## 3 Differences in Energy Intensity and Sector Structure among the G20 Countries  
The total energy consumption of the G20 countries increased from 2000 to 2014. Figure 1 shows that China and the United States consume significantly more energy than other G20 countries. In 2014, the average energy consumption of the G20 countries was 73 EJ. The energy consumption of China, the United States, Russia, and India is higher than the average value of all G20 countries at 342 EJ, 275 EJ, 100 EJ, and 90 EJ, respectively. Thus, reducing the total energy consumption of these four countries has great potential to reduce global energy consumption and improve energy efficiency. The gap in aggregate energy intensity among the G20 countries tended to converge from 2000 to 2014. Reducing energy intensity in Russia, India, China, and South Korea has great potential to reduce global energy consumption and improve energy efficiency. Each point in Figure 2 represents the ratio of the energy intensity of each G20 country in 2000-2014 to the average energy intensity of the G20 countries in the corresponding year. The average energy intensity of the G20 countries in 2000, 2005, 2010, and 2014 is 15.98 EJ per million dollars, 13.27 EJ per million dollars, 10.85 EJ per million dollars, and 9.81 EJ per million dollars, respectively. The average energy efficiency of the G20 countries increased yearly from 2000 to 2014. At the same time, the gap between the energy intensity of each G20 country and the average energy intensity of the G20 countries tended to converge from 2000 to 2014. The largest convergence was observed for the gap between the energy intensity of Russia and the average level. Despite a converging trend, the energy intensity of Russia, India, China, South Korea, Indonesia, and Canada in 2014 was still higher than the average level of the G20 countries. In 2014, the highest energy intensity was Russia's, which registered a value 2.94 times the average level of the G20 countries, followed by those of India (2.07 times), China (1.62 times), and South Korea (1.54 times). It should be noted that developed countries such as the United States and those in European countries have higher energy efficiencies, while post-industrial countries such as Russia, China, India, and South Korea have lower energy efficiencies. According to Figures 1 and 2, the optimization of energy efficiency in Russia, India, China, and South Korea has great potential for global energy consumption reduction and energy efficiency  
Figure 1: Energy consumption of Group of Twenty (G20) countries from 2000 to 2014. Figure 2: Ratio of G20 countries and groups average energy intensity. improvement. As can be seen from Figure 1, the energy consumption of the United States is much higher than that of other developed countries, but its energy intensity in Figure 2 is much lower than the average level of the G20 countries. This indicates that the United States, being the world leader in technology, has a much higher energy efficiency than other G20 countries. However, although it consumes a large amount of energy every year, it has shifted some production activities characterized by high energy consumption, high pollution, and low economic efficiency to other export-oriented countries, thus reducing its energy intensity. Each point in Figure 3 represents the ratio of the EEI of key sectors to the average level of corresponding sectors. In 2014, for example, most of the key industries in Russia, China, India, and South Korea had a higher energy consumption intensity than the average levels of their corresponding industries.