Experts attend the forum focusing on China's energy outlook to 2060 during the World Energy Congress in Turkey's Istanbul, on Oct. 10, 2016. China is leading the world in transition to a sustainable energy system, as the second largest economy is set to play a "decisive" role in helping transform the global energy sector in the decades to come, a Chinese expert on Monday told the 23rd World Energy Congress underway here. (Xinhua/He Canling)