The water footprint of the global power sector: Status quo, challenges, and opportunities for tackling the global water crisis

Abstract

Freshwater resources are becoming increasingly unavailable, and the competition for water resources among different sectors of the economy is worsening in many parts of the world. For instance, in the energy sector, the technologies currently used for electricity generation rely heavily on water availability. Examples of these technologies include hydropower plants that utilise the natural flow of moving water to generate electricity, thermal power plants (coal, gas, oil and nuclear) that require water for cooling purposes, and solar PV power plants in which water is deployed for cleaning of the PV modules. However, statistical data regarding water use in power plants is still scarce, since power plant operators do not usually disclose the amount of water needed during the power generation process.

This lack of statistical data impedes the assessment of water use in the global power sector and, consequently, limits the analysis of potential water use reduction. The aim of this research is to address this data gap by focusing on the global water demand of thermal power plants. By applying several energy system transition pathways, the water demand of the global power sector is estimated for the period 2015 to 2050 in five-year time intervals. The results of the study revealed that the global power sector currently consumes about 88 cubic kilometres of water annually, of which about 20 cubic kilometres of water evaporate due to the cooling of thermal power plants. It is demonstrated that the gradual decommissioning of a thermal power plant fleet during the energy system transition can annually ‘save’ about 98% of this cooling water, which will allow it to be allocated for other purposes—for instance, food production.

Subsequently, this analysis was expanded by applying energy transition pathways to 353 main global rivers. The results demonstrated that all water withdrawals from the main global rivers associated with thermal power generation can be fully mitigated by 2050. In addition, using the global cobalt supply chain as an example case, the study explored how the water demand of the power sector affects the water footprint of different products and services. The results revealed that the power system-related water demand represents about 90% of the total water footprint, allowing for a considerable water use reduction through the transition towards an energy system based on low water-demanding renewable energy technologies.

Present literature on water is focused on tackling rising water demand and reducing global water stress. To enhance this discussion, the water consumption criticality matrix was introduced, which draws attention to geographical areas that are potentially critical from the perspective of the availability of freshwater resources for current and future energyrelated water consumption.

Overall, this research sheds light on the use of water in the global energy sector and will contribute to the discussion of a sustainable energy transition from the perspective of energy-related water demand.