A new Pacific Institute report is out – Water for Energy: Future Water Needs for Electricity in the Intermountain West – which examines the water requirements for current and projected electricity generation within the Intermountain West. As the report notes, under current trends, by 2035, water withdrawals and consumption for electricity generation in the region are projected to increase by 2% and 5%, respectively, over 2010 levels – but water availability is already affecting power plant operations and siting in the Intermountain West. And in addition to the water needed for electricity generation, population and economic growth will increase demands for water resources, even as climate change makes the available water supply less reliable. An extract of its summary and conclusions is as follows:
“..In the past few years, there has been a growing interest in the complex connections between energy and water, typically called the energy-water nexus. For much of the 20th century, these two vital resources have largely been analyzed and managed separately, with different tools, institutions, definitions, and objectives. We now know, however, that there are very important links between water and energy and that long-term sustainable use of both resources requires more comprehensive and integrated study and management. The current report addresses the water implications of energy choices and offers some new insights into the water risks of different electricity futures.
The energy sector has a major impact on the availability and quality of the nation’s water resources (Table 1). Water is used to extract and produce energy; process and refine fuels; construct, operate, and maintain energy generation facilities; cool power plants; generate hydroelectricity; and dispose of energy-sector wastes. Some of this water is consumed during operation or contaminated until it is unfit for further use; often much of it is withdrawn, used once, and returned to a watershed for use by other sectors of society.
Energy use also affects water quality and ultimately human and environment health. The discharge of waste heat from cooling systems, for example, raises the temperature of rivers and lakes, which affects aquatic ecosystems. Wastewaters from fossil-fuel or uranium mining operations, hydraulic fracturing, boilers, and cooling systems may be contaminated with heavy metals, radioactive materials, acids, organic materials, suspended solids, or other chemicals (EPA 2011, Urbina 2011). Nuclear fuel production plants, uranium mill tailings ponds, and under unusual circumstances, nuclear power plants, have caused radioactive contamination of ground- and surface-water supplies (EPA 2010). Too often, however, these water-quality impacts are ignored or inadequately understood.
Conflicts between energy production and water availability are on the rise as the overall pressure on scarce water resources intensifies. Rising energy costs and concerns about greenhouse gas emissions are forcing some water managers to seek ways optimize the energy efficiency of their water systems. Likewise, water scarcity is beginning to affect energy production, even in areas not traditionally associated with water-supply constraints. Water-energy conflicts are most acute during a drought, especially in the summer, when energy demands are high and water availability is particularly low. For example:
- In September 2010, water levels in Lake Mead dropped to 1,084 feet, levels not seen since 1956, prompting the Bureau of Reclamation to reduce Hoover Dam’s generating capacity by 23%. As water levels continued to drop and concerns about climate change intensified, dam operators were concerned that reductions in the electricity generating capacity would destabilize energy markets in the southwestern United States (Walton 2010).
- In August 2007, river flows and reservoir levels in the southeastern United States dropped due to drought, and in some cases, water levels were so low that power production was halted or curtailed, including at the Browns Ferry nuclear plant and at coal plants in the Tennessee Valley Authority system (Kimmell and Vail 2009).
- The Tennessee Valley Authority reported that it has curtailed operations at some of its operating nuclear plants due to drought because of temperature limits in the receiving waters below cooling water discharge pipes (Weiss 2008, Kimmell and Vail 2009).
- In 2003, rising water temperatures forced German authorities to close a nuclear power plant and reduce output at two others (AFP 2003), and high temperatures and low river levels forced the French government to shut down 4,000 megawatts of nuclear generation capacity (The Guardian 2003).
Despite these concerns, water and energy policies are rarely integrated. Federal policies are being developed with little understanding or concern about the impacts on water resources. In particular, the federal government, through subsidies for corn production, has massively increased the production of ethanol, with little concern for the water supply and quality implications of this policy. Similarly, efforts to promote “clean” coal have ignored the water- intensity of capturing carbon. Likewise, most water managers are pursuing water-supply options such as desalination or interbasin transfers with little concern about the energy implications of their water management decisions. A number of new trends, including rising electricity demands, the application of carbon capture and storage technologies, and the pursuit of increasingly energy-intensive water-supply options, suggest that the conflict between energy and water resources might intensify in coming years and pose a serious risk to the future availability and quality of our nation’s water and energy resources. In combination, these concerns and new trends highlight the need to better integrate water and energy policy.
The disconnect between water and energy policy is driven in large part by the failure of water and energy practitioners to engage with and fully understand one another. Each has been working within their own silo and is only aware of one another when conflict arises, such as when water availability constrains energy production or energy prices affect the financial stability of the water provider. This analysis offers some new insights into the water implications of electricity generation. Transportation fuels are not covered here, although we note that the water implications of transportation fuels are of growing concern due to a shift toward domestic fuel sources, especially biofuels. We also do not address the water implications of extracting and processing the primary fuels used to generate electricity, such as hydraulic fracturing, oil shale production, or other segments of the energy fuel cycle. Some of these impacts will be addressed in later work.
Here, we focus on current and projected electricity generation within the Intermountain West, which is the area bound by the Rocky Mountains in the East and the Sierra Nevada and Cascade Mountains in the West (Figure 1). States entirely or partially within this region include Washington, Oregon, Idaho, Montana, Wyoming, Nevada, Utah, Colorado, Arizona, New Mexico, and California. We note that water and energy concerns are not limited to the West, and examples of water-energy hotspots can be found throughout the United States. However, the Intermountain West is of particular interest for this study because it has a growing population (and demand for energy and water), a diverse fuel mix for power generation, and existing water resource constraints that are expected to worsen.
We divide the report into four sections. Section 1 provides a brief introduction to how electricity is generated in the Intermountain West, and estimated water use for that generation. In Section 2, we provide examples of how water
availability has constrained the operation and siting of power plants in the region and how climate change and continued population growth are projected affect water availability. In Section 3, we analyze the future requirements associated with six different electricity-generation scenarios. In Section 4, we discuss future research needs, including the impacts of climate change on the water requirements for electricity generation and the water requirements for fuel extraction and processing. Finally, we conclude with a set of recommendations for reducing the water-related risks of energy generation.
Conclusions
Water scarcity affects energy production.
Sustainable water and energy use requires integrated study and management.
Under a business-as-usual approach, water resource challenges are likely to intensify throughout the Intermountain West.
Electricity can be generated in the Intermountain West using less water, especially with the adoption of energy-efficiency improvements and dry cooling systems and greater reliance on renewables.
Extracting fuels for energy production has a water cost that must be evaluated.
Climate change will have major implications for water resources and electricity in the Intermountain West.
The impacts of climate change on water resources are already evident in the Intermountain West, including less precipitation and runoff, an earlier snowmelt, and more frequent and intense droughts. Climate models indicate that these impacts will accelerate, particularly if efforts to reduce greenhouse gas emissions continue to be delayed. Climate change will also have major implications for electricity production and use across the Intermountain West, which will, in turn, affect water resources. Warmer temperatures reduce the efficiency of thermal power plants and of transmission and distribution lines. More power will need to be generated, and more water withdrawn and consumed, to offset these efficiency losses. Likewise, reductions in hydropower generation and increases in electricity demand associated with warmer temperatures will increase demand for additional power generation and as a result, likely increase water withdrawals and consumption. Technologies that have been proposed to mitigate climate change, such as carbon capture and storage, might create additional demands on water resources. These impacts are not typically integrated in current electricity analyses; additional analysis is needed to better understand how climate change will affect electricity generation and ultimately water resources.
The production of electricity affects water quality and human and environmental health.
Recommendations
Improve data, information, and education on impact of energy sector on water resources.
Water and energy analysts are often frustrated by the lack of available data on the water use and consumption of energy systems. In a recent report, the Government Accountability Office (GAO) outlines some of the major shortcomings of federal data-collection efforts on water availability and use as they relate to planning and siting energy facilities (2009). The USGS, for example, collects data on water withdrawals by power plants but not water consumption.3 Streamflow gauges, which provide information on water availability, are disappearing. The EIA does not collect data on the use of advanced cooling technologies. No agency collects data on the use of alternative water sources, such as recycled water, for power production. Few data are available on the water-quality impacts of energy production, from energy extraction to generation. Many of these shortcomings are a result of budget cuts. State and federal agencies must enhance data collection and reporting capacities.
Accelerate efficiency improvements.
Improvements in water and energy efficiency can help meet the needs of a growing population, reduce or eliminate the need to develop capital-intensive infrastructure, and provide environmental benefits. Additionally, conservation and efficiency promote both water and energy security by reducing vulnerability to limits on the availability of these resources.
Promote renewable energy systems.
Shifting from conventional fossil fuels to less water-intensive renewable energy sources would reduce the water-intensity of the electricity sector, among other environmental benefits. This, in turn, would help reduce pressure on limited water resources and reduce the electricity sector’s vulnerability to water-supply constraints.
Establish cooling-technology requirements.
Prior to 1970, most thermoelectric plants were built with once-through cooling systems. New requirements set by the Environmental Protection Agency under Section 316(b) of the Clean Water Act have made permitting requirements for these cooling systems more stringent. Additionally, in regions with limited water resources, plant operators have, out of necessity, moved away from water-intensive cooling technologies. Federal and state governments should continue to tighten water-cooling technology requirements through federal and state permitting processes. As many of the power plants in the Intermountain West are already in compliance with 316(b) modifications, they must be motivated to further reduce their water impacts by moving to dry and hybrid cooling and other regionally appropriate technologies.
Promote switching to alternative water sources.
Alternative water sources can reduce freshwater requirements for electricity generation. Recycled municipal wastewater, for example, is a reliable water source that is available in relative abundance across the United States. In 2007, however, only 57 power plants, most of which were located in California, Florida, and Texas, were using treated municipal wastewater (ANL 2007), suggesting that its use could be dramatically expanded and help reduce pressure on freshwater systems. Other alternative water sources include produced water from oil and gas wells, mine pool water, and industrial process water.
Expand research and development efforts.
A number of strategies are available to reduce the tension between water and energy management. Key areas for research and development include technologies and management practices to promote the use of alternative water sources, including produced water, brackish groundwater, and municipal wastewater; application of dry and hybrid-cooling technologies for power plants; and improvements in power plant thermal efficiency.
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