A Thirst For Power: A Global Analysis Of Water Consumption For Energy Production

Via The Global Water Forum, a look at a recent report by The Center for Water-Energy Efficiency (CWEE):

Water and energy resource systems are fundamentally interrelated. Secure and reliable access to both resources is critical to basic survival, as well as ongoing economic development, at all scales and in every region of the world. At the most basic level, water is required in the production of energy, and energy is required in the treatment and transport of water – a linked relationship known as the water-energy nexus. While both sides of the water-energy nexus merit attention for improving resource use, this research effort focuses on the water requirements of energy systems and the associated implications for national water security.

As competition for finite freshwater resources intensifies around the world, it is increasingly important to balance the demand for water across multiple sectors while also protecting ecosystems.1 Understanding the water demand of energy systems is fundamental to overall national water security since the production of energy requires significant quantities of freshwater. While agricultural demand dominates overall demand for water in many regions of the world,2 the demand for water from the energy sector can be a major competitor. In the United States, it is a relatively even split between water withdrawals for irrigating crops (40% of total) and for cooling thermoelectric power plants (39%).3 Further, the division between agricultural and energy-based demand for water is no longer straightforward as irrigated crops are increasingly being converted to biofuels in many regions.4

Figure 1 (expand). Water consumption coefficients for energy technologies                                    (log scale)5,6,7,8,9,10,11,12

The quantity of water consumed by the energy sector varies substantially by the technology deployed for fuel extraction and processing (fossil fuels, nuclear fuels, and biofuels) as well as electricity production (thermoelectric and renewable technologies). As a regional portfolio of energy production technologies changes or expands, there is an associated fluctuation in the burden on local water resources. Figure 1 represents a consolidation from the literature of water consumption estimates for a variety of energy technologies (note that the estimates are provided in log scale to show variability within and across technology categories).

Given the potential impacts of energy policy decisions on regional water security, the application of metrics to assess the water burden of national energy portfolios is underdeveloped. Most of the literature has focused on estimating the water consumption of specific energy technologies (see sources listed for Figure 1); country-level or regional analyses of water consumption across a complete energy portfolio;13,14 or, a global analyses of water consumption by a single energy type.15 However, a clear estimation of water consumption for complete national energy portfolios at the global scale does not currently exist.

This research addressed this knowledge gap by synthesizing and expanding previous work to develop a global distribution of water consumption by national-level energy portfolios. The water consumption for energy production (WCEP) indicator was defined and calculated to quantify the relative water use of 158 national energy systems. WCEP is an estimation of freshwater consumption across all energy categories, including fossil fuels, nuclear fuels, biofuels, and electricity production. Hydroelectricity is not included in the analysis because its associated water consumption (often defined as the estimated evaporation from the reservoir) is only partially linked to energy consumption. The majority of dams serve multiple purposes, including the essential water security services of flood control and water storage.16 An overview of the global results of the WCEP assessment is provided in map form in Figure 2 below.

Figure 2 (expand). International results map for WCEP calculations

The results of the research estimate global WCEP at approximately 45 billion cubic meters of water per year. Of course, there is high variability in the WCEP across the 158 countries that were assessed (ranging from nearly zero to 12.6 billion cubic meters). As expected, the countries that are both larger in size and economic activity had the highest WCEP values. In terms of the per capita estimates for WCEP, the countries that were heavy producers of fossil fuel or biofuels demonstrated greater intensity of energy-based water consumption (see Figure 3). These results suggest that the economic imperative to develop fossil fuels drives higher WCEP, even in countries that lack sufficient water supplies. Meanwhile, biofuels require so much water that any national commitment to their production has significant water consumption implications.

Figure 3 (expand). Per capita water consumption for non-hydropower energy systems.

While these results are based on a comprehensive review of currently available data, future research in this area could be significantly enhanced through better data and widespread adoption of consistent reporting mechanisms. Additional opportunities to expand the field include increasing the resolution of the study regions, characterizing WCEP trends over time, and exploring innovative policy approaches to managing national WCEP effectively.

This research contributes an improved set of metrics to characterize the baseline conditions of integrated water-energy systems. By benchmarking water consumption for energy to standard measures, policy makers can better understand and track the status of this coupled system. They are then able to set targets to minimize water consumption or at least understand some of the water implications of particular energy policy initiatives. Given the critical role that the monitoring of greenhouse gas emissions has played in shaping energy portfolios, it is time to similarly incorporate water consumption implications into energy portfolio planning.

This entry was posted on Saturday, November 17th, 2012 at 12:09 am and is filed under Uncategorized.  You can follow any responses to this entry through the RSS 2.0 feed.  You can leave a response, or trackback from your own site. 

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About This Blog And Its Author
As the scarcity of water and energy continues to grow, the linkage between these two critical resources will become more defined and even more acute in the months ahead.  This blog is committed to analyzing and referencing articles, reports, and interviews that can help unlock the nascent, complex and expanding linkages between water and energy -- The Watergy Nexus -- and will endeavor to provide a central clearinghouse for insightful articles and comments for all to consider.

Educated at Yale University (Bachelor of Arts - History) and Harvard (Master in Public Policy - International Development), Monty Simus has held a lifelong interest in environmental and conservation issues, primarily as they relate to freshwater scarcity, renewable energy, and national park policy.  Working from a water-scarce base in Las Vegas with his wife and son, he is the founder of Water Politics, an organization dedicated to the identification and analysis of geopolitical water issues arising from the world’s growing and vast water deficits, and is also a co-founder of SmartMarkets, an eco-preneurial venture that applies web 2.0 technology and online social networking innovations to motivate energy & water conservation.  He previously worked for an independent power producer in Central Asia; co-authored an article appearing in the Summer 2010 issue of the Tulane Environmental Law Journal, titled: “The Water Ethic: The Inexorable Birth Of A Certain Alienable Right”; and authored an article appearing in the inaugural issue of Johns Hopkins University's Global Water Magazine in July 2010 titled: “H2Own: The Water Ethic and an Equitable Market for the Exchange of Individual Water Efficiency Credits.”