Assessing the impacts of economy-wide emissions policies in the water, energy, and land systems considering water scarcity scenarios

Nowadays, global water shortages are an important challenge, due to the implications of water use in the agricultural, industrial, and energy sectors. In fact, one of the largest consumers of water is the energy sector, due to intensive water demand for cooling processes of fossil fuel power plants, or for the extraction of shale gas resources. Although there has been a 22% reduction in the use of water in the power sector from 2015 to 2020 (due to the increase of renewable energy), there is still a significant yearly volume of 47.5 trillion gallons needed for cooling of fuel based power plants in the United States. Therefore, water shortage generates integrated planning challenges among energy, water, and land systems when planning economy-wide transitions towards carbon neutrality. This paper evaluates carbon budgets consistent with those declared by the US Nationally Determined Contributions under water scarcity conditions in the context of energy–water–food nexus. The Global Change Analysis Model at the US state level (GCAM-USA) is used for this purpose. This model integrates different systems that allow us to study different mitigation strategies for these budgets for the US energy system. The results indicate that in order to achieve the US NDC, electrification of final demand sectors is required, reaching increased electricity supply of up to 90%. The mix of wind, solar, and CCS (gas and biomass) technologies that will supply that increased electricity demand depend on the level of water availability. Indeed, when water constraints are imposed, it is observed the that land sector is not able to supply biomass to the power sector, resulting in a 12% reduction of biomass based electricity participation.