Domestic oil and gas or imported oil and gas - an energy return on investment perspective

Both domestic oil and gas and imported oil and gas are essential to meet the enormous energy demand in China, which is incurred by its rapid economic growth. However, which is better than another? To address this issue, an energy return on investment (EROI) analysis, which is a useful method to evaluate the physical performance of an energy process, is applied. Besides, the EROIs time series of offshore domestic oil and gas and onshore domestic oil and gas are calculated, and the causes of the change tendency of EROIs time series are studied. The EROIs of imported oil and gas from different import countries are also calculated, laying the foundation for optimization of the import structure from an EROI perspective. Moreover, environmental inputs, which cause the externality of an energy process, are also studied. The results show that the EROIs of the entire domestic oil and gas fluctuate between 8.5 and 12, and the EROIs of the imported oil and gas lie in the range between 2.9 and 9.5. We conclude that: 1) The EROIs of domestic oil and gas is higher than those of imported oil and gas, indicating that domestic oil and gas has a higher physical efficiency than imported oil and gas. 2) The change tendency of EROIs is influenced by the extractions of natural gas. Moreover, the EROIs of imported oil and gas are additionally related to oil and gas prices. 3) From an EROI perspective, LNG and pipeline gas are better than imported crude oil. Australia, Kazakhstan, and the USA should be prioritized for China to import LNG, pipeline gas, and crude oil respectively. 4) Environmental inputs reduce the EROIs. Therefore more caution should be paid on the reduction of environmental inputs