Abstract
Energy security was a major concern for OECD governments in the early 1970s. Since then, successive oil crises, volatility of hydrocarbon prices, as well as terrorist risks and natural disasters, have brought the issue back to the centre stage of policy agendas. Here, an energy security concept has been proposed, which is defined by time frame and space frame as well. Wide-meaning energy security is divided broadly into two categories. One is short-term (∼10 y) energy crisis, which is narrow-meaning energy security. Short-term energy crisis is further divided into contingent crisis, such as energy supply chain (sealane) interruption due to conflict, accident, terrorism, etc., and structural crisis, such as price fluctuations, supply shortage, energy demand increase in Asia, technology development stagnation, etc. The other is long-term (∼100 y) energy crisis and global energy problems, such as fossil fuel exhaustion and global warming.
