March 30, 2021

Assessing the Future of Global Energy-for-Water

Quantifying the energy requirements of future agricultural, industrial, and municipal water sector use

Water treatment plant with large outdoor tanks of frothy water

Studies calculating energy use from the water sector must account for present and future levels of energy-intensive wastewater treatment.

(Image by the Montgomery County Planning Commission |

The Science

Energy statistics and models typically group water-related energy use (i.e., “energy-for-water” or EFW) with all other energy uses in the commercial, industrial, and/or agricultural sectors. While historical EFW has been studied extensively, no global-scale future projections of this key component of the water-energy nexus are available. This study re-constructs regional and global energy balances to explicitly disaggregate EFW by process (water abstraction, treatment, desalination, distribution, and post-use wastewater treatment) and incorporates EFW into the Global Change Analysis Model. It then projects future EFW under a range of scenarios that meet selected Sustainable Development Goals to examine the primary energy footprint of water system changes.

The Impact

This is the first study to quantify the scale of future EFW; it demonstrates appropriate system boundaries for representing EFW in multi-sector models and provides both detailed methods and data to facilitate such an endeavor for other modeling teams. The study shows the future growth of this energy demand in a variety of scenarios and provides estimates of the full-system energy footprint of achieving water-related Sustainable Development Goals. The study also highlights the future increase in the energy intensity of water production in all regions, finding significant increases in several regions (the Middle East, Pakistan, and India) that, over time, rely increasingly on deep groundwater pumping and seawater desalination.


Energy-for-water is a key component of the water-energy nexus that will increase in scale with future water scarcity, water use, and associated treatment requirements. This study incorporates EFW into the Global Change Analysis Model to produce long-term global projections of EFW in a variety of scenarios, constructed to represent the achievement of several water-related Sustainable Development Goals. In the scenarios, global EFW increases by a factor of 2.5 from 2015 to 2050 in the baseline scenario and by a factor of 4 in a scenario with expanded irrigation, municipal water access in all regions, and significant reductions in the untreated wastewater discharged across all regions. Importantly, the energy intensity of water production (the sum of abstraction and desalination) increases by a factor of 3 globally from 2015 to 2050, due to future water-scarcity-driven increases in the use of seawater desalination and deep groundwater pumping.

PNNL Contact

Katherine Calvin, Pacific Northwest National Laboratory,


This research was supported by the U.S. Department of Energy, Office of Science, as part of research in MultiSector Dynamics, Earth and Environmental System Modeling program.

Published: March 30, 2021

P. Kyle, M. Hejazi, S. Kim, P. Patel, N. Graham, and Y. Liu. “Assessing the Future of Global Energy for Water,” Environmental Research Letters, 16, 024031, (2021).