The quantification of drivers of CO2 emissions from the electricity generation sector is an area that has attracted a great deal of attention among researchers and policy makers. Index decomposition analysis is a technique that has been widely used for this purpose. The increasing interest, however, has led to the usage of a variety of formulae in the decomposition. In this paper, a literature survey on the related publications is first compiled. Based on the survey, key features of studies and development trends are discussed. The decomposition formulae used are systematically analysed to elucidate the differences and relationships among them. An approach which quantifies the share of fossil fuels in the electricity mix and considers the generation efficiency by fuel type is recommended as it leads to the most comprehensive and meaningful decomposition results. Further extensions to the current practice to include factors such as transmission and distribution losses as well as carbon capture and storage are also discussed. The findings and recommendations provide insights into the analysis of CO2 emissions from the electricity generation sector where major structural changes are expected to take place in future.