It is traditionally believed that energy security refers to the capability to prevent energy supply interruption. In recent years, environmental problems such as climate change have become increasingly serious. The traditional concept of energy security with the goal of supply security is gradually evolving into a new concept with the goal of low-carbon, cleanness and sustainability. The reason behind it is that the factors determining energy security are changing, which will deeply affect the world's energy system in the future. Energy technology is growing to be an important means to affect the world's energy pattern and achieve energy security.