Exploring the mechanisms of competition for water resources in the regional food and energy industries,taking effective countermeasures in advance will help to promote the sustainable development of the regional food and energy industries. Based on the theory of water footprint, this paper quantifies the water footprint of grain and energy in Shanxi Province, China, and the competition index of energy-grain industry to water resources. Through the ratio of grain blue water and energy water footprint to total water consumption in the region, this study coupled the characteristics of their proportional changes to obtain a competition index that can characterize the competition relationship between regional food and energy industries for water resources. The results showed that (1) In 2000–2021, although the grain yield increased by 81.1%, the grain water footprint only increased by 11.2%, with an average annual growth of 1.0%. The proportion of blue, green and gray water footprints changed from 14.1%, 54.3% and 31.6% in 2000 to 18.8%, 41.2% and 39.9% in 2021, respectively. (2) The energy water footprint increased at an average annual rate of 10.8%, an increase of 544.7% over the period. The coal, natural gas and thermal water footprints in 2021 have increased by a factor of 2.7, 109.2 and 4.0, respectively, compared to 2000. Coal’s share of the energy water footprint is 70.6%. (3) The average value of the food and energy industry’s competition index for water resources is 0.77, increasing from 0.42 in 2000 to 0.94 in 2021, an average annual increase of 4.3%. These results show that the future sustainable development of the region is facing the major challenge. Therefore, from the perspective of reducing the demand for crop and energy water footprint, some suggestions are put forward to effectively promote the healthy development of the region.
