Executive Summary The past decade has seen the development of various scenarios describing long-term patterns of future Greenhouse Gas (GHG) emissions, with each new approach adding insights to our understanding of the changing dynamics of energy consumption and aggregate future energy trends. With the recent growing focus on China's energy use and emission mitigation potential, a range of Chinese outlook models have been developed across different institutions including in China's Energy

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... al Laboratory (LBNL) has developed a bottom-up, end-use energy model for China with scenario analysis of energy and emission pathways out to 2050. A robust and credible energy and emission model will play a key role in informing policymakers by assessing efficiency policy impacts and understanding the dynamics of future energy consumption and energy saving and emission reduction potential. This is especially true for developing countries such as China, where uncertainties are greater while the economy continues to undergo rapid growth and industrialization. A slightly different assumption or storyline could result in significant discrepancies among different model results. Therefore, it is necessary to understand the key models in terms of their scope, methodologies, key driver assumptions and the associated findings. A comparative analysis of LBNL's energy end-use model scenarios with the five above studies was thus conducted to examine similarities and divergences in methodologies, scenario storylines, macroeconomic drivers and assumptions as well as aggregate energy and emission scenario results. Besides directly tracing different energy and CO 2 savings potential back to the underlying strategies and combination of efficiency and abatement policy instruments represented by each scenario, this analysis also had other important but often overlooked findings. The key findings drew from the comparative studies could be summarized as follows: Methodology and Scenarios Although the modeling studies reviewed all present detailed energy and carbon outlooks for China to 2030 or later, they differ in their modeling methodology and scenarios analyzed. ERI and Tyndall are the only two studies that incorporated a top-down modeling approach while LBNL, McKinsey and IEA all employed bottom-up modeling and analysis approach with physical drivers to different extents. LBNL's model based its assumptions mostly on physical drivers for energy activities for the end use and technologies instead of economic drivers such as price, and GDP growth rate. The IEA model had sectoral breakdown, but not at a disaggregated end-use level as those in LBNL, ERI and McKinsey's studies.