In ship design, since the early stage, there is an increasing need to compare different design solutions analysing ship performances along the whole life-cycle frame, not only from the economical point of view, but also in terms of the environmental aspects.

To this aim, an approach is proposed to carry out the assessment of both cost and environmental performances on a comparative basis, among different ship design solutions.

A blended formulation between Life Cycle Cost (LCC) and Life Cycle Assessment (LCA) is developed, with the option nevertheless to keep also each selected Key Performance Indicator (KPI) as a separated source of information.

Significant KPIs are specifically identified and discussed; then a formulation is proposed for a comprehensive evaluation by means of a single index of Life Cycle Performance Assessment (LCPA). The harmonized formulation allows a rationally based comparison between projects and solutions, giving a weight to each selected KPI according to priorities of designers and ship owners/operators. A Ship Breakdown Structure has been developed to link ship design parameters with calculation of KPIs.

Though the end of life is an essential phase to be accounted for in a life cycle evaluation, the practical approach presented in this paper is limited to Design/Construction and Operations. Decommissioning issues have been postponed to a future activity, keeping in mind that the topic is very much related to owners company policy and strongly dependant on details not available yet in the conceptual ship design phase.

The decision-making activity during the ship design process needs to be supported by quantitative evaluations, properly projected over the whole ship lifetime range. In the paper, the structure of a bottom up procedure is proposed, starting from low level information and data (e.g. ship characteristics and operational profile) and arriving to a single parameter (LCPA index), by means of selected KPIs and their linear combination. Indeed, one of the great challenges is the availability and selection of appropriate data, needed to quantify KPIs during the design stage.

The approach has been implemented and applied to a Ro-Ro passenger ship in order to verify and validate the LCPA tool structure and its reliability.