The paper offers an analysis of how an energy-monitoring system was implemented and eventually adopted by the crew members in a shipping company. It illustrates how the social process of enacting the system as a collaborative technology-in-practice, enabling a significant reduction in energy consumption, was contingent on the negotiation of meaning and mutual learning among crew members in their community of practice. The case study contributes to the literature on the relation between information technology, organization and energy efficiency by investigating the socially situated nature of technology implementation and work practice change. The findings’ implications for the role of information technology in improving energy efficiency in shipping are discussed.