This is an intriguing topic. The data are listed in the following Table 1 cited from the CIA world factbook (website).
Table 1:
| Annual energy consumption (kwh) per capita (data source: CIA World Factbook website - access on Sept 22, 2017) | |||
| Europe Union | USA | China | |
| Popultation | 516,195,432 | 326,625,791 | 1,379,302,771 |
| Annual energy consumption | 2,771,000,000,000 | 3,913,000,000,000 | 5,920,000,000,000 |
| Annual energy consumption per capita | 5368 | 11980 | 4292 |
| GDP (US dollars)_ppp | $19,180,000,000,000 | $18,560,000,000,000 | $21,270,000,000,000 |
| GDP per capita (US dollars)_ppp | $37,156 | $56,823 | $15,421 |
| Physical GDP (US dollars) | $5,063,520,000,000 | $3,804,800,000,000 | $10,486,110,000,000 |
| Physical GDP (US dollars) per capita | $9,809 | $11,649 | $7,602 |
| Annual energy consumption per capita | 5368 | 11980 | 4292 |
| GDP(US dollars)_nominal | 16,270,000,000,000 | $18,560,000,000,000 | $11,390,000,000,000 |
| GDP(US dollars)_nominal per capita | $31,519 | $56,823 | $8,258 |
| Annual energy consumption per capita (AECPC) | 5368 | 11980 | 4292 |
| Comparison to China in AECPC | 1.3 | 2.8 | 1.0 |
The data indicate that USA per capita annual energy consumption (aecpc) is 11980 kwh, the EU aecpc is 5368 kwh, and China is 4292 kwh. In other words, each American people consumes 2.8 times more energy than a people in China each year; a people in EU uses 1.3 times more energy than a people in China a year. However, a American produces $56823 GDP (in terms of exchange rate), seven times higher than a people in China. A people in EU produces $31519 GDP, three times more than a person in China. Such a comparison raises a big question - how can per capita 2.8 times more energy consumption generating 7 times more GDP when USA is compared with China, and 1.3 times more energy usage creating 3 times more GDP when comparing the EU and China on the basis of per capita?
The conclusion is obvious - there must be a problem in estimate of a nation's GDP given the physical law is correct!
It is really surprising to see that China has made a great progress in growing her economy and in improving people's living standard. In fact, common people in China enjoy pretty good life even though more development is still needed in some of the aspects in the near future.
The above data suggest that if a national currency is backed by production (vs consumption), then a US dollar must be equal to 2.8 China Yuan and one Euro should equal 1.3 China Yuan. This implies the China currency is much undervalued when exchanging with the US dollar or Euro. If this is right, then China GDP must be 75 trillion China Yuan (2016)/2.8 US dollar equal to ~$27 trillion US! Thus, China per capita GDP 2016 must be ~US$20000, that might epxlain the average living conditions of people in China!