Implementing sustainable procurement through category management and ESG-based supplier evaluation: an EPC case study supported by the Operational Ethical Dilemma

Sustainable procurement has become a strategic organizational priority as companies increasingly seek to integrate environmental, social, and governance (ESG) principles into procurement decision-making while maintaining operational efficiency and long-term competitiveness. Despite the growing body of literature on sustainable procurement, limited research has examined its practical implementation within complex project-based industries. This study addresses this gap by presenting the implementation of a sustainable procurement framework within an international Engineering, Procurement, and Construction (EPC) contractor through the integration of Category Management, ESG-based supplier evaluation, and structured executive decision-making. The research adopts an implementation-oriented qualitative case study approach. A structured ESG assessment questionnaire, developed by the author and informed by internationally recognized sustainability principles, was applied annually to the organization’s twenty-five most strategically important suppliers based on procurement expenditure. Rather than conducting statistical analyses, the study focused on the individual evaluation of suppliers to support executive procurement decisions within a real organizational environment. The findings demonstrate that integrating ESG criteria into Category Management enables organizations to embed sustainability within existing procurement processes without fundamentally altering established procurement practices. The study further shows that while ESG assessments produce valuable operational evidence, final procurement decisions require executive judgement that balances operational findings with organizational strategy, stakeholder expectations, commercial priorities, and ethical responsibilities. To facilitate this process, the Operational Ethical Dilemma (OED) was applied as a managerial decision-support framework linking operational assessment with executive decision-making. The study contributes to both theory and practice by demonstrating a practical approach to implementing sustainable procurement in a complex EPC environment. It provides procurement professionals with an implementation framework that integrates Category Management, ESG-based supplier evaluation, and executive decision-making while supporting responsible procurement governance and long-term organizational sustainability.