As companies try to embrace life cycle thinking, Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) have proven to be powerful tools. In this paper, an Environmental Input-Output model is used for analysis as it enables an LCA using the same economic input data as LCC. This approach helps align LCA and LCC while avoiding cut-offs in the LCA. The efficacy of the method is illustrated by a real case study of a tanker ship.
The study examines five sister medium-range tankers carrying clean petroleum products, including naphtha, gas oil, jet fuel and biofuels. The functional unit is one average year of ship transport, expressed through the cargo moved and distance travelled. The authors translate life cycle cost cash flows into environmental impacts using a hybrid environmental input-output model. More than 300 cash flows are assigned to representative economic sectors, while available physical data for fuel, energy and materials are used directly. This combines detailed operational information with estimates of impacts across the wider supply chain.
For the modelled vessel, the study reports 11.1 g CO₂-equivalent per tonne-kilometre. Fuel is the main contributor: combustion accounts for 79.1% of greenhouse-gas emissions, while fuel production and other fuel-related emissions bring its climate-change contribution to 88.9%. The analysis presents climate-change results only. It does not assess other maritime issues such as ballast-water impacts, antifouling biocides, oil spills, waste and sewage, or hazardous materials released during ship scrapping. The authors also treat the first five operating years as representative of later service cycles, an assumption to consider when interpreting the case results.
