This study investigates the energy implications of various pathways of China's power decarbonization in terms of RES power penetration and coal consumption. It complements our previous work in [1] which stressed the economic effectiveness and CO2 emission reductions. Based on the results of these two works, here we analyze the trade-offs of the energy-environmental-economic (3E) objectives of the pathways. We find that although CCS technology can help achieve a cost effective and a high degree of CO2 emission abatement, it results in an additional coal consumption and cost disadvantages of RES power. Accordingly, if China heavily relies on CCS technology to achieve power decarbonization, the long-term energy sustainability is undermined. The challenges for policy makers are therefore to design comprehensive packages which are mutually reinforcing or at least compatible with acceptable costs in achieving the 3E objectives for the power decarbonization. With an empirical review of the past policy designs, we also find that China favors energy sustainability, yet neglecting the economic effectiveness and CO2 emissions. The institutional environment including the government's attitudes towards climate change, the development of ETS market and the reforms on electricity price, will largely influence the deployment of low-carbon technologies and thus the pathways of power decarbonization.