ENERGY-WATER 

NEXUS

Coordinated Federal 

Approach Needed to 

Better Manage Energy 

and Water Tradeoffs

Report to the Ranking Member, 

Committee on Science, Space, and 

Technology, House of Representatives

September 2012

GAO-12-880

United States Government Accountability Office

GAO
United States Government Accountability Office

Highlights of GAO-12-880, a report to the 

Ranking Member, Committee on Science, 

Space, and Technology, House of 

Representatives 

September 2012

ENERGY-WATER NEXUS

Coordinated Federal Approach Needed to Better 

Manage Energy and Water Tradeoffs

Why GAO Did This Study

Water and energy are inextricably 

linked and mutually dependent, with 

each affecting the other’s availability. 

Since 2009, GAO has issued five 

reports on the interdependencies 

between energy and water. These 

reports have shown that a 

considerable amount of water is used 

to cool thermoelectric power plants, 

grow feedstocks and produce biofuels, 

and extract oil and natural gas. Some 

of these sources of energy may also 

negatively affect water quality. In 

addition, developing oil and gas 

resources can produce wastewater—

known as “produced water”—that must 

be managed or treated. Conversely, 

significant amounts of energy are 

needed to extract, transport, treat, and 

use water in urban areas.

GAO was asked to identify key energywater nexus issues that Congress and 

federal agencies need to consider 

when developing and implementing 

national policies for energy and water 

resources. To conduct this work, GAO 

systematically reviewed its five reports 

to identify key nexus issues. GAO also 

used a content analysis of related

literature and interviews with 

specialists to validate these themes.

What GAO Recommends

GAO is recommending that DOE take 

the actions necessary to establish a 

program to address the energy-water 

nexus, with involvement from other 

federal agencies, as described in the 

Energy Policy Act of 2005. DOE 

agreed with the recommendation and 

stated that it will work with other 

federal agencies and experts to 

implement it. 

What GAO Found

As GAO’s past work has shown, and other studies and specialists have 

confirmed, there are a number of key energy-water nexus issues that Congress 

and federal agencies need to consider when developing and implementing 

national policies for energy and water resources. Specifically:

• Location greatly influences the extent to which energy and water affect one 

another. For example, as GAO reported in November 2009, the impact of 

increased biofuel production on water resources will depend on where the 

feedstock is grown and whether or not irrigation is required. Consequently, it 

is important for Congress and federal agencies to consider the effects that 

national energy production and water use policies can have at the local level. 

• Although technologies and approaches exist to reduce the impact of energy 

development on water resources and reduce the energy needed to move, 

use, and treat water, their widespread adoption is inhibited by barriers such 

as economic feasibility and regulatory challenges. In implementing energy 

and water policies, Congress and federal agencies will also need to be 

cognizant of the barriers when deciding whether to promote the adoption of 

these technologies and approaches. 

• Making effective policy choices will continue to be challenging without more 

comprehensive data and research. GAO’s past work has identified the need 

for more data and research related to the energy-water nexus, for example, 

to better understand hydrological processes, including aquifer recharge rates 

and groundwater movement. In the absence of such data and research, 

developing and implementing effective policies could continue to be a 

challenge for Congress and federal agencies. 

• Improved energy and water planning will require better coordination among 

federal agencies and other stakeholders. GAO’s work has demonstrated that 

energy and water planning are generally “stove-piped,” with decisions about 

one resource made without considering impacts to the other resource. 

Improved planning will require federal agencies to work with one another and 

other stakeholders, such as state and local agencies, academia, industry, 

and environmental groups. Congress and some agencies have taken steps 

to improve coordination, but these actions are incomplete or in their early 

stages. For example, in the Energy Policy Act of 2005, Congress directed the 

Department of Energy (DOE) to establish a federal program to address the 

energy-water nexus, but DOE has not done so.

• Uncertainties affecting energy and water resources cannot be ignored 

because they could significantly affect the future supply and demand of both 

resources. For example, specialists GAO talked to and literature GAO 

reviewed identified climate change, population growth, and demographic 

shifts as significant uncertainties expected to exacerbate the challenges 

associated with managing both the supply and demand of water and energy. 

These uncertainties must, therefore, be accounted for when developing 

national policies that affect both of these resources.

View GAO-12-880. For more information, 

contact Anu K. Mittal at (202) 512-6100 or 

mittala@gao.gov or Frank Rusco at (202) 512-

3841 or ruscof@gao.gov. 
Page i GAO-12-880 Energy-Water Nexus 

Letter 1 

Background 4

Key Issues to Consider When Developing and Implementing 

National Policies for Energy and Water Resources 10

Conclusions 27

Recommendation for Executive Action 27

Agency Comments and Our Evaluation 28

Appendix I Objectives, Scope, and Methodology 30

Appendix II Comments from the Department of Energy 32

Appendix III GAO Contacts and Staff Acknowledgments 34

Figures

Figure 1: Diagram of a Boiler Loop in a Power Plant 5

Figure 2: Biofuels Life Cycle 6

Figure 3: Key Stages of the Urban Water Life Cycle 9

Abbreviations

DOE Department of Energy

EIA Energy Information Administration

EPA Environmental Protection Agency

Interior Department of the Interior

RD&D research, development, and demonstration

USDA U.S. Department of Agriculture

USGS U.S. Geological Survey

Contents

This is a work of the U.S. government and is not subject to copyright protection in the 

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necessary if you wish to reproduce this material separately.
Page 1 GAO-12-880 Energy-Water Nexus 

United States Government Accountability Office 

Washington, DC 20548

September 13, 2012

The Honorable Eddie Bernice Johnson

Ranking Member

Committee on Science, Space, and Technology

House of Representatives

Dear Ms. Johnson:

Water and energy are inextricably linked and mutually dependent, with 

each affecting the other’s availability. Water is needed for energy 

development and generation, and energy is required to supply, use, and 

treat drinking water and wastewater. Water and energy are also essential 

to our health, quality of life, and economic growth, and consequently the 

demand for both of these resources continues to rise. Water is 

increasingly in demand to meet the needs of the public, farms, and 

industries, and for recreation and wildlife; and while freshwater flows 

abundantly in many of our nation’s lakes, rivers, and streams, it is a 

dwindling resource in many parts of the country. Similarly, energy is 

increasingly in demand to support manufacturing and transportation, 

among other things. As the demand for water increases, the demand for 

energy is similarly expected to grow. While the growth rate in energy 

consumption in the United States has slowed over time, overall 

consumption continues to rise, with estimates from the Department of 

Energy’s (DOE) Energy Information Administration (EIA) showing an 

expected growth of 10 percent between 2010 and 2035. To help meet this 

increased energy demand, domestic energy production is rising, along 

with its associated water usage. According to the Congressional 

Research Service, the energy sector has been the fastest growing water 

consumer in the United States in recent years and is projected to account 

for 85 percent of the growth in domestic water consumption between 

 
 

Page 2 GAO-12-880 Energy-Water Nexus 

2005 and 2030.1

Since 2009, we have issued five reports on the interdependencies that 

exist between energy and water.

This increase in water use associated with energy 

development is being driven, in part, by rising energy demand, increased 

development of domestic energy, and shifts to more water-intense energy 

sources and technologies.

2 These reports have shown that a 

considerable amount of water is used to cool thermoelectric power 

plants,3 grow feedstocks and convert them into biofuels, and extract oil 

and natural gas from geologic formations. Oil shale development would 

also require a great deal of water if commercial production of this energy 

source becomes economically feasible in the future.4

 

1

Water consumption refers to the portion of the water withdrawn that is no longer available 

to be returned to a water source, such as when it has evaporated. Energy production 

(which includes biofuel production), together with thermoelectric power, are the second 

largest consumer of water in the United States, accounting for approximately 11 percent of 

water consumption in 2005. Irrigation was the largest consumer, at approximately 74 

percent. (Elcock, D., “Future U.S. Water Consumption: The Role of Energy Production,” 

Journal of the American Water Resources Association, vol. 46, no. 3 (2010): 447-460.). 

However, according to the U.S. Geological Survey, in terms of water withdrawal, 

thermoelectric power was the largest source of water withdrawals (49 percent) in 2005, 

followed by irrigation at 31 percent. Water withdrawal refers to water removed from the 

ground or diverted from a surface water source, such as an ocean, river, or lake.

Some of these 

2

GAO, Energy-Water Nexus: Improvements to Federal Water Use Data Would Increase 

Understanding of Trends in Power Plant Water Use, GAO-10-23 (Washington, D.C.: Oct. 

16, 2009); GAO, Energy-Water Nexus: Many Uncertainties Remain about National and 

Regional Effects of Increased Biofuel Production on Water Resources, GAO-10-116 

(Washington, D.C.: Nov. 30, 2009); GAO, Energy-Water Nexus: Amount of Energy 

Needed to Supply, Use, and Treat Water Is Location-Specific and Can Be Reduced by 

Certain Technologies and Approaches, GAO-11-225 (Washington, D.C.: Mar. 23, 2011); 

GAO, Energy-Water Nexus: A Better and Coordinated Understanding of Water Resources 

Could Help Mitigate the Impacts of Potential Oil Shale Development, GAO-11-35 

(Washington, D.C.: Oct. 29, 2010); and GAO, Energy-Water Nexus: Information on the 

Quantity, Quality, and Management of Water Produced during Oil and Gas Production, 

GAO-12-156 (Washington, D.C.: Jan. 9, 2012).

3

Thermoelectric power plants use a fuel source—for example, coal, natural gas, nuclear 

material such as uranium, or the sun—to boil water to produce steam. The steam turns a 

turbine connected to a generator to produce electricity.

4

Production of oil shale requires the heating of rock containing solid organic matter to 

between 650 and 1000 degrees Fahrenheit and injecting water into the formation to 

stimulate the oil to flow. To date, there has been no commercial production of oil shale 

resources, in part, because the energy requirements to heat the rock and the water 

needed to stimulate the flow of oil make the process too costly to compete with other 

sources of oil.
 

Page 3 GAO-12-880 Energy-Water Nexus 

sources of energy—for example, biofuels, which require the use of large 

amounts of fertilizers and pesticides to grow the feedstock—may also 

negatively affect water quality. In addition, development of oil and gas 

resources can produce large volumes of wastewater—known as 

“produced water”—that must be disposed of or treated to allow for its 

reuse. Conversely, significant amounts of energy are needed to extract, 

transport, treat, and use water in urban areas, additionally contributing to 

energy demand. Two of these reports contained recommendations, which 

the agencies generally agreed with and are currently in the process of 

implementing.

In light of the challenges we have identified in increasing the development 

of various domestic energy sources while ensuring they do not have 

detrimental impacts on water availability and quality in the future, you 

asked us to provide an overview of the analysis from our five energywater nexus reports and highlight areas that Congress and federal 

agencies should focus on in setting and implementing water and energy 

policy. Based on a review of our recent work in this area as well as a 

review of published literature and interviews with specialists, this report 

examines key issues for Congress and federal agencies to consider when 

developing and implementing national policies for energy and water 

resources.

To conduct this work, we systematically reviewed our five prior reports on 

the energy-water nexus and identified key issues that affect the 

development and implementation of national policies for energy and water 

resources. To validate these themes, we conducted a content analysis of 

key literature that examines this nexus, including peer-reviewed scientific 

periodicals, government-sponsored research and studies, and reports 

from nongovernmental research organizations. We also included in the 

content analysis interviews with a wide range of specialists whom we 

identified as having expertise related to the energy-water nexus in the 

United States. We selected these specialists using an iterative process, 

soliciting additional names from each person we interviewed. From 

among those identified, we conducted structured interviews with 

specialists who could provide a broad range of perspectives on the 

energy-water nexus, as well as specialists whom we identified during our 

systematic review of studies who have analyzed (1) the energy-water 

nexus in general or (2) particular segments (i.e., water use by 

thermoelectric power plants) of the nexus. These specialists represented 

a variety of organizations, including federal officials; university 

researchers; water and energy industry representatives from groups such 

as the American Water Works Association and the Electric Power 
 

Page 4 GAO-12-880 Energy-Water Nexus 

Research Institute; and nongovernmental organizations, such as the 

Pacific Institute.5

We conducted this performance audit from March 2012 to September 

2012, in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.

Representatives from federal agencies included officials, 

scientists, and researchers from DOE’s national laboratories and EIA, the 

U.S. Department of Agriculture (USDA), the Department of the Interior’s 

(Interior) U.S. Geological Survey (USGS), and the Environmental 

Protection Agency (EPA). We also reviewed federal laws and regulations 

as applicable. To conduct the content analysis of key literature and 

information gathered through interviews with specialists, we reviewed 

each study and interview and coded statements within them based on 

themes we developed from the GAO reports. For the purposes of 

reporting the results of our analysis, we used the following categories to 

quantify the literature and responses of specialists: “some” refers to at 

least two studies or specialists, “several” refers to at least five studies or 

specialists, and “many” refers to eight or more studies or specialists. 

Appendix I discusses our scope and methodology in more detail.

As our series of reports on the energy-water nexus has shown, many 

aspects of energy development and delivery, including resource 

extraction, refining and processing, generation, storage, and 

transportation, can affect water resources. Conversely, supplying water in 

an urban setting requires energy to extract, treat, and supply water to 

consumers. Specifically, our prior work related to the energy-water nexus 

focused on the following five areas:

• Thermoelectric power plants. In 2007, around three-fourths of the 

United States’ electricity-generating capacity consisted of

thermoelectric power plants, which rely heavily on water for cooling, 

 

5

The Pacific Institute conducts interdisciplinary research and partners with stakeholders to 

produce solutions that advance environmental protection, economic development, and

social equity in California, nationally, and internationally.

Background
 

Page 5 GAO-12-880 Energy-Water Nexus 

as discussed in our October 2009 report.6 Thermoelectric power 

plants use a fuel source—including coal; natural gas; nuclear material, 

such as uranium; or the sun—to boil water to produce steam, which is 

used to turn a turbine connected to a generator that makes electricity. 

As shown in figure 1, the water used to make steam (boiler water) 

generally circulates in a closed loop. That is, the steam from the boiler 

water is cooled and converted back to liquid water—referred to as 

condensing—in a device called a condenser and, finally, moved back 

to the heat source to again make steam. In typical thermoelectric 

plants, the water used to cool and condense the steam––known as 

cooling water––flows from a separate source. Power plants can use 

various types of water for cooling—such as freshwater or saline 

water—and different water sources, including surface water; 

groundwater; and alternative water sources, such as reclaimed water 

from industrial uses.

Figure 1: Diagram of a Boiler Loop in a Power Plant

 

6

GAO-10-23. 
 

Page 6 GAO-12-880 Energy-Water Nexus 

• Biofuels. In recent years, the federal government has increasingly 

encouraged the use of biofuels and other alternatives to petroleum in 

response to concerns over the nation’s dependence on imported oil, 

climate change, and other issues.7 As we reported in November 

2009,8 water supply and quality can be affected by many stages of the 

biofuel life cycle, as can similar practices devoted to food production 

(see fig. 2). To cultivate feedstocks, crops can be either rainfed, with 

all needed water provided by natural precipitation and soil moisture, or 

irrigated, with at least some portion of these water requirements met 

through water applied from surface or groundwater sources. Water is 

also used in the fermentation, distillation, and cooling processes of 

converting the feedstock into biofuel.

Figure 2: Biofuels Life Cycle

 

7

The Energy Policy Act of 2005 created a Renewable Fuel Standard that generally 

required gasoline and diesel in the United States to contain renewable fuels, such as 

ethanol and biodiesel. Pub. L. No. 109-58 § 1501 (2005). The Energy Independence and 

Security Act of 2007 expanded the Renewable Fuel Standard. Pub. L. No. 110-140 § 201 

(2007).

8

GAO-10-116. 
 

Page 7 GAO-12-880 Energy-Water Nexus 

• Oil shale. As we reported in October 2010,9

• Produced water. The process of producing oil and gas yields several 

byproducts, including produced water that must be managed as part 

of the oil and gas operation’s waste stream. Produced water may 

contain a variety of contaminants, including naturally occurring 

radionuclides, salts, and chemicals injected into some wells to help 

extract the oil and gas. In January 2012,

it may become 

economically feasible to develop the vast amounts of oil generated 

from U.S. oil shale—a sedimentary rock containing solid organic 

material that converts into a type of crude oil when heated—and, if it 

does, this source could help satisfy the nation’s future oil demands. 

Current known processes for producing oil from oil shale deposits, 

however, are not economically feasible—the oil costs more to produce 

than it could be sold for. However, if oil prices were to rise high 

enough to make oil shale production cost effective, and if other 

challenges associated with developing this resource were resolved, 

we reported that producing oil from oil shale could require large 

amounts of water. As a result, while water is expected to be available 

for the initial development of an oil shale industry, the ultimate 

potential size of any industry might be limited by water availability, 

among other things. Furthermore, in the absence of effective 

mitigation measures, water resources could be affected by ground 

disturbances caused by the construction of roads and production 

facilities; the withdrawal of water from streams and aquifers for oil 

shale operations; underground mining and extraction; and the 

discharge of waters produced from or used in oil shale operations.

10 we reported that most 

produced water is reinjected into wells designed for this purpose 

because it requires little or no treatment and is often the least costly 

option,

11

• Energy for water supply. Providing drinking water and wastewater 

services to an urban environment involves extracting, moving, and 

but some produced water is deemed to be clean enough 

without extensive treatment to be used for other purposes, such as 

agricultural or livestock operations. However, if produced water is not 

appropriately managed or treated, contaminants in the water may 

present human health and environmental risks.

 

9

GAO-11-35. 

10GAO-12-156. 

11According to federal estimates, more than 90 percent of all produced water is managed 

through underground injection.
 

Page 8 GAO-12-880 Energy-Water Nexus 

treating water. As we described in our March 2011 report,12 energy 

plays a crucial role throughout this life cycle. Energy is needed to 

extract raw water from the source—such as lakes, rivers, and 

underground aquifers—and convey it to the facility where it is treated 

and distributed as drinking water to customers. Furthermore, energy is 

needed to circulate, pressurize, and heat water for use inside 

households and businesses and for outdoor water-related uses by 

customers, such as for watering lawns. Finally, energy is required to 

convey wastewater to treatment facilities, treat the wastewater, and 

discharge the treated effluent into a receiving body of water. (See fig. 

3 for the key stages in the water life cycle.)

 

12GAO-11-225. 
 

Page 9 GAO-12-880 Energy-Water Nexus 

Figure 3: Key Stages of the Urban Water Life Cycle
 

Page 10 GAO-12-880 Energy-Water Nexus 

Our past energy-water nexus work has identified a number of key issues 

for Congress and federal agencies to consider when developing and 

implementing national policies for energy and water resources. These 

include (1) the varying local impacts of federal energy and water policy 

choices, (2) the mitigation of barriers to using innovative technologies and 

approaches, (3) the challenge of making effective policy choices in the 

absence of more comprehensive data and research, (4) the importance of 

coordination among governmental and nongovernmental stakeholders in 

order to improve planning, and (5) the attention to the uncertainties that 

affect energy and water resources when setting and implementing federal 

policies for these resources. The importance of these issues was also 

emphasized by the literature that we reviewed and the specialists we 

spoke with.

Our past work, as well as the literature that we reviewed and the 

specialists we spoke with, emphasized that the amount and quality of 

surface and groundwater used to produce energy resources, as well as 

the amount and quality of water produced during oil and gas extraction, 

varies considerably across different locations, and this variation greatly 

influences how energy and water affect one another. Consequently, we 

believe that it will be important for Congress and federal agencies to 

consider the effects that national policies related to energy production and 

water use can potentially have at the local level. For example:

• As we reported in November 2009 on biofuels,13

• Similarly, because both water and energy permitting and regulations 

vary by state, the extent to which these two resources will affect each 

the impact of 

increased biofuel production on water resources will depend on where 

the feedstock is grown and whether or not irrigation is required. 

Specifically, some of the largest increases in corn acres for biofuel 

production are projected to occur in the Northern Plains, which relies 

on irrigation and is already water-constrained. Furthermore, parts of 

the region draw heavily from the Ogallala Aquifer, where water 

withdrawals for agriculture and other uses are already greater than 

the natural recharge rate from precipitation. As a result, developing 

national policies that encourage additional biofuel production could 

have a greater impact on local water resources in certain areas than

in others.

 

13GAO-10-116. 

Key Issues to 

Consider When 

Developing and 

Implementing 

National Policies for 

Energy and Water 

Resources

Federal Energy and Water 

Policy Choices Can Have 

Varying Local Impacts
 

Page 11 GAO-12-880 Energy-Water Nexus 

other depends on the state in which the development of these 

resources occurs. For example, as we reported in October 2009 on 

thermoelectric power plants,14

• In our January 2012 report on produced water,

some states, such as Arizona and 

Georgia, require thermoelectric power plant developers to obtain 

water use permits, while Alabama does not require such permits. As a 

result, the further expansion of the thermoelectric power industry in 

certain states can be more challenging than in others, in part, 

because of the need to meet state permitting and regulatory 

requirements for water use at those locations.

15

• As some of our energy-water nexus reports have documented, the 

energy needed to transport water is greatly influenced by locationspecific factors like topography, distance, and the type and quality of 

the water source. For example, in our March 2011 report on energy 

for water supply,

we identified 

significant variations in the amount of water produced by oil and gas 

wells on the basis of location-related differences, such as variation in 

local or regional geology. For example, wells in the Barnett Shale 

formation in Texas, which is generally known to be a “wetter” 

formation than the Marcellus Shale formation in the Northeast, 

typically produce 3 to 4 times more water than shale gas wells in the 

Marcellus. We noted that even within the same formation, produced 

water volumes and quality can vary greatly. The quality of produced 

water also varies considerably across different formations. Some 

produced water can be used for livestock or agricultural applications 

because the water is generally of high enough quality to not require 

extensive treatment, while other produced water may not be used in 

this way because it is of poor quality; for example, it may contain 

contaminants, such as naturally occurring radionuclides, salts, metals, 

oils, and production chemicals. Such water is typically re-injected into 

wells designed for this purpose largely because it is less costly to do 

so than to treat the water sufficiently to enable other uses. It will be 

important for federal regulators to be cognizant of these locationrelated variations in the quantity and quality of produced water and 

their related disposal and treatment implications when they develop 

national regulatory policies for oil and gas development.

16

 

14

we reported that because pumping water accounts 

GAO-10-23. 

15GAO-12-156. 

16GAO-11-225. 
 

Page 12 GAO-12-880 Energy-Water Nexus 

for 80 to 90 percent of the energy used to supply drinking water in 

some systems, moving water over hills and long distances can 

increase the level of energy consumption significantly. Consequently, 

when developing national policies for energy and water, policymakers 

need to consider the potential energy costs that can be associated 

with the transport and distribution of water in various settings.

In addition, the literature we reviewed and several specialists we spoke 

with stated that water is generally undervalued in the United States, and 

its prices do not reflect the true cost of providing the resource, which can 

result in its overuse. Some specialists also told us that the extent to which 

water is undervalued varies by location, with water-scarce areas being 

more likely to value their water resources. Furthermore, as one specialist 

told us, the price customers are charged for the water they consume does 

not reflect all of the costs required to extract, treat, and supply the water. 

Therefore, consumers may be unaware of the true costs of water and 

more likely to waste it, which in turn leads to unnecessary energy use to 

produce more water.

Our past work, supported by other literature we reviewed and specialists 

we spoke with, has identified a variety of technologies and approaches 

that can reduce the impact of energy development on water resources, as 

well as the energy use associated with water supply, use, and treatment. 

However, we also identified a number of significant barriers that Congress 

and federal agencies will need to be cognizant of when deciding whether 

to promote and ensure the more widespread adoption of these 

technologies and approaches, as the following examples illustrate:

• As we reported in October 2009 on thermoelectric power plants,17

 

17

advanced cooling technologies, such as dry cooling that uses air 

rather than water for cooling, can reduce water use at thermoelectric 

power plants. However, these technologies may incur “energy 

penalties”––that is, the energy required to power the cooling systems 

may reduce the plant’s net energy production to a greater extent than 

traditional cooling systems, potentially leading to higher electricity 

prices. In addition, advanced cooling technologies can have capital 

costs that are up to 4 times as expensive as traditional cooling 

systems, and they may operate less efficiently in dry, arid locations, 

GAO-10-23. 

Realizing the Benefits of 

Innovative Technologies 

and Approaches Also 

Depends on Mitigating 

Barriers to Their Use
 

Page 13 GAO-12-880 Energy-Water Nexus 

among other concerns. As a result, policymakers seeking to 

encourage the adoption of these technologies by thermoelectric 

power plants with the goal of reducing water use will also have to 

consider ways to increase their economic feasibility and reduce their 

costs to plant operators and electricity consumers.

• As we reported in our 2009 reports on thermoelectric power plants 

and on biofuels,18

• As we discussed in our 2009 report on biofuels,

the use of alternative water sources, such as 

treated effluent or groundwater unsuitable for drinking or irrigation, 

can reduce dependence on freshwater at thermoelectric power plants 

and biofuel refineries but may present drawbacks, such as adverse 

effects on cooling equipment, the need for expensive treatment 

equipment, and regulatory challenges. For example, power plants 

must comply with a number of water quality and air regulations, and 

the presence of certain pollutants in alternative water sources can 

make compliance more challenging. Furthermore, the physical layout 

of power plants and biorefineries may need to be changed to 

accommodate the use of alternative water sources. Consequently, if 

the goal of national water and energy policy is to encourage the use of 

alternative water sources instead of freshwater sources for the 

production of energy, then it would also be important to focus on 

developing better information about the tradeoffs of using alternative 

water sources.

19

 

18

agricultural 

conservation practices can reduce the potential effects of increased 

biofuel feedstock cultivation on water resources, but there are barriers 

to their widespread adoption. For example, conservation tillage 

practices—such as “no-till” systems or reduced tillage systems, where 

the previous year’s crop residues are left on the fields and new crops 

are planted directly into these residues—can help reduce soil erosion. 

Research conducted by USDA has shown a substantial reduction in 

cropland erosion since 1985, when incentives were put in place to 

encourage the adoption of conservation tillage practices. However, 

many farmers do not have the expertise or training to implement 

certain agricultural practices, and some practices may be less suited 

for some places. For example, farmers usually need a year or more of 

experience with reduced tillage before they can achieve the same 

crop yields they had with conventional tillage, and the amount of 

agricultural residue that can be removed varies by region and even by 

GAO-10-23. GAO-10-116. 

19GAO-10-116. 
 

Page 14 GAO-12-880 Energy-Water Nexus 

farm. Consequently, a national policy encouraging additional biofuel 

production would benefit from continued education and outreach 

provided by the federal government to help farmers better understand 

the advantages of adopting such conservation practices.

• More energy-efficient equipment could reduce the energy required to 

move and treat water, but the adoption of such technology may be 

hindered by the costs of retrofitting water treatment facilities and other 

obstacles, as we discussed in our March 2011 report on energy for 

water supply.20

• As we also reported in March 2011 on energy for water supply,

For example, the use of variable frequency drives at 

water treatment facilities, which allow operators to accommodate 

variations in water flows and run pumps at lower speeds, can reduce 

energy use by 5 to 50 percent or more. However, installing the drives 

can be cost prohibitive, and they are not necessarily well suited in all 

instances, such as when water flow is relatively constant. Therefore, 

federal policies to reduce energy consumption would also have to 

recognize the challenges faced by treatment facility operators in 

reducing energy consumption at their facilities and explore 

opportunities to assist them with this transition.

21

water conservation is an approach to reducing the energy needed for 

the urban water lifecycle. Specifically, decreased customer water use 

could directly translate into energy savings, and water conservation 

also reduces the amount of energy used to convey, treat, and 

distribute water to customers. Similarly, energy conservation 

measures would also decrease water use. Therefore, when 

considering the development of additional energy and water 

conservation measures, policymakers may want to consider not only 

those that can be used by utilities but also those that can be used by 

consumers.

Our past work, supported by other literature we reviewed and specialists 

we spoke with, identified a dearth of key data and research related to 

energy and water. We believe that developing and implementing effective 

policies will continue to be a challenge for Congress and federal agencies 

in the absence of such data and research. Support for this data 

development will be essential to improved decisionmaking, as the 

following examples demonstrate:

 

20GAO-11-225. 

21GAO-11-225. 

Making Effective Policy 

Choices Will Continue to 

Be a Challenge in the 

Absence of 

Comprehensive Data and 

Research
 

Page 15 GAO-12-880 Energy-Water Nexus 

• As a number of our energy-water nexus reports have found, data on 

the availability of freshwater and alternative water supplies are limited, 

and the lack of such data makes it challenging to fully assess the 

impact that particular energy policy choices will have on water 

resources. Several specialists we spoke with raised concerns that 

such data will be even harder to obtain in light of decreased funding 

for USGS’s monitoring efforts. Specifically, as we discussed in our 

October 2009 report on thermoelectric power plants,22 some state 

regulators and water experts expressed concern about a reduction in 

the number of streamflow gauges, which they said may make 

evaluating trends in water availability and water planning more difficult 

in the future. Without accurate data on water availability, water 

planning and decisions involving allocation of water resources—

including power plant permitting decisions—may be less informed, 

according to regulators and experts we spoke with. In addition, our 

past work and some specialists we spoke with identified a need for 

more data on the quantity and quality of existing water supplies. For 

example, in our October 2010 report on oil shale,23

• Additional research and data on hydrological processes are needed. 

Our reports and discussions with specialists identified a number of 

areas needing more research, including the interactions between 

groundwater and surface water, to understand the possible transport 

of contaminants from energy development, aquifer recharge rates and 

groundwater movement, and precipitation runoff, as well as how much 

water is available for and used by crops.

we reported that 

data on the water quantity and quality baseline conditions of 

groundwater and surface water supplies are not sufficient for 

monitoring the potential impacts of oil shale development in the future. 

We believe that effective decisions about withdrawing water from 

existing supplies for energy production cannot be made without first 

understanding how much water is actually available and the quality of 

these supplies, and that the federal government plays a key role in 

generating these kinds of important data.

24 For example, as we 

previously discussed in our November 2009 report on biofuels,25

 

22GAO-10-23. 

23GAO-11-35. 

24An aquifer is a geologic formation or structure that stores and/or transmits water, such 

as to wells and springs. Aquifer recharge is the process by which water is added to an 

aquifer, such as through rainfall that seeps into the ground.

25GAO-10-116. 
 

Page 16 GAO-12-880 Energy-Water Nexus 

several specialists and agency officials have stated that research into 

hydrogeological processes is needed to understand the rate at which 

aquifers are replenished and the impacts of increased biofuel 

production on those aquifers. Although research suggests there 

should be sufficient water resources to meet future feedstock 

production demands at a national level, increases in this production 

may lead to significant water shortages in certain regions. Even in 

typically water-rich states, such as Iowa, concerns have arisen over 

the effects of increased biofuel production, and research is needed to 

assess the hydrology and quality of a state’s aquifers to help ensure 

the state is on a path to sustainable biofuel production. Consequently, 

not only is there a need for baseline data on existing water supplies, 

but there is also a need for more information on how quickly such 

supplies are replenished and how they are affected by contaminants, 

so that as Congress and federal agencies are developing and 

implementing national energy policies they can ensure that they are 

considering sustainable water supplies for energy production over the 

long term.

• Research to determine how new technologies will affect the energywater nexus has not been conducted to demonstrate the effects of 

these technologies at commercial scales. For example, according to 

many specialists we spoke with and some studies we reviewed, 

implementing carbon capture and sequestration technologies would 

consume large amounts of freshwater and could affect the quality of 

nearby water supplies,26 but the extent of such effects is not well 

known.27 In the case of biofuels, next generation feedstocks for 

biofuels—such as algae or cellulosic materials, including stalks, 

stems, branches, and leaves—have the potential for fewer negative 

effects on water resources, but the magnitude of these effects 

remains largely unknown because these feedstocks have not yet 

been grown on a commercial scale. For example, as we discussed in 

our November 2009 report on biofuels,28

 

26Carbon capture and sequestration technologies separate and capture carbon dioxide 

from other gases produced when combusting or gasifying coal, compress it, then transport 

it to underground geologic formations where it is injected for long-term storage.

conversion of cellulosic 

27In 2010, EPA promulgated a rule establishing minimum requirements under the Safe 

Drinking Water Act for the underground injection of carbon dioxide for the purpose of 

geologic sequestration. According to EPA officials, they are in the process of 

implementing the rule, and they believe the rule is fully protective of underground sources 

of drinking water. 

28GAO-10-116. 
 

Page 17 GAO-12-880 Energy-Water Nexus 

feedstocks is expected to use less water compared with conventional 

feedstocks in the long run. However, commercial-scale production has 

not yet been demonstrated; therefore, any estimates on water use by 

cellulosic biorefineries are simply projections at this time. Focusing 

only on certain potential benefits of new technologies without 

understanding the full impacts of such technologies can have 

unintended consequences, a concern voiced by several of the 

specialists we spoke with. Therefore, along with federal support for 

data and research into new technologies it will also be essential for 

Congress and federal agencies to support data and research to gain a 

better understanding of how adopting these technologies will affect 

both energy and water resources as well as the environment more 

broadly.

• Data on water or energy use by existing technologies and research 

into how to optimize these technologies is needed, according to our 

past reports and specialists we spoke with. For example, as we 

previously discussed in our November 2009 report on biofuels,29

In addition, research into and development of better models and decision 

support tools would help inform decisions related to the energy-water 

nexus, according to some reports we reviewed and specialists we spoke 

research into biorefinery cooling systems could help reduce the water 

used during conversion of feedstocks into biofuels. According to DOE 

officials, research and development is also needed to improve hybrid 

wet-dry cooling systems for thermoelectric power plants. In addition, 

several specialists told us that analyses are needed on the amount of 

energy or water used throughout the entire life cycle of supplying 

water and producing energy. For example, in the case of 

thermoelectric power, a life-cycle analysis would look beyond just the 

water consumed in cooling towers and would assess the amount of 

water needed to mine, refine, transport, and burn the coal; however, 

such an analysis would require a level of detail beyond that which is 

currently available for water data, according to specialists we spoke 

with. Additional data gathering and research on existing technologies 

can help energy and water suppliers better understand the true 

impacts of existing technologies on energy and water resources and 

consider those impacts in comparison with the potential advantages of 

new technologies. Data gathering and research is another area where 

we believe that federal agencies could play an important role and 

assist with such analyses.

 

29GAO-10-116. 
 

Page 18 GAO-12-880 Energy-Water Nexus 

with. For example, as one specialist told us, while there are many national 

climate change models, regional models are needed to increase the 

accuracy of projections. Efforts are underway to develop downscaled 

models, but data may not be available to populate the models.30 In 

addition, EPA officials told us that the U.S. Global Climate Research 

Program, which coordinates and integrates federal research on global 

environmental changes and their implications for society, is considering 

regional modeling and studies for cross-agency climate change in the 

future; however, these plans are not yet final. In the absence of improved 

models and decision support tools, Congress and federal agencies may 

be making decisions that affect energy and water supplies without fully 

understanding the impact of these decisions.

Our past work, the literature we reviewed, and specialists we spoke with 

noted that, in general, energy and water planning are “stove-piped” and 

frequently split across federal, state, and local levels, which results in 

decision making that does not adequately account for the interactions 

between energy and water. Improved energy and water planning will 

require federal agencies with oversight of these resources to coordinate 

with one another as well as with other stakeholders, such as state and 

local agencies, academia, industry, and environmental groups, as the 

following examples demonstrate:

• Our previous reports have highlighted the need for a better 

understanding of the energy-water nexus, and two of these reports 

recommended that federal agencies collaborate on research and data 

collection efforts related to it. Specifically, in our October 2009 

thermoelectric power plant report,31

 

30 We reported on the need for downscaled climate information in Climate Change 

Adaptation: Strategic Federal Planning Could Help Government Officials Make More 

Informed Decisions, 

we recommended that EIA and 

USGS establish a process for regularly coordinating with each other, 

other federal agencies, and water and electricity industry experts, 

among others, to improve the overall quality of data collected on water 

use from power plants. DOE and Interior generally agreed with our 

recommendation, and both agencies are currently in the process of 

implementing it. Specifically, EIA and USGS have held two meetings 

to discuss such matters. USGS organized the initial meeting in 

GAO-10-113 (Washington, D.C.: Oct. 7, 2009).

31GAO-10-23. 

Coordination among 

Governmental and 

Nongovernmental Entities 

Is Key to Improved 

Planning
 

Page 19 GAO-12-880 Energy-Water Nexus 

November 2010, and EIA hosted the second meeting in March 2012. 

Invitees to the meetings also included representatives from federal 

agencies and national laboratories. USGS is scheduled to host the 

next meeting in October 2012. In addition, in our October 2010 oil 

shale report,32

• Our previous reports recognized that adequately addressing the 

energy-water nexus will require federal agencies to seek input from 

relevant stakeholders outside of the federal government. Specifically, 

we recommended in both our thermoelectric power plant and oil shale 

reports that federal agencies collaborate with entities outside of the 

federal government. In response to the recommendation in our 

October 2009 report on thermoelectric power plants,

we recommended that the Secretary of the Interior 

coordinate with DOE and state agencies with regulatory authority over 

water resources on oil shale data collection and modeling efforts, and 

provide a mechanism for water-related research collaboration and 

results sharing. Interior generally agreed and has begun to take some 

steps to implement the recommendation. Specifically, Interior stated 

that it was working to improve coordination with DOE and state 

agencies with regulatory authority over water resources. The literature 

we reviewed and many specialists we spoke with concurred that 

federal agencies should collaborate to better understand the energywater nexus. As some specialists told us, without such coordination 

and collaboration between federal agencies, it will be difficult to 

ensure that energy-water tradeoffs are properly considered.

33 DOE and 

Interior generally agreed with our recommendation and, as described 

earlier, EIA and USGS have since held two meetings. In addition to 

the federal agencies that participated, nonfederal invitees to the 

meetings included industry groups, such as the Nuclear Energy 

Institute; universities, such as Southern Illinois University; and 

environmental groups, such as The Nature Conservancy. In our 

October 2010 oil shale report,34

 

32

Interior generally agreed with our 

recommendation to collaborate with entities outside of the federal 

government and has begun to take some steps to implement the 

recommendation. Specifically, Interior stated that it was working with 

state agencies that have regulatory authority over water resources. 

The literature we reviewed and many specialists we spoke with also 

GAO-11-35. 

33GAO-10-23. 

34GAO-11-35. 
 

Page 20 GAO-12-880 Energy-Water Nexus 

believed collaboration with stakeholders outside the federal 

government is needed. For example, in its 2006 report to Congress,35

DOE reported that the lack of integrated energy and water planning 

and management has already affected energy production in many 

basins and regions across the country, and that collaboration on 

energy and water resource planning is needed among federal, 

regional, and state agencies, as well as with industry and other 

stakeholders. As some specialists told us, state and local agencies 

are primarily responsible for allocating and managing water 

resources; therefore, energy-water nexus discussions need to involve 

officials from other levels of government. Similarly, public utility 

commissions make energy decisions in many states, and the role of 

these commissions is important to consider when addressing the 

energy-water nexus.36

• Many specialists told us that, because of the stove-piped nature of 

energy and water issues in the federal government, a top-down 

emphasis on collaboration among federal agencies and with other 

groups outside of the federal government is needed. Some specialists 

pointed to a recent memorandum of agreement between three federal 

agencies on unconventional oil and gas research as a good model. 

Specifically, in March 2011, the White House released the Blueprint 

for a Secure Energy Future, a comprehensive plan to reduce 

America’s oil dependence, save consumers money, and make the 

United States the leader in clean energy industries. The Blueprint 

instructed the federal government to conduct research to examine the 

impacts of hydraulic fracturing on water resources. To fulfill this 

Furthermore, as DOE officials noted, many 

political boundaries between states are formed by water bodies. 

Therefore, multiple counties and states can be involved in water 

management decisions, which can lead to conflicts and be an 

impediment to water planning. Because of the various stakeholders 

with a role in managing energy and water, we believe that it will be 

important for federal agencies to improve coordination including with 

their nonfederal partners in order to enhance energy and water 

planning and put the United States on a path that is more sustainable 

for the long run.

 

35DOE, Energy Demands on Water Resources: Report to Congress on the 

Interdependency of Energy and Water (December 2006).

36In many states, public utility commissions are responsible for approving the rates (or 

prices) electric utilities charge their customers and ensuring they are reasonable. As part 

of approving rates, these commissions approve utility investments and, as a result, may 

consider whether specific technologies are reasonable.
 

Page 21 GAO-12-880 Energy-Water Nexus 

directive, DOE, Interior, and EPA signed a memorandum in April 2012 

describing their plans for multiagency collaboration on unconventional 

oil and gas research. According to the specialists we spoke with, 

direction from the White House is what led to action on the part of the 

agencies and the signing of the memorandum, and they believe a 

similar high-level push would be needed to spur meaningful 

collaborative action to address other energy-water nexus issues.

Recognizing the need for better coordination, Congress and some federal 

agencies have taken or are beginning to take some steps on energywater nexus issues, but many of these actions are either in their early 

stages or incomplete, as the following examples illustrate:

• With the Energy Policy Act of 2005, Congress directed the Secretary 

of Energy, through DOE’s Office of Science,37 to carry out a number 

of programs related to a wide variety of energy sciences. In particular, 

the act directs the Secretary to carry out a program to address the 

energy-water nexus and assess the effectiveness of existing 

programs at DOE and other federal agencies to address the nexus.38

 

37The Office of Science is the lead federal agency supporting fundamental scientific 

research for energy and the nation’s largest supporter of basic research in the physical 

sciences.

The provision also directs the Secretary to consult with the 

Administrator of EPA, the Secretary of the Interior, the Chief Engineer 

of the Army Corps of Engineers, the Secretary of Commerce, the 

Secretary of Defense, and other federal agencies as appropriate, to 

carry out the provision. DOE officials told us, however, that to date 

they have neither received nor requested any funding specifically 

designated to carry out the provision, nor has the agency requested 

funds for this purpose for fiscal year 2013. Furthermore, according to 

DOE officials, the Office of Science is not the appropriate office within 

DOE to carry out the program because the office conducts research 

38Energy Policy Act of 2005, Pub. L. No. 109-58, §§ 971, 979, 119 Stat. 594, 905 (codified 

at 42 U.S.C. §§ 16311, 16319 (2006)). Specifically, the act directs the Secretary to carry 

out a program of research, development, demonstration, and commercial application to (1) 

address energy-related issues associated with the provision of adequate water supplies, 

optimal management, and efficient use of water; (2) address water-related issues 

associated with the provision of adequate supplies, optimal management, and efficient 

use of energy; and (3) assess the effectiveness of existing programs within the 

department and other federal agencies to address these energy and water related issues. 

The program is to include, among other things, planning, analysis, and modeling of energy 

and water supply and demand.
 

Page 22 GAO-12-880 Energy-Water Nexus 

on the fundamentals of science. Instead, officials stated that the Office 

of the Under Secretary, which oversees work in areas such as energy 

efficiency and renewable and fossil energy, would be the more 

appropriate office to conduct such research.39

• Congress is also considering pending legislation related to energy and 

water that calls for enhanced collaborative efforts. A House bill, the 

Energy and Water Research Integration Act of 2012, would direct the 

Secretary of Energy to (1) integrate water considerations into energy 

research, development, and demonstration (RD&D) programs and 

projects; (2) develop a strategic plan identifying RD&D needs for 

those programs and projects; (3) collaborate with other federal 

agencies, within DOE, and with nongovernmental entities in 

developing the plan; and (4) develop an Energy-Water Architecture 

Council consisting of federal agencies and nongovernmental entities 

to promote data collection, reporting, and technology innovation.

Regardless of which 

office is best suited for this activity, by not carrying out this provision, 

we believe that DOE is missing an important opportunity to provide 

information that could possibly help fill some of the research and data 

gaps we and others have identified.

40

Another House bill, the Coordinating Water Research for a Clean 

Water Future Act of 2012, would, among other things, direct the 

President to begin implementation of a National Water and Research 

Development Initiative to, among other things, conduct research on 

how to ensure the systematic and coordinated collection of publicly 

available data on regional and national water resources and provide 

for interagency coordination of federal water research and 

development.41

• Some federal agencies have recognized the importance of 

collaboration on the energy-water nexus and have acted accordingly. 

For example, in April 2012, EPA proposed six principles to foster 

collaboration in the water and energy sectors to meet water and 

energy needs nationally and locally. One of the principles called for 

key stakeholders—governments, utilities, manufacturers, and 

consumers—in both sectors to move toward integrated energy and 

 

39The Office of Science may be able to enter into inter- and intra-agency agreements, 

under authorities like the Economy Act, with other federal offices to assist in carrying out 

the provision to the extent those offices are able to provide relevant assistance. See 31 

U.S.C. § 1535 (2006).

40H.R. 5827, 112th Cong. (2012).

41H.R. 5826, 112th Cong. (2012).
 

Page 23 GAO-12-880 Energy-Water Nexus 

water management from source, production, and generation, to the 

end user. Actions to support the principle include breaking down 

institutional barriers, improving transparency, and maximizing 

efficiencies; encouraging government agencies to look across 

missions; and developing partnerships between government and 

service providers.

• DOE, led by Sandia National Laboratories, held a series of workshops 

on energy and water issues in 2005 and 2006, according to DOE’s 

2006 report to Congress. The effort, known as the Energy-Water 

Roadmap process, included representatives from a broad range of 

groups, including environmental organizations; policy and regulatory 

groups; industry associations; and federal, state, and tribal 

government agencies. It was intended to help DOE and the United 

States assess current energy and water issues and concerns and 

identify appropriate interactions and coordination approaches. As part 

of this effort, participants at the workshops identified (1) gaps between 

current federal and state energy and water research and management 

programs and (2) major science and technology research and 

development steps necessary to address the challenges and gaps. 

According to the website for the Sandia National Laboratories, the 

Energy-Water Roadmap process was expected to result in a report 

summarizing needs; prioritization criteria; major gaps; innovative 

technical approaches and associated research needs; research and 

development priorities and strategies; and associated policy, 

regulatory, and economic assessments. However, as of September 

2012, no report has been issued.

Uncertainties—including the future makeup of the nation’s energy 

portfolio and the potential impacts of climate change—must be 

considered when developing and implementing national energy and water 

policies, according to our past work on the energy-water nexus, studies 

we reviewed, and specialists we spoke with. As the following examples 

demonstrate, these uncertainties could significantly affect the future 

supply and demand of both energy and water, and therefore are external 

factors that must be accounted for when developing national policies:

• The magnitude of the impacts on water resources stemming from the 

nation’s future energy use will vary depending on what sources of 

energy are pursued. For example, developing unconventional energy 

Uncertainties that Affect 

Energy and Water Must Be 

Considered in Setting 

Federal Policies Related to 

These Resources
 

Page 24 GAO-12-880 Energy-Water Nexus 

sources, such as shale oil and shale gas,42 could have significant 

impacts on the quality and quantity of water resources, but the 

magnitude of these impacts is unknown because of uncertainty about 

the future scale and scope of shale oil and gas development. 

Similarly, if oil shale becomes economically feasible to produce on a 

commercial scale, the industry could have significant impacts on 

water quality and quantity, but the magnitude of these impacts is 

unknown because of technological uncertainties and because the size 

of a future oil shale industry is unknown, as we discussed in our 

October 2010 report on oil shale.43 In addition, a recent report from 

DOE’s National Renewable Energy Laboratory looked at a variety of 

scenarios for the increased use of renewable energy sources to 

generate electricity. For example, the laboratory reported that if the 

country were able to switch to 80 percent renewable electricity by the 

year 2050, such a switch could reduce the power sector’s annual 

water use by approximately 50 percent.44 However, renewable energy 

sources also vary in their water use, so the type of renewable energy 

we use in the future will have varying impacts on water supplies. For 

example, solar photovoltaic panels and wind turbines consume 

minimal water during normal operation.45

 

42Shale oil and shale gas refers to product that is trapped within underground shale 

formations; these fine-grain sedimentary rocks can be rich sources of oil and natural gas. 

Unlike oil shale, shale oil and shale gas do not require heating for resource extraction.

However, concentrating 

solar power plants that use wet cooling could significantly increase 

water demand, consuming up to twice as much water per unit of 

43GAO-11-35. 

44The report looked at a variety of scenarios, ranging from 30- to 90-percent renewable 

generation in 2050. The report focused on 80-percent renewable generation because the 

laboratory’s analyses concluded that renewable energy generation from technologies that 

are commercially available today, in combination with a more flexible electric system, 

would be technically adequate to supply 80 percent of projected U.S. electricity generation 

in 2050, albeit at increased electricity prices compared with today’s baseline. Nearly 50 

percent of the renewable electricity in this 80-percent scenario consists of variable wind 

and solar photovoltaic generation. (National Renewable Energy Laboratory, Renewable 

Electricity Futures Study: Exploration of High-Penetration Renewable Electricity Futures, 

vol. 1 (2012).)

45Solar photovoltaic panels and wind turbines use small amounts of water for panel and 

blade washing, respectively.
 

Page 25 GAO-12-880 Energy-Water Nexus 

electricity produced as traditional fossil fuel power plants.46 Concerns 

with concentrating solar power plants are particularly acute in the 

Southwest—a prime location for siting these facilities because of 

abundant sunshine—because water supplies in the region are already 

limited.47

• As we previously discussed in our March 2011 report on energy for 

water supply,

Consequently, not fully understanding and accounting for 

the potential differences in the future energy portfolio’s impact on 

water supply and quality when developing a national energy policy 

may result in negative unintended consequences.

48 to address growing concerns about emerging 

contaminants and nutrients in the nation’s water bodies, additional or 

more stringent regulatory standards could increase the energy 

demands of treatment processes in the future, but the degree to which 

energy use would increase depends on the regulations that are 

implemented. Specifically, promulgation of more stringent standards 

would most likely require additional levels of treatment, and the use of 

more energy-intensive technologies, such as ozonation and 

membrane filtration,

49 may be necessary to meet such new 

standards.50

 

46Concentrating solar power plants operate by using mirrors to reflect and concentrate 

sunlight onto receivers that collect the solar energy and convert it to heat. This thermal 

energy is used to produce electricity via a steam turbine or heat engine driving a generator 

to produce electricity.

Regulatory changes could also increase energy 

demands at other stages of the urban water life cycle. For example, 

higher standards for effluent discharge from wastewater treatment 

plants could increase the energy required for treatment of the effluent. 

Furthermore, stricter water quality standards for receiving waters 

47According to DOE officials, concentrating solar power plants are generally being built 

with dry cooling systems in the Southwest to minimize water use. However, according to a 

2009 DOE report to Congress, while dry cooling can eliminate over 90 percent of the 

water consumed by wet-cooled concentrating solar power plants, wet cooling is preferred 

to minimize cost and maximize efficiency. 

48GAO-11-225. 

49Ozonation is a water treatment process that destroys bacteria and other microorganisms 

through the infusion of ozone, a gas produced by subjecting oxygen molecules to high 

electrical voltage. Membrane filtration uses pressure to force untreated water through a 

semipermeable membrane, thereby filtering out bacteria and other microorganisms, 

particulate material, and natural organic matter.

50Such standards may include drinking water standards set under the Safe Drinking Water 

Act or standards for the treatment of wastewater discharged from municipal wastewater 

treatment plants under the Clean Water Act. 
 

Page 26 GAO-12-880 Energy-Water Nexus 

could necessitate that more plants employ advanced treatment 

standards, resulting in increased energy use for the additional 

treatment or to pump effluent farther away to other waters. As a result, 

policymakers will need to consider the energy inputs that will be 

required to meet new water quality standards when developing these 

regulatory choices.

According to the literature we reviewed and specialists we spoke with, 

climate change, population growth, increased competition for resources, 

and demographic shifts are expected to exacerbate the challenges 

associated with water and energy supply and demand, and shifts in any 

of these areas are expected to increase demand for both of these 

resources. Moreover, the effects of climate change are expected to vary 

by location and, in some locations, are expected to increase demand for 

both energy and water resources while simultaneously decreasing water 

supplies. According to the literature we reviewed, higher temperatures 

from climate change are expected to lead to additional demand for air 

conditioning and, therefore, electricity. This increased electricity demand 

will, in turn, lead to increases in water consumption associated with power 

generation. However, at the same time, climate change is expected to 

change the quantity and reliability of water supplies so that less water 

may be available in some regions, thereby resulting in reduced water 

supplies for use by the energy sector, according to some specialists we 

spoke with. In addition, as one specialist told us, higher temperatures 

from climate change will produce more evaporation from water reservoirs 

and other bodies of water, such as the Great Lakes, which can produce 

significant water losses. Furthermore, the literature we reviewed and 

specialists we spoke with noted that the impacts of climate change are 

uncertain with some areas receiving more precipitation than they currently 

experience, rather than drought. 

Problems associated with climate change are only exacerbated by 

population growth and competition for water resources. Specifically, more 

people will consume more water, increasing the municipal sector’s water 

demand. To meet these increasing demands, some states, especially 

those in areas that are already water stressed, such as Texas, have 

pursued alternative sources of water, such as desalinated water, which 

are more energy-intensive than traditional groundwater and surface water 

supplies. In addition, because of a warmer climate and decreased 

precipitation, farmers are expected to withdraw more water to irrigate 

crops. Minimum water levels are also necessary for other uses, such as 

recreation and industry, as well as to support wildlife and maintain 

ecosystems. Furthermore, demographic shifts, such as migration to the 
 

Page 27 GAO-12-880 Energy-Water Nexus 

hot, arid Southwest, could place additional demands on both energy and 

water supplies. In light of all of these uncertainties, some specialists told 

us that water and energy policies must be resilient and flexible enough to 

adapt to changing circumstances. For example, these specialists told us 

that because of the uncertain effects of climate change, the development 

of plans and policies should be adaptable to account for variability over 

time and by location.

The growth in water and energy demands for development and other 

uses is occurring at a time when the nation’s supplies are stressed by a 

growing population, a variety of new and changing uses, and 

environmental challenges such as climate change. A number of agencies 

have responsibility for managing specific aspects of the energy-water 

nexus, including DOE, EPA, USDA, and Interior, but these agencies do 

not consistently or strategically collaborate on these inextricably linked 

issues to ensure a harmonized approach to energy and water resource 

planning. This lack of coordination often results in a stove-piped approach 

to managing these resources that does not take into account all the 

possible tradeoffs and interrelationships. Some agencies have taken 

steps to examine this issue within their own agency, such as DOE and 

Interior’s jointly organized meetings to improve thermoelectric power plant 

data in response to a recommendation from our October 2009 report. 

However, in general, federal efforts remain uncoordinated. Moreover, 

there is a need for enhanced research and data efforts that could benefit 

from greater interagency cooperation. The Energy Policy Act of 2005 

requires DOE to implement a program of research, development, 

demonstration, and commercial action to address energy and water 

issues and assess existing federal programs, but DOE has not yet 

implemented this program. In not carrying out this directive, DOE is 

missing an opportunity to provide information that could help Congress, 

other federal agencies, and the public better understand the key energywater nexus issues identified in our series of reports and take coordinated 

action to protect these invaluable resources.

To help address some of the research and data gaps that we and others 

have identified related to the tradeoffs associated with the energy and 

water nexus, and to ensure collaboration to address the nexus, we 

recommend that the Secretary of Energy take the actions necessary to 

establish a program to address the energy-water nexus, with involvement 

from other federal agencies as described in the Energy Policy Act of 

2005.

Conclusions

Recommendation for 

Executive Action
 

Page 28 GAO-12-880 Energy-Water Nexus 

We provided a draft of this report to USDA, DOE, Interior, and EPA for 

review and comment. In its written comments, reproduced in appendix II, 

DOE agreed with our recommendation. Specifically, DOE stated that it 

already has a number of research activities underway related to the 

energy-water nexus, such as energy-water data collection and modeling. 

In addition, DOE stated that it will initiate more assertive engagement with 

program managers through an internal workshop to discuss existing 

activities and clarify priority areas for further data collection and analysis. 

As part of its efforts, DOE stated that it will continue to engage other 

agencies and collaborate with experts. 

EPA provided technical comments, which we incorporated as appropriate. 

In its technical comments, EPA stated that the agency supported the 

findings of the report, but noted that more emphasis should be placed on 

the changes in population demographics that stress the supply of energy 

and water. Specifically, the agency identified increasing population shifts 

to coastal areas, desalinization, increased use of air conditioning, and 

agricultural irrigation as stressors of particular concern. We agree that 

these areas could affect the energy-water nexus, as we discuss in our 

report. EPA also identified the need for a comprehensive systems 

analysis of energy, water, and agricultural cycles and their feedback loops

to help avoid unintended consequences. USDA and Interior did not 

provide any comments.

As agreed with your office, unless you publicly announce the contents of 

this report earlier, we plan no further distribution until 30 days from the 

report date. At that time, we will send copies to the Secretary of Energy, 

the appropriate congressional committees, and other interested parties. In 

addition, the report will be available at no charge on the GAO website at 

http://www.gao.gov. 

If you or your staff have any questions about this report, please contact 

Anu K. Mittal at (202) 512-6100 or mittala@gao.gov or Frank Rusco at 

(202) 512-3841 or ruscof@gao.gov. Contact points for our Offices of 

Congressional Relations and Public Affairs may be found on the last page 

Agency Comments 

and Our Evaluation
 

Page 29 GAO-12-880 Energy-Water Nexus 

of this report. GAO staff who made key contributions to this report are 

listed in appendix III. 

Sincerely yours,

Anu K. Mittal

Director, Natural Resources and Environment

Frank Rusco

Director, Natural Resources and Environment
Appendix I: Objectives, Scope, and 

Methodology

Page 30 GAO-12-880 Energy-Water Nexus 

To conduct this work, we systematically reviewed GAO’s five prior reports 

on the energy-water nexus to develop the key issues that Congress and 

federal agencies need to consider when developing and implementing 

national policies for energy and water resources. To validate these 

themes, we conducted a content analysis of 11 key studies and reports 

that examine this nexus, including peer-reviewed scientific periodicals, 

government-sponsored research and studies, and reports from 

nongovernmental research organizations. We also included in the content 

analysis 19 interviews with a wide range of 37 specialists whom we 

identified as having expertise related to the energy-water nexus in the 

United States. For the purposes of our interview analysis, each interview 

represents the views of one specialist even if more than one specialist 

was present at the interview. We selected these specialists using an 

iterative process, soliciting additional names from each person we 

interviewed. From among those identified, we conducted structured 

interviews with specialists who could provide us with a broad range of 

perspectives on the energy-water nexus as well as specialists whom we 

identified during our systematic review of studies who have analyzed (1) 

the energy-water nexus in general or (2) particular segments (i.e., water 

use by thermoelectric power plants) of the nexus. These specialists 

represented a variety of organizations, including federal officials; 

university researchers; water and energy industry representatives from 

groups such as the American Water Works Association and the Electric 

Power Research Institute; and nongovernmental organizations, such as 

the Pacific Institute.1

We conducted a content analysis on the key literature and interviews with 

specialists using NVivo software. Content analysis is a methodology for 

structuring and analyzing written material. Specifically, using our 

systematic review of GAO’s energy-water nexus reports to identify key 

issues that Congress and federal agencies need to consider when 

developing and implementing national policies for energy and water 

Representatives from federal agencies included 

officials, scientists, and researchers from the Department of Energy’s 

national laboratories and Energy Information Administration; the 

Environmental Protection Agency; the Department of the Interior’s U.S. 

Geological Survey; and the U.S. Department of Agriculture. We also 

reviewed federal laws and regulations as applicable.

 

1

The Pacific Institute conducts interdisciplinary research and partners with stakeholders to 

produce solutions that advance environmental protection, economic development, and 

social equity in California, nationally, and internationally.

Appendix I: Objectives, Scope, and 

Methodology 
Appendix I: Objectives, Scope, and 

Methodology

Page 31 GAO-12-880 Energy-Water Nexus 

resources, we reviewed each study and interview and coded statements 

within them based on themes we developed from the GAO reports. The 

coding was conducted independently by two GAO analysts after checking 

for intercoder reliability. We developed agreement statistics and 

discussed and resolved any discrepancies in coding. We used the 

following categories to quantify the literature and responses of specialists: 

“some” refers to at least two studies or specialists, “several” refers to at 

least five studies or specialists, and “many” refers to eight or more studies 

or specialists.

We conducted this performance audit from March 2012 to September 

2012, in accordance with generally accepted government auditing 

standards. Those standards require that we plan and perform the audit to 

obtain sufficient, appropriate evidence to provide a reasonable basis for 

our findings and conclusions based on our audit objectives. We believe 

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.
Appendix II: Comments from the Department 

of Energy

Page 32 GAO-12-880 Energy-Water Nexus 

Appendix II: Comments from the Department 

of Energy
Appendix II: Comments from the Department 

of Energy

Page 33 GAO-12-880 Energy-Water Nexus 
Appendix III: GAO Contacts and Staff 

Acknowledgments

Page 34 GAO-12-880 Energy-Water Nexus 

Anu K. Mittal, (202) 512-6100 or mittala@gao.gov

Frank Rusco, (202) 512-3841 or ruscof@gao.gov

In addition to the contacts named above, Elizabeth Erdmann (Assistant 

Director), Antoinette Capaccio, Janice Ceperich, Alison O’Neill, Steven 

Putansu, Rebecca Shea, and Lisa Vojta made key contributions to this 

report.

Appendix III: GAO Contacts and Staff 

Acknowledgments 

GAO Contacts 

Staff 

Acknowledgments

(361388)
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