Container vessels—characterized by high transport work and energy-demanding operating profiles—constitute one of the most emission-significant fleet segments and a strategically important area for implementing and assessing decarbonization initiatives. Responding to the persistent absence of integrated analytical approaches, this paper introduces a unified techno-economic and environmental assessment framework for evaluating green interventions on operating ships. The framework comprises a set of fuel-consumption, environmental performance, and techno-economic metrics and a transparent and globally applicable assessment procedure enabling the consistent comparison of heterogeneous intervention types towards sustainability. The framework is applied to a representative medium-size container vessel to demonstrate its analytical potential and practical relevance. The results of the specific application reveal the systematic trade-offs between environmental and economic performance of green interventions: operational optimization delivers the strongest carbon-intensity improvements and isolated technical retrofits provide favorable economic returns but limited environmental gains, while integrated technical–operational packages achieve the most balanced overall outcomes. Overall, the paper has both a methodological contribution by suggesting a coherent, regulation-aligned assessment structure, as well as a practical decision-support value for ship operators and policymakers.
Mouzakitis et al. (Sat,) studied this question.