08/02/2016

Quantifying Global Energy Consumption for Water-Related Processes

Scientists find rising water-related energy consumption across the globe with pronounced differences among regions, sectors, and processes.

The Science

Rapid world population growth and rising living standards are driving increased demand for water and energy. At the same time, degradation of water resources and depletion of nonrenewable energy make meeting those demands increasingly challenging, even as climate change could aggravate regional water scarcity. A recent study, for the first time, quantifies water-related energy consumption over a 40-year period by water source, sector, and process for 14 global regions.

The Impact

This work directly points to the interplay between energy and the environment, enhancing understanding of the energy for water role in energy markets, and, more broadly, in the water-energy nexus. These findings could significantly influence both scientific undertakings in environment, hydrology, energy, climate change, and adaptation strategies, as well as region-specific environmental strategies.

Summary

Despite substantial efforts to quantify the interdependence of the water and energy sectors, global requirements of energy for water (E4W) are still poorly understood. The lack of quantitative information may provoke biases in projections and, consequently, in 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, E4W amounted to 10.2 exajoules of primary energy consumption 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, assuming median energy intensity levels. The researchers found the largest sectoral E4W allocation is municipal (45%), followed by industrial (30%), and agricultural (25%); the main process-level contributions are from source and conveyance (39%), water purification (27%), water distribution (12%) and wastewater treatment (18%). Additionally, the United States was the largest E4W consumer from the 1970s until the 2000s, but now 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.

Principal Investigator(s)

Leon Clarke
Pacific Northwest National Laboratory
Leon.Clarke@pnnl.gov

Mohamad Hejazi
Joint Global Change Research Institute
Mohamad.Hejazi@pnnl.gov

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.

References

Liu, Y., et al. 2016.“Global and Regional Evaluation of Energy for Water,” Environmental Science and Technology 50(17), 9736-45. DOI: 10.1021/acs.est.6b01065.

Kyle, P., et al. 2016. “Setting the System Boundaries of ‘Energy for Water’ for Integrated Modeling,” Environmental Science and Technology 50(17), 8930-31. DOI:10.1021/acs.est.6b01066.