Estimating Global Energy Use for Water-Related Processes

The Science

Newswise — Rapid world population growth and rising living standards are increasing the demand for both water and energy. Water resources are degrading. Nonrenewable energy sources are being depleted. These changes to water and energy make meeting rising demands more challenging. Add to that, climate change could aggravate regional water scarcity. The challenge was better understanding changes in energy use for water-related processes. A team estimated global historical water-related energy use over a 40-year period across 14 global regions.

The Impact

This work directly enhances our understanding of how energy and water systems are inter-connected. It provides these insights by examining the role of energy-for-water in energy markets. The findings could influence regional strategies. In addition, the results could affect scientific efforts in hydrology, energy, climate change, and adaptation.

Summary

Despite substantial efforts to quantify the interdependence of the water and energy sectors, global requirements of energy for water transport, treatment, and distribution are still poorly understood. The lack of quantitative information may lead to biases in projections and, consequently, water and energy management strategies. In a recent study, researchers from Pacific Northwest National Laboratory estimated global and regional primary energy consumption for water. They estimated water-related energy consumption by water source, sector, and process for 14 global regions from 1973 to 2012. Globally, energy for water consumed 10.2 exajoules of primary energy in 2010, accounting for 1.7% to 2.7% of total global primary energy consumption, of which 58% pertains to surface water, 30% to groundwater, and 12% to non-fresh water. The researchers found the largest sectoral allocation of energy for water use is municipal (45%), followed by industrial (30%), and agricultural (25%). The main process-level contributions are from source and conveyance (39%), purification (27%), distribution (12%), and wastewater treatment (18%). The United States was the largest energy for water consumer from the 1970s until the 2000s. Now, however, the largest consumers are the Middle East, India, and China, driven by rapid growth in desalination, groundwater-based pumping for irrigation, and industrial and municipal water use, respectively. These findings will enable enhanced consistency of both water and energy representations in integrated assessment models.

Funding

This research was supported by the U.S. Department of Energy, Office of Science, Office of Biological and Environmental Research through the Integrated Assessment Research program.

Publications

Y. Liu, M. Hejazi, P. Kyle, S.H. Kim, E. Davies, D.G. Miralles, A.J. Teuling, Y. He, and D. Niyogi, “Global and regional evaluation of energy for water.” Environmental Science and Technology 50(17), 9736-9745 (2016). [DOI: 10.1021/acs.est.6b01065]

P. Kyle, N. Johnson, E. Davies, D.L. Bijl, I. Mouratiadou, M. Bevione, L. Drouet, S. Fujimori, Y. Liu, and M. Hejazi, “Setting the system boundaries of ‘energy for water’ for integrated modeling.” Environmental Science and Technology 50(17), 8930-8931 (2016). [DOI: 10.1021/acs.est.6b01066]