Bias in Carbon Footprint Accounting of GIS: An Empirical Study Based on Ecoinvent and Chinese Local Data

Driven by the realistic demand for the optimization of carbon footprint accounting system for electric power equipment, this study conducted a comparative analysis of the whole life cycle based on the international ecoinvent database and the local Chinese database with GAS insulated SWITCHGEAR (GIS) as the research object. It revealed the systematic deviation of transnational databases in carbon accounting of electrical equipment via the system boundary definition and process level decomposition. The empirical data showed that, under the equivalent functional units, the calculation results of the Chinese local database increased by $6413.68 \mathrm{kgCO}_{2} \mathrm{eq}$ compared with the Swiss ecoinvent database, and the absolute deviation rate reached $19.97 \%$. Process analysis demonstrated the main causes of the accounting differences which include the following three aspects. First, regional differences in carbon emission factors in the energy production stage. Second, the lack of localization of processing efficiency parameters concerning upstream materials such as metal. Third, the timeliness deviation of process energy efficiency data is caused by the database update cycle. The results illustrated that the database selection determines the carbon footprint accounting of GIS. This study provides empirical evidence regarding deviations in transnational carbon accounting related to electrical equipment. It suggests that the construction of China’s local database can be improved in three dimensions: the dynamic update mechanism, industrial energy efficiency coupling, and regional correction. These results are conducive to the innovation of internationally recognized carbon accounting methodologies.