ABSTRACT
Power lithium-ion batteries (LIBs) are an important component of carbon neutrality in the transportation sector. The rapid growth of the LIB recycling industry is driven by various factors, such as resource scarcity. As a process interacting upstream and downstream, LIB recycling must consider the impact of the application of modeling approaches on the allocation of environmental benefits and burdens, especially at a time when carbon emissions are highly correlated with profit. In this study, seven allocation methods were chosen and applied to the production and multiple recycling process of typical LIB on the same data basis. The application of different allocation methods produced very disparate allocation results, and the conclusions of previous studies comparing the environmental performance of battery types need to be revisited. The life-cycle assessment (LCA) results should be interpreted with caution due to the impact of the allocation methods. Furthermore, a multi-indicator qualitative analysis based on product and process characteristics compares the applicability of the allocation methods to different aspects of LIB recycling. Relevant product standards for batteries should consider the characteristics of different methods and recommend a specific allocation method for the LCA community to employ in time to ensure that relevant studies are representative and comparable.
ABSTRACT
As the largest magnesium producer in the world, China is facing a great challenge of greenhouse gas (GHG) emissions reduction. In this paper, the variation trend and driving factors of GHG emissions from Chinese magnesium production were evaluated and the measures of technology and policy for effectively mitigating GHG emissions were provided. First, the energy-related and process-oriented GHG inventory is compiled for magnesium production in China. Then, the driving forces for the changes of the energy-related emission were analyzed by the method of Logarithmic Mean Divisia Index (LMDI) decomposition. Results demonstrated that Chinese magnesium output from 2003 to 2013 increased by 125%, whereas GHG emissions only increased by 16%. The emissions caused by the fuels consumption decline most significantly (from 28.4 to 6.6 t CO2eq/t Mg) among all the emission sources. The energy intensity and the energy structure were the main offsetting factors for the increase of GHG emissions, while the scale of production and the international market demand were the main contributors for the total increase. Considering the improvement of technology application and more stringent policy measures, the annual GHG emissions from Chinese primary magnesium production will be controlled within 22 million tons by 2020.
