR), (3) plant retrofit for CO2 abatement at Kemira (BE), (4) insertion of a new plant in an existing Solvay industrial site (Asia)