Sustainable fleet operations through integrated optimization under techno-economic shipping and environmental constraints

The maritime sector faces increasing challenges as part of its ongoing transformation period towards more sustainable shipping: There is a shift in fuel preferences, with a gradual phasing out of high-polluting options in favor of cleaner, more sustainable alternatives, amidst increasingly stringent environmental policies pushing for greenhouse gases (GHG) emissions reduction, on top of the already complex techno-economic considerations for optimal shipping operations. These multifaceted challenges call for sophisticated, holistic solutions that can address economic, environmental, and operational aspects simultaneously. In response, the Global Climate Hub (GCH - an initiative under the UN Sustainable Development Solutions Network) develops integrated models to assess such problems and provide sustainable pathways. Here, we present such a model, the MaritimeGCH, a free, open-source, simple and comprehensive tool to address such challenges of maritime fleet management. MaritimeGCH integrates different techno-economic, environmental, operational factors and recent European environmental policies into a single, comprehensive model, which is at the same time simple and transferable to various scales. The optimization logic is first described for maritime problems; next the detailed mathematical description of MaritimeGCH model is presented; and finally, its potential for policy-relevant scenario analysis is outlined with specific examples. The model is publicly available to encourage similar applications and improvements.