Energy-Water Nexus:
The Water Sector’s Energy Use
Claudia Copeland
Specialist in Resources and Environmental Policy
January 3, 2014
Congressional Research Service
7-5700
www.crs.gov
R43200
Energy-Water Nexus: The Water Sector’s Energy Use
Summary
Water and energy are resources that are reciprocally and mutually linked, because meeting energy
needs requires water, often in large quantities, for mining, fuel production, hydropower, and
power plant cooling, and energy is needed for pumping, treatment, and distribution of water and
for collection, treatment, and discharge of wastewater. This interrelationship is often referred to as
the energy-water nexus, or the water-energy nexus. There is growing recognition that “saving
water saves energy.” Energy efficiency initiatives offer opportunities for delivering significant
water savings, and likewise, water efficiency initiatives offer opportunities for delivering
significant energy savings. In addition, saving water also reduces carbon emissions by saving
energy otherwise generated to move and treat water.
This report provides background on energy for facilities that treat and deliver water to end users
and also dispose of and discharge wastewater. Energy use for water is a function of many
variables, including water source (surface water pumping typically requires less energy than
groundwater pumping), treatment (high ambient quality raw water requires less treatment than
brackish or seawater), intended end-use, distribution (water pumped long distances requires more
energy), amount of water loss in the system through leakage and evaporation, and level of
wastewater treatment (stringency of water quality regulations to meet discharge standards).
Likewise, the intensity of energy use of water, which is the relative amount of energy needed for a
task such as pumping water, varies depending on characteristics such as topography (affecting
groundwater recharge), climate, seasonal temperature, and rainfall. Most of the energy used for
water-related purposes is in the form of electricity. Estimates of water-related energy use range
from 4% to perhaps 13% of the nation’s electricity generation, but regional differences can be
significant. In California, for example, as much as 19% of the state’s electricity consumption is
for pumping, treating, collecting and discharging water and wastewater.
Energy consumption by public drinking water and wastewater utilities, which are primarily
owned and operated by local governments, can represent 30-40% of a municipality’s energy bill.
At drinking water plants, the largest energy use (about 80%) is to operate motors for pumping. At
wastewater treatment plants, aeration, pumping, and solids processing account for most of the
electricity that is used. Energy is the second highest budget item for these utilities, after labor
costs, so energy conservation and efficiency are issues of increasing importance to many of them.
Opportunities for efficiency exist in several categories, such as upgrading to more efficient
equipment, improving energy management, and generating energy on-site to offset purchased
electricity. However, barriers to improved energy efficiency by water and wastewater utilities
exist, including capital costs and reluctance by utility officials to change practices or implement
new technologies.
Topics for research to better understand water-related energy use include studies of energy
demands for water at local, regional, and national scales; development of consistent data
collection methodology to track water and energy data across all sectors; development and
implementation of advanced technologies that save energy and water; and analysis of incentives,
disincentives, and lack of incentives to investing in cost-effective energy or water efficiency
measures.
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Energy-Water Nexus: The Water Sector’s Energy Use
Contents
Energy for Water Use ................................................................................................................ 2
Energy for Water Supply and Wastewater Facilities.................................................................. 5
Research and Information Needs ............................................................................................... 9
Figures
Figure 1. Examples of Interrelationships Between Water and Energy ............................................ 1
Contacts
Author Contact Information........................................................................................................... 10
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Energy-Water Nexus: The Water Sector’s Energy Use
ater and energy are critical resources that are reciprocally and mutually linked.
Meeting energy needs depends upon the availability of water, often in large quantities,
Wfor mineral extraction and mining, fuel production, hydropower, and thermoelectric
power plant cooling.1 Likewise, energy is required for the pumping, conveyance, treatment and
conditioning, and distribution of water and for collection, treatment, and discharge of wastewater.
This interdependence, which is often described as the water-energy nexus, or energy-water nexus,
is illustrated in the following graphic from a U.S. Department of Energy report.
Figure 1. Examples of Interrelationships Between Water and Energy
Source: U.S. Department of Energy, Energy Demands on Water Resources, Report to Congress on the
Interdependency of Energy and Water, December 2006, p. 13.
This report first discusses water-related energy use broadly and then energy for facilities that treat
and deliver water to end users and also dispose of and discharge wastewater. There is growing
recognition that “saving energy saves water,” and the report describes options and impediments
for energy efficiency by these facilities. It also identifies several areas of research and information
needs concerning energy for water uses.
1 CRS Report R43199, Energy-Water Nexus: The Energy Sector’s Water Use, discusses the related topic of water needs
for the energy sector.
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Energy-Water Nexus: The Water Sector’s Energy Use
Energy for Water Use
In the United States, more than 400 billion gallons of water is withdrawn daily from surface and
ground water sources of freshwater and saline-water to supply domestic uses, agriculture
including irrigation, industry, mining, and thermoelectric power.2 Information about the energy—
especially electricity—that is needed to pump, transport, deliver, and process that water is
fragmentary and not well documented overall. In particular, as described further below, energy
needs for self-supplied domestic, industrial, and energy water is largely unknown, but are likely
to be large. Interest has been growing in better understanding of the energy-related needs of
providing water to diverse sectors of the economy.
In a 2002 report, the Electric Power Research Institute (EPRI) estimated that 4% of the nation’s
electricity use goes towards moving and treating water and wastewater by public and private
entities.3 Today that estimate is considered a good starting place for understanding the magnitude
of energy demands for providing these water services, but deficient in several respects.
• It relied on secondary source data that were then well over a decade old.
• It did not include future projections of electricity requirements for water supplies
in the thermoelectric sector (because it assumed that energy for water use in this
sector would decline).
• It did not consider on-site heating, cooling, pumping and softening of water for
end-use.
• It did not consider that in the future a large proportion of new water demands will
be met by sources with greater energy intensities, such as groundwater pumped
from greater depths and seawater desalination.
More recently, others have attempted to expand on the EPRI analysis, using additional and
updated data from a variety of sources, to develop a baseline estimate of water-related energy use
in the United States. These analyses suggest that energy for publicly supplied water and
wastewater is a larger share of U.S. energy use than EPRI estimated. For example, a 2009 report
by the River Network, a national advocacy group for freshwater conservation and watershed
restoration, estimated that water-related energy use, including for heating in the residential and
commercial sectors, was 52.1 billion killowatt hours (kWh), equivalent to 13% of U.S. electricity
consumption in 2007.4 National data can obscure differences in water-related energy use that are
regional or state-specific, as reflected in a 2005 study by the California Energy Commission,
which found that “water-related energy use [in California] consumes 19 percent of the state’s
electricity, 30 percent of its natural gas, and 88 billion gallons of diesel fuel every year – and this
demand is growing.” Pumps that move water from the San Joaquin Valley to southern California
for domestic and irrigation water uses are the single largest power load in the state.5
2 Susan S. Hutson, Nancy L. Barber, and Joan F. Kenny, et al., Estimated Use of Water in the United States in 2000,
U.S. Department of the Interior, U.S. Geological Survey, U.S. Geological Survey Circular 1268, 2004.
3 Electric Power Research Institute, Water & Sustainability (Volume 4): U.S. Electricity Consumption for Water Supply
& Treatment—the Next Half Century, 1006787, Topical Report, March 2002.
4 Bevan Griffiths-Sattenspiel and Wendy Wilson, The Carbon Footprint of Water, River Network, May 2009.
Hereinafter, The Carbon Footprint of Water.
5 California Energy Commission, California’s Water-Energy Relationship, Final Staff Report, CEC-700-2005-011-SF,
November 2005, p. 1. Hereinafter, California’s Water-Energy Relationship.
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Energy-Water Nexus: The Water Sector’s Energy Use
Researchers at the University of Texas at Austin have attempted to quantify the energy embedded
in the U.S. public water supply, which is the primary water source of residential, commercial, and
municipal users. One such analysis concluded that energy use associated with the public water
supply is 4.1% of the nation’s annual primary energy consumption and 6.1% of national
electricity consumption, but this analysis excluded energy requirements associated with water for
agriculture, industrial, and self-supplied sectors (e.g., agriculture, thermoelectric, and mining). In
this analysis, electricity consumption by public drinking water and wastewater utilities for
pumping, conveyance, treatment, distribution, and discharge was 56.6 billion kWh, or 11.5% of
primary energy and 21.6% of electricity consumption for water end-use, respectively, in 2009.6
A second analysis by these researchers looked more broadly at energy needs for water supply,
adding industrial and thermoelectric sectors to others considered previously.7 Water-related
energy use throughout the economy varies across sectors, and analysis of some sectors is complex
and limited by incomplete data (e.g., cooking-related activities vary across residences and are not
well documented). This analysis concluded that direct water-related energy consumption was
12.6% of national primary energy consumption in 2010. This amount of energy, 12.3 quadrillion
BTUs, is the equivalent of annual energy consumption of about 40 million Americans. It also
estimated that energy losses at the point of electricity generation, transmission and distribution,
and end-use represent 58% of the total primary energy that was consumed for water-related
purposes, reflecting varying efficiencies of water heating and boiler technologies. The estimate of
waste heat losses is subject to uncertainty, the researchers said.
Because of inadequate data and other factors, missing from some analyses is water-related energy
for several important end-use sectors.
• Self-supplied water, which is a high percentage of power plant use and of some
industrial uses such as mining. Some of this energy-for-water is in the form of
electricity, but much of it is likely direct use of fuels on-site. Privately operated
residential water supply wells also utilize energy for pumping, none of which is
accounted for.
• Agricultural use of water for livestock and irrigation—second in volume only to
water use for thermoelectric power, according to the U.S. Geological Survey—is
generally omitted from these analyses, although substantial energy, which
generally is self-supplied, is needed for pumping.
• The transportation sector, although the majority of energy consumed is for
petroleum-based transportation fuels, which is presumably reflected in water-for-
energy analyses.
• The bottled water industry, which is a substantial drinking water source in the
United States and consumes energy to collect, treat, bottle, and distribute its
products.
6 Kelly M. Twomey and Michael E. Webber, “Evaluating the Energy Intensity of the US Public Water Supply,”
Proceedings of the ASME 2011 5th International Conference on Energy Sustainability, ES2011-54165, August 2011.
Hereinafter, Twomey and Webber 2011.
7 Kelly T. Sanders and Michael E. Webber, “Evaluating the energy consumed for water use in the United States,”
Environmental Research Letters, vol. 7, 034034 (2012).
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Energy-Water Nexus: The Water Sector’s Energy Use
Energy use for water is a function of many variables, including water source (surface water
pumping typically requires less energy than groundwater pumping), treatment (high ambient
quality raw water requires less treatment than brackish or seawater), intended end-use,
distribution (water pumped long distances requires more energy), amount of water loss in the
system through leakage and evaporation, and level of wastewater treatment (stringency of water
quality regulations to meet discharge standards). Likewise, the intensity of energy use of water8
varies depending on characteristics such as topography (affecting groundwater recharge), climate,
seasonal temperature, and rainfall. Focusing on national data can mask large variations, because
the United States is a difficult country to generalize. For example, the lifecycle energy-intensity
of water in cities nationally is estimated to be 3,300-3,600 kWh per million gallons delivered and
treated, but ranges from 2,700 kWh/million gallons in New York, New York, to 5,000 kWh per
million gallons in Austin, Texas.9 Energy intensity varies within states, as well. In California, the
energy intensity of the water use cycle ranges from 4,000 kWh per million gallons in the northern
part of the state to 12,700 kWh per million gallons in southern California, reflecting differences
in the volume of water pumped, lifted, and transported hundreds of miles and over mountains
from points of collection to points of need in the southern part of the state.10 The energy intensity
of a particular activity’s water use, also described as the embedded energy of the activity, can
have disproportionate impacts elsewhere. For example, policies that promote the use of energy-
intensive water supply such as pumping and distributing water over long distances, rather than
policies that promote water conservation, water reuse, or aquifer recharge, adversely impact one
sector to serve another.11
In every sector, there are opportunities for practices that would save energy and also save water.
The Environmental Protection Agency’s (EPA) WaterSense program promotes this concept by
emphasizing that “saving water saves energy.”12 Energy efficiency initiatives offer opportunities
for delivering significant water savings, and likewise, water efficiency initiatives offer
opportunities for delivering significant energy savings. In the commercial, industrial, and
institutional sectors, potential water savings through energy efficiency and other measures could
be 15-30% without reducing the services derived from the water. The potential for significant
water and energy savings also exists in other sectors such as agriculture.13
8 Energy intensity is the relative amount of energy needed to perform water management-related tasks such as treating
and pumping water. It is typically expressed as the number of kilowatt-hours per million gallons of water.
9 Twomey and Webber 2011, p. 8.
10 California’s Energy-Water Relationship, pp. 9-11.
11 Carey W. King, Ashlynn S. Stillwell, and Kelly M. Twomey, et al., “Coherence Between Water and Energy
Policies,” Natural Resources Journal, vol. 53, no. 1 (Spring 2013), p. 185.Hereinafter, King, Stillwell, and Twomey
2013.
12 The WaterSense program offers a label for products and services that are certified to save water without sacrificing
performance, thus promoting water efficiency and supporting a market for water-efficient products. WaterSense
addresses residential and commercial water use. According to EPA, since the program’s inception in 2006, WaterSense
has helped consumers save a cumulative 487 billion gallons of water and $8.9 billion in water and energy bills. In
addition, the Department of Energy has established minimum energy conservation standards for more than 50
categories of residential, commercial, and industrial appliances and equipment, including standards for several
categories of appliances and devices that also specify maximum water use standards (showerheads and faucets; toilets
and urinals; residential and commercial clothes washers; residential dishwashers; and prerinse spray valves). These
standards were promulgated under the Energy Policy and Conservation Act of 1975, as amended.
13 See Alliance for Water Efficiency, http://www.allianceforwaterefficiency.org/; the American Council for an Energy-
Efficient Economy, http://www.acee.org; and The Carbon Footprint of Water, pp. 26-29.
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Energy-Water Nexus: The Water Sector’s Energy Use
Generating the energy associated with water use also produces carbon dioxide (CO2) emissions
that contribute to climate change. It has been estimated that water-related carbon emissions in
2005 were approximately 290 million metric tons, or 5% of all U.S. carbon emissions. Water-
related CO2 emissions were equivalent to the annual greenhouse gas emissions of 53 million
passenger vehicles. By sector, water heating was responsible for 70% of the water-related carbon
emissions, wastewater treatment was responsible for 18%, water supply was responsible for 8%,
and agricultural activities were responsible for 6%.14 Thus, saving water saves energy and also
reduces carbon emissions.15
Energy for Water Supply and Wastewater Facilities
There are about 200,000 drinking water treatment systems in the country, of which about 52,000
are community water systems that serve 25 or more year-round residents. Most U.S. drinking
water is provided by relatively large community water systems. Nearly 85% of the U.S.
population is supplied by about 5% of these systems; the remaining 95% include a large number
of small and very small systems serving 3,300 persons or fewer. Public agencies own and operate
most community water systems; a small number are privately operated. Smaller utilities use more
electricity and pay more per unit of water produced than do medium and large utilities, due to
economies of scale. Nearly all of the energy consumed is electricity, about 80% of which is used
by motors for pumping.
There are approximately 15,000 U.S. wastewater treatment plants. Most are publicly owned, and
they serve more than 75% of the U.S. population. Nearly 70% of facilities are small, serving only
10% of the U.S. population. Approximately 22% are large (with flow greater than 1 million
gallons per day) and serve over 85% of the population. Wastewater systems generally consist of
collection systems (sewers and pumping stations), treatment facilities, and effluent disposal. Like
water supply utilities, nearly all of the energy consumed is electricity. Wastewater aeration,
pumping, and solids processing account for most of the electricity used in wastewater treatment.
For both types of systems, greater amounts of energy are required for more advanced treatment
levels. Similarly, the age of the system and equipment are important: as systems age, equipment
decreases in efficiency, resulting in an increase in electricity requirements.
According to EPA, community drinking water and publicly owned wastewater systems use 75
billion kWh per year—as much as the pulp and paper and petroleum industries combined, or
enough electricity to power 6.75 million homes.16 Energy is the second highest budget item for
municipal drinking water and wastewater facilities, after labor costs, with utilities spending about
14 The Carbon Footprint of Water, p. 24. In this analysis, carbon emissions resulting from water supply and treatment
assumed that all energy comes from electricity, with a carbon intensity of 1.36 lbs. CO2 /kWh. The carbon intensity of
other energy sources varies, ranging from 0.12 lbs. CO2 per cubic foot of natural gas to 22.4 lbs. CO2 per gallon of fuel
oil.
15 See, for example, United Utilities, “Water and your carbon footprint,” http://www.unitedutilities.com/water-and-
your-carbon-footprint.aspx; and Wisconsin Department of Natural Resources, “Save Energy and Reduce Carbon
Emissions,” http://dnr.wi.gov/org/caer/ce/eek/teacher/globaltip.htm.
16 Cheryl McGovern, U.S. Environmental Protection Agency, “Benchmarking Wastewater Facilities in Portfolio
Manager,” June 23, 2009, http://www.epa.gov/region9/waterinfrastructure/training/energy-workshop/docs/2009/
energystar-benchmark.pdf.
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$4 billion a year. Energy consumption by drinking water and wastewater utilities can comprise
30-40% of a municipality’s total energy bill.
Water utilities are highly regulated entities whose primary goals are to meet regulatory
requirements for protecting public health and the environment and to provide services for
reasonable and fair rates. The energy efficiency of these utilities generally has not been a primary
goal or considered as an element of rate determinations. Nevertheless, as populations grow and
environmental requirements become more stringent, demand for electricity at drinking water and
wastewater utility plants is expected to grow by approximately 20%. Moreover, as electricity
rates increase, energy conservation and efficiency are issues of increasing importance to many
utilities. By some estimates, potential energy savings by drinking water and wastewater utilities
are in the range of 15-30% per year.17 Opportunities for efficiency exist in several categories.
• Optimizing system processes, such as modifying pumping and aeration
operations and implementing monitoring and control systems through SCADA
(supervisory control and data acquisition) systems to increase the energy
efficiency of equipment. EPRI has estimated that drinking water facilities can
achieve energy savings of 5-15% through adjustable speed drives and high-
efficiency motors and drives and 10-20% through process optimization and
SCADA systems. In wastewater facilities, EPRI estimates that 10-20% energy
savings are possible through process optimization.18
• Upgrading to more efficient equipment and right-sizing equipment for the
capacity of the facility (plants and pipes often are oversized, to accommodate
future peak load). Pumps and other equipment used beyond their expected life
operate well below optimal efficiency. In addition, energy is embedded through
pipe systems, since leaking drinking water pipes require more energy to deliver
water to the end user. Leaky sewer lines allow groundwater to infiltrate and
increase the flow of water into the wastewater treatment plant. All water systems
have losses, which are cumulative along segments of the water-use cycle.
Projects to address water loss and improve end-use efficiency can be promoted as
both water- and energy-savings investments.
• Improved energy management. It is widely recognized that water utilities need
to develop better understanding of their current energy use, and public and
private research and programs have focused on this goal. For example, some
states have developed programs to help water utilities better manage energy use.
The New York State Energy Research and Development Authority has done
extensive work to help water utilities benchmark their energy use and support a
range of initiatives through its Focus on Municipal Water and Wastewater
Treatment program. It developed a best practices handbook for the water and
wastewater sectors, including methods to track performance and assess program
effectiveness.19 The California Energy Commission also has been active on
energy management issues. It has reported on case studies of water facilities
17 Consortium for Energy Efficiency, CEE National Municipal Water and Wastewater Facility Initiative, January 1,
2010, p. 1.
18 Ibid., p. 8.
19 See http://www.nyserda.ny.gov/BusinessAreas/Energy-Efficiency-and-Renewable-Programs/Commercial-and-
Industrial/Sectors/Municipal-Water-and-Wastewater-Facilities.aspx.
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throughout the state that implemented energy efficiency measures, including
resulting energy and cost savings. In 2006, the California Public Utilities
Commission (CPUC) directed the state’s largest electric utilities to partner with
water agencies, undertake specific water conservation and efficiency programs,
and measure the results.20 Because one of the largest end uses of electricity in
California is in treating, heating, and conveying water, energy companies in that
state are working with the water sector to help utilities and companies reduce
their energy use and boost their efficiency. At the federal level, EPA has
developed a number of tools for water utilities, including an energy management
guidebook, energy conservation guides, and self-assessment and energy audit
tools. Energy Star, a joint program of the Department of Energy and EPA, has
developed a Portfolio Manager, an online benchmarking tool that allows drinking
water and wastewater utilities to evaluate their energy use and compare their
operations to similar facilities.21 Others have contributed research on best
practices, energy conservation, and benchmarking energy use, including the
Water Environment Research Foundation, the Water Research Foundation, and
the American Council for an Energy-Efficient Economy.
• Some water utilities are generating energy on-site to offset purchased
electricity. Beyond efficiency measures, they illustrate ways in which water
utilities are reducing their energy costs by recovering energy from municipal
waste and using the resulting biogas to generate electricity, heat the plant, and in
some cases sell electricity back to the grid. For example, D.C. Water, the
wastewater utility in Washington, D.C., is constructing a project to convert
residuals that remain after wastewater is treated into fuel for combined heat and
power operations at the facility. The utility estimates that when the project is
completed, it will save $10 million per year on electricity (powering one-third of
the treatment plant) and another $10 million annually in solid waste management.
Another example is the Gloversville-Johnstown, NY Joint Wastewater Treatment
Facilities. In 2003, it began accepting dairy whey as a fuel for its own energy
through a combined heat and power process. Reduced electrical costs save the
utility about $500,000 per year, and accepting the dairy wastes results in
additional revenue of $750,000 annually. Plants also are using other sources of
renewable energy: solar panels at the Calera Creek Water Recycling Plant in
Pacifica, California, provide 10-15% of the plant’s energy needs and save an
estimated $100,000 per year. Savings from such projects are contingent upon
recouping capital investment costs.
Several barriers to improved energy efficiency by water and wastewater utilities are apparent.
Many of them derive from the culture of water utilities and outside constraints placed on them.22
20 ECONorthwest, Embedded Energy in Water Pilot Programs Impact Evaluation, Final Report, Study
ID:CPU0053.01, March 9, 2011.
21 See http://water.epa.gov/infrastructure/sustain/waterefficiency.cfm. The Portfolio Manager can be used by a range of
facilities, including K-12 schools, hospitals, hotels, and offices, to track and assess energy and water consumption. It
was extended to wastewater utilities in 2007 and later to drinking water utilities.
22 See discussion in U.S. Government Accountability Office, 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, March 2011.
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• Cost. Utilities have limited resources. Their capital and operations budgets are
constrained, while the up-front costs of installing more energy-efficient
equipment can be prohibitive. Some funding sources to finance projects do exist
(e.g., private sector, municipal bonds), but may not be suitable or well known to
water utility officials. Federal and state funding for energy efficiency projects is
limited.
• Municipalities that own and operate water utilities generally are risk-averse,
reluctant to change practices, and hesitant to implement new technologies. The
tendency is to wait until equipment fails rather than be pro-active.
• Facility operators who could advocate for energy efficiency often are
disconnected from those in the utility who pay the electricity bill. Most water and
wastewater facilities were built decades ago when electricity costs were low
enough to be of little concern. Facilities and equipment were designed to run
continuously, without regard for wasted energy. To the extent that water utilities
can pass on energy costs to customers, there may be little incentive to investigate
energy efficiencies. Utility managers may not understand how energy is used at a
plant and how to reduce, or even control, energy costs.
Other barriers stem from a lack of coherence and coordination between water and energy policies,
planning, and decisionmaking roles. Energy and water decisions have historically been made
independently of each other. Water planners typically assume that they have the energy that they
need, and energy planners assume that they have the water that they need. Both are likely to use
different strategic planning: private companies acting under market forces dictate the location of
energy infrastructure, while water infrastructure is often located using public interest criteria. A
mismatch in planning objectives by different actors can prevent the beneficial siting and combing
of technologies. Likewise, water policy in the United States is usually structured in a bottom-up
fashion with decisions driven by local water authorities, because water supply management is
generally the responsibility of states. Energy policy, in contrast, is usually structured in a top-
down fashion with federal agencies setting many standards and requirements.23
To overcome such barriers, a 2013 report recommends that the electricity, water supply, and
wastewater sectors should foster cross-sector communication and engage in collaborative
planning. To reduce potential disincentives and risks of cross-sector coordination, the report
suggests that states could implement policies that incentivize wastewater plants to install energy
projects and give credits to electric utilities for incorporating those generation sources into their
portfolios. Although some states do this now (for example, Massachusetts), the report states that
new policies are needed to build the confidence of leaders in the water and electric power sectors
and motivate them to “go beyond compliance.”24
23 King, Stillwell, and Twomey 2013, pp. 185-191.
24 The Johnson Foundation at Wingspread, Building Resilient Utilities, How Water and Electric Utilities Can Co-
Create their Futures, November 2013, p. 15.
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Research and Information Needs
Several areas of research and information needs concerning energy for water uses have been
identified by a range of researchers and stakeholders.25 They suggest:
• Data that could help decision makers and users fill what is now an incomplete
picture of energy needs for water uses are lacking. This is apparent across sectors
and also within individual sectors. The U.S. Geological Survey collects water use
data, but national scale reports generally are issued only every five years,26 the
level of detail is limited, and related energy use is not considered. The
Department of Energy collects energy data and forecasts energy use, but its work
to address energy for water use is limited.27 No public or private entity
systematically collects energy data from public water utilities, users who self-
supply their water, or other end users of water. Data that exist are scattered and
often are not available at a scale needed by decision makers.
• More integrated research is needed on water and energy operations. Information
is needed to understand where energy is used in water and wastewater
infrastructure facilities, what opportunities for improvement exist, and how to
establish priorities for action. Ideally, consistent data collection methodology is
needed to gather and track water and energy data across all sectors and within
sectors, such as at the utility level, and to aid benchmarking. Standards for data
collection, coordination, and quality control are lacking.
• Research is needed on advanced technologies that save energy and save water,
and partnerships between government and the private sector that move research
and development from bench-scale to implementation are needed.
• Better understanding is needed of linkages between energy, water, land, and
agriculture and risks of climate change and extreme weather events on water
availability and energy supply.
• Policies and approaches are needed to encourage the water and energy sectors to
move toward integrated resource management.
• Analysis is needed of incentives, disincentives, and lack of incentives to
investing in cost-effective energy or water efficiency measures. One area of
interest is regulatory barriers to co-implementation of efficiency programs in the
water and energy sectors, such as policies in some states that restrict electric and
gas utilities from utilizing biogas that is recovered from wastewater utilities.
25 For discussion of research and information needs, see, for example, GEI Consultants, Water-Energy Nexus Research,
Recommendations for Future Opportunities, Alliance for Water Efficiency and American Council for an Energy-
Efficient Economy, Final Report, Project No. 130240, June 2013.
26 The most recent national report was issued in 2004 and describes estimated U.S. use of water in 2000.
27 DOE’s Energy Information Administration (EIA) has conducted periodic Commercial Buildings Energy
Consumption Surveys since the mid-1970s. A limited number of questions about water consumption were asked for the
first time in the 2007 survey, including total volume of water consumed, cost, whether the volume was metered or
estimated, and how much of the water was used outdoors. Sixteen commercial building categories (e.g., health care,
lodging, food service) were surveyed. EIA reported on the results, without analysis, in 2012. See http://www.eia.gov/
consumption/commercial/reports/2007/hospital-water-data-collection.cfm.
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• More education and outreach to all types of water users, the general public, and
public officials are needed on the water-energy nexus and how improving
efficiency involves the reciprocity of saving energy and saving water.
Author Contact Information
Claudia Copeland
Specialist in Resources and Environmental Policy
ccopeland@crs.loc.gov, 7-7227
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