Temporal validation of life cycle greenhouse gas emissions of energy systems in China

When assessing the environmental impact of a product or system, the life cycle assessment (LCA) is one of the most accepted methods. However, LCA relies heavily on the fundamental data sources, especially for energy related inventory database. The energy related inventory database is the basis of life cycle assessment for a product or system. Due to the great variety and the frequent updates of the energy related inventory database, the effect of temporal variables on life cycle inventory results should be quantified and interpreted in LCA case studies. In this study, a life cycle greenhouse gas (GHG) emissions calculation model for various energy sources is developed, and the life cycle GHG emissions of six types of energy in China in 2003 and 2013 are calculated and compared. There are significant reductions of 10.60-33.40% for different types of energy when using database of 2013 compared to 2003. To fill the temporal gaps, we develop a generic methodology for screening out the key temporal parameters in life cycle inventory analysis of energy upstream. Nine key temporal parameters related to the life cycle GHG emissions of six types of energy are screened out by sensitivity analysis coupled temporal variability analysis. The update interval of these parameters is quantified and suggested to ensure the reliability of analysis results. This methodology can help to reduce the maintenance workload of the database, and to provide a foundation for improving the reliability of life cycle analysis results for a product or system.