On the Study of a Feasible LCA Method for the Ship Carbon Emissions Considering Uncertainty Correction

Mei, Menglei (Wuhan University of Technology) | Cai, Wei (Wuhan University of Technology) | Wang, Siqi (CNOOC Energy Technology & Services-oil Production Services Co.)

OnePetro 

ABSTRACT

In order to provide support to the green design of ships and relate marine structures, a practical and accurate evaluation model of life cycle carbon emissions is established. Based on the study of carbon emission characteristics at all stages of ship life cycle, this model adopts the life cycle assessment theory and introduces the uncertainty correction factors to accurately quantify carbon emissions. And the results can help guide the low-carbon design of ships. Finally, the feasibility and effectiveness of this model are verified by taking a 943 TEU river-sea-going container ship as an example.

INTRODUCTION

Carbon emissions give rise to several global environmental effects, like global warming and related sea level rise, ocean acidification, etc. In 2007, the total CO2 emissions in the shipping industry reached 1.046 billion tons. It represented 3.3% of the global emissions and the international shipping industry accounted for 2.7%. CO2 emissions from the shipping industry will grow by 150-250% in 2050 compared with 2007 if associated mitigation measures not be taken (Hui, 2016). Low-carbon design of ship has become one of the hot spots of green ship research. Sulaiman et al. (2013) demonstrated that the conceptual design stage of the ship has already determined 80% of the full life cycle environmental impact of the ship. Accurate evaluation of carbon emissions is the precondition to implement low-carbon design. Therefore, it is important to evaluate the carbon emissions of the ship life cycle in the preliminary design stage.

Life cycle assessment (LCA) is an important tool used to assess the environmental impact of the products and services in a “cradle to grave” perspective (BSI, 2006). Many researchers used the LCA theory to carry out researches on ship carbon emissions. Li (2010) analyzed the carbon emissions of a 180,000-ton bulk carrier by using the PAS2050 method, and pointed out that reducing the fuel consumption in the operation stage was an important way to reduce the ship carbon emissions. Based on the LCA theory, Chatzinikolaou et al. (2013) established a ship air emission analysis model to calculate the emissions of an oil tanker from four stages of ship life cycle (shipbuilding, operation, maintenance and dismantling). Fang (2015) expanded the study of ship carbon emissions into time and space dimensions, and analyzed the spatiotemporal distribution of ship carbon emissions in a life cycle perspective. Pommier et al. (2016) compared the environmental impacts of four kinds of hull materials (aluminum, composite, exotic wood and maritime pine) by using the LCA theory and ISO 14040 standards, and pointed out that wood had better environmental performance. The above studies generally analyzed the carbon emission characteristics of ship in the main life cycle stages, and demonstrated that the LCA theory can be employed for the ship carbon emission evaluation greatly. However, during the calculation of ship carbon emissions, the stochastic variation of the parameters at each stage of the life cycle will bring uncertainties to the calculation results, which will reduce the credibility of the results. Therefore, this paper takes the uncertainty into consideration and analyzes the influence of uncertain parameters on the ship carbon emissions so as to more accurately identify the carbon emission characteristics of ship in different life cycle stages.