China has embarked on an ambitious and unprecedented programme of energy reform and climate change mitigation. Yet the motivations for this important shift remain unclear. This paper surveys key central government documents and articles by China’s leading energy academics to investigate the ideas influencing China’s new energy and climate policies. Three key ideas in particular are supportive of greater climate mitigation than in the past. First, domestic energy security concerns have risen on the central government agenda as a result of electricity shortages and rapidly rising energy consumption. Such concerns have deeply influenced China’s ambitious and largely successful energy efficiency policies. Second, growing awareness of the environmental constraints on economic growth in general, and the potential damages of dangerous climate change in particular, has prompted stronger official rhetoric in favour of green development. The appearance of targets and policies that specifically target carbon emissions reductions in the 12th FYP for the first time suggests that climate change mitigation is becoming a motivation for policy action in its own right, rather than simply a co-benefit of policies enacted for other purposes. Third, a conviction that the world is moving towards low-carbon energy forms has given rise to the belief that China must become a technological and economic leader in this transition. Large levels of public financing to support the development of China’s wind power and solar PV sectors suggests that the Chinese government has strong vested interests in seeing China successfully compete and lead in global low-carbon energy markets. In order to understand the shift in China’s approach to climate change since the 11th FYP, it is important to understand how new ideas such as these have reframed and reshaped the Chinese government’s interests and objectives.