Chapter 9. The Energy and Emissions Intensity of Urban Water
Supply Sources in two Southern California Water Districts
Introduction
Many of the ways in which water is provided to the Southern California region are
increasingly energy intensive, requiring large amounts of energy for transportation, treatment
and distribution. Crucial to the security and economy of the United States in general and
California in particular is the sustainable supply of both water and energy. In Southern
California, where water shortages are cyclical and where future efforts to import water will
require increasing amounts of energy, the water-energy nexus has particular significance.
Modeling the spatial relationship between water and energy sources, infrastructure and
consumers provides insight into the interdependence of water and energy systems. It is important
to note that while the full water-energy nexus encompasses embodied energy in consumed water
as well as energy consumed during use and the energy sector’s consumption of water, this study
examines only the portion of the water-energy nexus concerned with providing water to
consumers (i.e. the transport, treatment and distribution of potable water).
Due to substantial water imports, the energy intensity of water provisioning in Southern
California is among the highest in the country (U.S. Department of Energy 2006). The
Metropolitan Water District (MWD) estimates that the energy used to deliver water to residential
customers is equivalent to approximately one-third of total household electricity use in the region
(MWD 1999). As discussed in previous chapters, for example, the City of Los Angeles draws
water far from the site of consumption —major sources including the Los Angeles Aqueduct, the
Colorado River, and the Sacramento Delta —with each source subject to potentially critical
water shortages in the coming years. As these shortages become a reality, the Los Angeles
Department of Water and Power (LADWP) is likely to seek new and more energy intensive
methods of accessing water that have traditionally been too costly to attain.
Water budgets are of particular interest in the Los Angeles water/energy system. Despite
large water imports, substantial amounts of rainfall currently go to waste as surface run-off
through the City’s extensive flood control infrastructure. Due in part to reduced run-off, local
groundwater aquifers are millions of acre-feet short of capacity. The City of Los Angeles has
responded with integrated resource planning, committing to major investments in groundwater
recharge projects and water recycling.
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This chapter identifies three critical questions surrounding the water-energy nexus in
Southern California. First, is it possible to determine the energy profiles of different water
sources that provide water to the region using a spatially explicit life cycle assessment (LCA)
model? Life cycle assessment is a type of analysis that traces a product’s life history from
production to use and disposal (Guinee 2011). The life cycle assessment conducted in this
project is focused on the energy and GHG emissions impacts of different water supply resources
used by water districts in Southern California. Second, are certain sources less energy intensive
and therefore better alternatives than others? And third, how can the relationship between water
and energy inform future decisions in the face of growing demand? This chapter provides an
overview of the water-energy nexus in general and outlines the components of energy inputs for
transportation, treatment and distribution. It discusses the geographic sensitivity and variability
of related issues and synthesizes previous research on the topic. It then focuses on the specific
cases examined in this paper, the Los Angeles Department of Water and Power and the Inland
Empire Utility Agency, and outlines their water profiles. Also provided is a detailed discussion
of the data and methodology used to assess the energy footprint of water in Southern California.
This is followed by a section presenting the results and discussing their implications.
Background
Urban water scarcity is a critical and growing issue in Southern California. The Los
Angeles Department of Water and Power (LADWP) alone provided 562,480 acre-feet (AF) of
water in 2009, largely reliant on imported supplies (Los Angeles Department of Water and
Power 2010b). Water is provided to residential and commercial consumers by local utilities that
acquire their water from a range of sources, sometimes purchasing supplemental water from
other utilities in order to meet demand. This diversity of sources results in a highly dynamic
system where relatively small changes upstream can have significant effects on downstream
factors such and energy consumption and emissions (e.g. shifting a small volume of water
demand from one source to another can dramatically impact the energy required to transport the
water to a treatment facility). While this diversity can offer a measure of stability as individual
supplies struggle with variability, it also raises the need to evaluate the impacts of harnessing
water from each source. This study focuses on the energy and emissions associated with the
range of sources at various stages of the water distribution system. Figure 9.1, adapted from the
California Energy Commission’s 2005 report California’s Water-Energy Relationship, provides
an overview of California’s water consumption cycle. The dashed line delineates the project
system boundaries for this report, a critical component of any LCA-based model.
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Figure 9.1: Life cycle stages and project scope
Source: Adapted from California Energy Commission, 2005. California’s Water-Energy
Relationship. Figure 1-1.
California’s Water and Energy Nexus
Providing water to consumers requires significant amounts of energy. Delivering this
water requires energy inputs at three key stages: conveyance from the source to the treatment
plant (referred to in this report as transport); water treatment; and distribution to consumers, all
depicted in Figure 1. The California Energy Commission estimates that in 2001 water-related
energy use for the state of California totaled over 48,000 Gigawatt hours (GWh) of electricity,
approximately 19% of the state’s total electricity consumption, with water transport to Southern
California being over 50 times more energy intensive than to Northern California (California
Energy Commission 2005). This is largely due to the lack of reliable local water resources in
Southern California, where a large portion of the water is delivered from Northern California via
the State Water Project and from the Colorado River via the Colorado River Aqueduct. Given the
ways electricity is generated in California and indeed around the world, and in the context of the
growing threats of climate change (IPCC 2007), a discussion of energy consumption would be
incomplete without also examining the associated greenhouse gas (GHG) emissions. The
emissions from electricity consumption at various points along the water system vary drastically
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depending on the sources used to generate the electricity in question. Thus, not only is the
volume of the electricity inputs important, but the emissions profile of that electricity is also
critical from an environmental and, in the context of California’s landmark Global Warming
Solutions Act of 2006, from an economic standpoint.
Policy
The Global Warming Solutions Act, or AB 32, seeks to reduce GHG emissions to 1990
levels by 2020, a 25% reduction from 2006 levels (CARB 2012). Mandatory caps on emissions
from large sources, such as electricity utilities, took effect beginning in 2012, making reducing
emissions from electricity generation an increasing priority. Violations of the cap will be
enforced pursuant to state law, although penalties for failures to meet specific reduction
requirements have not yet been established, and therefore remain somewhat unclear. This
uncertainty can serve as further motivation to avoid penalties altogether. In addition, the state’s
forthcoming cap-and-trade program, which became operational on January 1st, 2012, offers
substantial market opportunities to those who comply with the cap. Simply stated, the case for
reducing emissions from electricity generation in California is strong. Similarly, large consumers
such as water utilities are unlikely to be exempt from the GHG emissions cap. Strategic planning
that incorporates the need to reduce the energy and emissions intensity of providing water will be
critical for avoiding penalties and taking advantage of this emerging market.
As impending water scarcity prompts utilities to pursue sources that are less accessible
and more energy intensive to harness and transport, the growing energy demand of providing
water to the region will inevitably produce greater GHG emissions. Investigating the specific
emissions profiles of attaining water from various sources as well as a deeper understanding of
the relationship between water and energy are critical when planning for a water- and carbonconstrained future.
Previous Studies
Several studies have examined the energy footprint of a particular water utility
(Wilkinson 2007) or of a region (Wilkinson 2000), but little work has been done to incorporate
emissions resulting from energy consumption at specific geographic scales. This is an important
component of a holistic approach to assessing the water-energy nexus and its implications.
Utilities have conducted or commissioned a number of studies investigating the energy,
and in some cases emissions, profiles of parts of their water distribution systems (Los Angeles
Department of Water and Power 2010b, IEUA 2009). While it is clearly beneficial for utilities to
understand their patterns of energy use and the energy intensity of different sources, their direct
benefits from a complete emissions profile are less clear. Regardless of motives, LAWDP
incorporated emissions factors into their most recent Urban Water Management Plan (2010b).
Their assumptions, emissions factors and methodology are questionable, as discussed further in
the next section.
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The Natural Resources Defense Council (NRDC) has also taken interest in California’s
vast and complex water-energy nexus. Their study, which focused on San Diego County, the
Westlands Water District and the Columbia River Basin, examined energy demands for water
use in an urban setting and for agriculture (Cohen, Nelson, and Wolff 2004). One of the most
relevant and important findings of this study is that water recycling is a highly energy efficient
source in the case of Southern California, where it generally offsets consumption of energy
intensive imported water.
Dr. Robert Wilkinson (UCSB) studied the opportunity for energy efficiency
improvements in California through the lens of water resource management. Wilkinson studied
the net embodied energy for selected water systems in California. This included
extraction/conveyance of imported water, extraction of local water resources,
treatment/distribution of potable water, and wastewater collection/treatment. He used these
findings of embodied energy to inform Best Management Practices for state water policy. In
2007, Wilkinson added the embodied energy of desalination and recycled water to this
methodology and analyzed the water supplies of the West Basin Municipal Water District. The
study determined that local groundwater and recycled water are among the least energy intensive
water supply options and that desalination will soon become as energy intensive as imported
water resources.
The California Energy Commission built on Wilkinson’s studies of the energy intensity
of water supplies to the Inland Empire Utilities Agency. In projecting water usage to 2030,
quantifying the energy required to produce water, and looking at end-use water efficiency, the
report identifies threats and opportunities for California’s water management in the future. While
there is not too much new analysis of embodied energy of water supplies, it does put into context
how relevant this research is and how it can be used by state/local governments. The water sector
is the biggest consumer of energy in the state of California; therefore, the study recommended
increased efficiency and investment in water resources to better take advantage of the synergies
that exist between the two resources as they continue to grow scarcer and more expensive.
(California's Water – Energy Relationship 2005)
After the California Energy Commission determined that approximately 20% of the state’s
energy usage was related to accessing water, the California Public Utilities Commission decided
to investigate the interdependency between water-energy systems by commissioning a study by
GEI/Navigant Consulting. Statewide and regional embodied energy of water was analyzed.
According to the study, groundwater extraction is a significant driver of electricity demand since
groundwater amounts to approximately 30% of the water supply across the state. Because much
of California’s water is imported from different regions (inter-basin transfers), the energy used to
access water regionally is significantly different from the embodied energy used to
produce/deliver the water. The study supports our findings on the importance of conveyance of
water when studying its energy intensity. The consultants modeled the energy impacts of future
water supplies, demands, and policies, but did not attempt to quantify the emissions associated
with these energy impacts.
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Many studies use the Emissions & Generation Resource Integrated Database (eGRID) to
calculate GHG emissions due to energy consumption. This is the EPA’s comprehensive database
that accounts for almost all emissions from power plants in the United States (EPA, 2011).
However, it is limited to combustion emissions occurring at the plants themselves and does not
take into account upstream or life cycle emissions attributable to electricity generation.
Coupling LCA and GIS
Life cycle assessment (LCA) is a powerful accounting tool for analyzing trade-offs and long
term benefits, and it broadens the understanding of interactions between various components of a
system. Coupling LCA with spatial analysis tools such as Geographical Information Systems can
offer new refinement to the LCA process. Other studies have coupled LCA with GIS for land use
analysis, biodiversity assessments, and even energy crop implementation (Gasol et al. 2011).
Additionally, LCA has been used to model energy and emission effects of water systems in
California, but very few studies address both tools in analyses of urban metabolism systems.
Ronald Geyer (2010) investigated the use of GIS with LCA in a study which assessed
land use and the effects on biodiversity. The findings show that the coupling produces a
meaningful measure of multidimensional environmental concerns. Various tools in GIS were
utilized in the LCA including, weighted overlay analysis, polygonal area calculations and
representation of geographical diversity. Geyer’s conclusions suggest that GIS might play a
valuable role in improving LCA’s lack of geographic differentiation.
Future LCA models can utilize GIS to reinforce various input-output data. In addition,
LCA can influence GIS models creating a synergy between the two environmental tools. Life
Cycle Inventory (LCI) can integrate effectively with spatially explicit data allowing for
geographic representation of dynamic systems.
Case Studies
When examining the water-energy nexus within a region, it is often most practical and
meaningful to do so at the level of the utilities, for which data are tracked and readily available.
For this project, we analyzed the energy and GHG emissions of different water sources for two
water districts, the Los Angeles Department of Water and Power, and the Inland Empire Utilities
Agency, for which we were able to obtain needed data in a timely way. In Southern California,
no city embodies the challenges posed by the growing interdependence of water and energy more
fully than Los Angeles. LADWP, the city’s major utility, provides water to about four million
consumers in and around Los Angeles (Los Angeles Department of Water and Power 2010b). In
2009, LADWP delivered 562,480 acre-feet of water to its customers. LADWP’s water comes
from four main sources: local groundwater, recycled water, through the Los Angeles Aqueduct,
which it owns and operates, and imported water. The Inland Empire Utility Agency (IEUA)
serves approximately 850,000 residents in southwest San Bernardino County, a much smaller
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service area than that of LADWP (IEUA 2005). In 2009 IEAU delivered 220,550 acre-feet of
water to its customers. The IEUA’s water supply profile shares a similar mix of water supply
sources and energy mix as the Cucamonga Valley Water District. As a result, findings on the
energy intensity and associated GHG emissions for the IEUA will be applicable to CVWD.
In the case of both LADWP and Inland Empire, the imported water is supplied by the
Metropolitan Water District of Southern California (MWD). MWD, in turn, imports its supplies
from Northern California through the California Aqueduct and from the Colorado River via the
Colorado River Aqueduct (MWD and LADWP 2008).
LADWP
Due to the water demand of its four million customers, LADWP must rely on numerous
sources. This adds to the complexity of the agency’s water-energy nexus. The energy footprint
of the water depends on the source and various processes along the way to the consumer. Thus,
each source requires different energy inputs at different stages; in short, in terms of energy, all
water is not created equal. For example, the ground water used by LADWP requires
approximately 530 kilowatt hours per acre-foot (kWh/AF) to be transported to the treatment
plant and another 61 kWh/AF for treatment. By contrast, imported water from MWD’s Colorado
River Aqueduct requires about 2,000 kWh/AF for transportation but only 27 kWh/AF for
treatment. These discrepancies exist between each source, and even among specific sources
imported from MWD. After treatment, all the water is distributed in the same way regardless of
source, so distribution requires the same amount of energy for water from all sources, 196
kWh/AF for LADWP. The map in Appendix 1 provides an overview of LADWP’s infrastructure
and service area.
IEUA
Unlike LADWP, which fulfills a large portion of demand with its own imports, IEUA’s
imports are strictly from MWD. This water accounts for approximately 25% of demand. The
agency does operate its own groundwater desalination, recycling and surface water treatment
facilities, which meet the remaining 75% of demand. When founded in 1950, the agency was
strictly responsible for supplying supplemental water through imports from MWD (GEI
Consultants/Navigant Consulting 2010). Although the agency’s sources have expanded over the
past six decades, IEUA’s water source profile represents a much smaller range than LADWP’s.
The map in Appendix 2 provides an overview of IEUA’s infrastructure and service area.
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Data and Methods
In order to assess the energy and emissions impact of LADWP and IEUA, data were
required from a number of sources. The water utilities provided numerical and geospatial data
about their water sources and the energy inputs at each stage. The electricity utilities’ statemandated power content labels were used to determine the grid mixes of each utility. The
emissions factors of electricity generated from each source were based on a literature review of
life cycle assessments. Pumping and treatment plant electricity sources were determined based
upon email and telephone correspondence with LADWP and IEUA. In cases where a power
utility could not be specifically identified, we used data from the Emissions & Generation
Resource Integrated Database (eGRID), which has GHG emissions profiles for major subregions
of the United States. For California, EGRID uses the WECC California subregion, which
encompasses most of the state. GHG emission factors for this subregion as known as the CAMX
model. Finally, the projected scenarios were based on water demand projections from the water
utilities and grid mix projections from the electricity utilities.
Water Sources
In order to determine the overall impact of each source, it was imperative that accurate
estimates of delivered water volume were gathered from the utilities. This enabled calculating
the contribution of each source to the energy consumption and emissions of the entire system.
Focusing on LADWP, the Los Angeles Aqueduct and State Water Project West provide the
majority of the utility’s water supply, shown in Table 9.1. In the case of Inland Empire, the water
supply is relatively evenly distributed with Chino Groundwater providing the bulk of the water,
shown in Table 9. 2. All water data were derived from published reports by the water utilities and
represent consumption levels for 2009 as well as projections of future demand.
Table 9.1 LADWP delivered volume in 2009
Water Sources
Los Angeles Aqueduct
State Water Project West1
State Water Project East1
Colorado River Aqueduct1
Groundwater
Recycled water
Total
1
Imported from MWD
LADWP - Volume (AF)
137,084
270,653
45,246
37,012
64,996
7,489
562,480
Source: LADWP, 2010. Urban Water Management Plan.
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Table 9. 2 IEUA delivered water volume in 2009
Water Sources
IEUA –Volume (AF)
Tier I/II (Imported MWD)
37,975
1
DYY - Dry Year Yield
16,959
Chino Groundwater
68,277
Recycled Water
15,226
Other Groundwater
31,035
Surface Water
36,341
Desalinated (Chino Desalter)
14,737
Total
220,550
1
Additional Chino Basin Groundwater
Source: IEUA, 2009. Annual Water Use Report.
Energy Intensity
For the purposes of this analysis, LADWP’s Urban Water Management Plan provided a
basis for determining the energy required for different water resources including groundwater,
recycled water and water from the California, Colorado River, and Los Angeles Aqueducts.
Energy required to pump, treat, and distribute the water were included in the calculation of each
source’s energy intensity (kWh/AF).
One important distinction to note is how hydroelectric power generation is treated for
different sources. Both the LAA and CRA generate power, however the LAA is gravity-fed
while the CRA is pumped to a higher elevation before generating electricity. Therefore, the
energy intensity of the LAA is treated as zero, because it is a net generator of electricity but does
not directly offset the energy used for water resources. The CRA is a net consumer of electricity,
but receives credit for its electricity generation since this is a by-product of pumping the water
along the aqueduct. Generally, if electricity is generated as a result of pumping the water it is
counted as a credit, but no water source can be a net generator of electricity.
Emissions data
Utilities’ Energy Portfolio Emissions with Life Cycle Assessment
To estimate both the direct and indirect emissions associated with the various energy
sources (e.g. coal, hydropower, solar, etc) that the three utilities use to generate electricity, we
conducted a literature review of life cycle assessment studies for each energy source. To select
appropriate studies we used a number of suitability criteria, guided by the overarching goal of
approximating LADWP, Southern California Edison, and City of Riverside energy supply
portfolios. First, whenever possible, we selected studies that were geographically specific to
those same regions that supply power to Southern California. For this reason, we did not include
LCA studies of offshore wind power, for example. Second, since we wanted to include both
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direct and indirect emissions, we selected studies that conducted “cradle-to-grave” analyses, that
is the system boundary of these studies included emissions associated with construction, on-site
erection and assembly, production, transport, waste and disposal. However, we excluded those
studies that include the emission reduction benefits of carbon capture sequestration and storage.
Third, we selected studies that were similar to the output capacities and life expectancy of the
facilities currently or projected to supply the three utilities with power. Again using the wind
power example, we compared to ensure similar output capacity. Despite these efforts to ensure
consistency and comparability with these LCA studies, we do recognize that system boundaries,
scopes, and assumptions differ somewhat between LCA studies. Therefore, we averaged the
results of the studies selected to obtain a CO2 equivalent average for each kilowatt hour
generated as shown in Table 9.3. We assumed each kilowatt of electricity supplied by the
utilities is uniform in composition for each utility; for example, for LADWP, each kilowatt is
composed of 41% coal, 30% natural gas, 11% nuclear, and so on. While this analysis focused
exclusively on LADWP, the emissions factors for each energy source can be utilized when
assessing the emissions profiles of the other two utilities. This is justifiable given the innate
characteristics of the fuel sources and the proximity of Southern California Edison and City of
Riverside generating facilities to those of LADWP. For these reasons, any differences in life
cycle emissions are negligible.
We relied on one particularly useful compendium published by the National Academies,
Electricity from Renewable Resources (2010) which provides a literature review of LCA studies
conducted for each major energy source. Using this compendium as a guide, we selected suitable
studies based on our selection criteria and augmented them with studies that we found based on
our own literature review. Below, Table 9.3 provides summary notes for major non-renewable
and renewable energy sources.
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Table 9.3: Estimated emissions for selected energy sources
Energy source
CO2e
SOx
NOx
PM
(g/kWh)
(g/kWh)
(g/kWh)
(g/kWh)
Non-renewables:
Coal
1005
7
3.4
9.8
Natural gas
493.5
0.32
0.57
0.13
Nuclear
20
0.032
0.07
0.007
Biomass & waste
33.5
0.37
0.65
0.03
Geothermal
15
0
0
0
Hydroelectric (small)
11
0.027
0.074
0.005
Hydroelectric (large)
254
0.37
0.65
0.03
Solar PV
46
0.37
0.18
0
Wind
15.5
0.032
0.048
0.004
Renewables:
Source: Authors’ calculation based on a literature review of studies in National Academies
(2010). Electricity from Renewable Resources: Status, Prospects, and Impediments.
Nonrenewable energy sources
For coal emissions, we used studies of traditional pulverized coal-plants (Denholm 2004,
Hondo 2005, Odeh and Cockerill 2008, Spath and Mann 2004, Spath, Mann and Kerr 1999).
Although excluded in our study, studies show that new technologies such as low-emissions
boiler systems, emission rates may drop from 757 to 879 g CO2e/kWh in the future. Studies of
natural gas included those by Denholm (2004), Hondo (2005), Meier (2002), Odeh and Cockerill
(2008), and Spath and Mann (2000). Plant efficiency and natural gas losses from production and
distribution affect natural gas emission profiles. Studies of nuclear power related emissions
include those by Denholm (2004), European Commission (1997a), Fthenakis and Kim (2007),
Hondo (2005), Storm van Leeuwen (2008), Vattenfall AB (2004), and White (2006). For nuclear
power, the range of values is from 15 to 25 g CO2e/ kWh. We excluded two studies that we
significantly beyond this range, including the study of Swedish reactors by Vattenfall AB (2004),
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which had a value of 2 g CO2e/ kWh and the study by Storm van Leeuwen (2008), which using
EIO methods, had a value of 108 g CO2e/ kWh due to use of gas diffusion to enrich the fuel.
Renewable energy sources
For biomass emissions we used studies by Berry et al. (1998), European Commission
(1997a) (1997b) (1997c) (1997d), Mann and Spath (1997), Spath and Mann (2004), and Spitzley
and Keoleian (2005). Factors that affect CO2e emissions include the yield, the fertilizer and fuel
used to harvest the feedstock, as well as differences due to the type of plant facility. Studies of
facilities that burned waste to generate energy where excluded, but Spath and Mann (2004)
actually found significant greenhouse gas sink potential (15 to 52 g CO2e/kWh) for waste-energy
conversion due to the carbon credits associated with the avoided landfill-related GHGs.
Geothermal studies included those by
CO2e emissions associated with geothermal energy (Bertani and Thain 2002, Bloomfield,
Moore and Neilson 2003, Hondo 2005, Serchuk 2000) vary considerably depending on reservoir
gas composition and if during the generation the gas is vented to the atmosphere. Emissions
associated with hydroelectric power (Gagnon and van de Vate 1997, Hondo 2005, Spitzley and
Keoleian 2005) are particularly controversial because when a dam is constructed, newly flooded
biomass decomposes and is a source of greenhouse gas emissions. Hoover and Oahe’s full
cradle-to-grave emissions study of large (>30 MW) hydroelectric power plants in the United
States included emissions associated with construction, flooded biomass and the eventual
decommissioning of the dam. Emissions associated dam decommissioning was normalized to the
total electricity produced over the lifetime of each power plant.
Emissions from solar energy vary based on the energy grid mix used to generate the
electricity necessary to manufacture photovoltaic modules and plant facilities. Emission rates per
unit of electricity generated are related to solar panel conversion efficiencies. Studies of solar
included those by Denholm (2004), European Commission (1997a), Frankl, Corrado and
Lombardelli (2004), Fthenakis, Kim and Alsema (2008), Hondo (2005), Meier (2002), and
Spitzley and Keoleian (2005).
For wind energy emissions, we included studies by Chataignere and Le Boulch (2003),
Chataignere et al 2003b, Chataignere et al 2003c, Denholm (2004), European Commission
(1997a), Hondo (2005), Spitzley and Keoleian (2005), Spitzley and Keoleian 2005b, Spitzley
and Keoleian 2005c, and White (1998).
Utilities’ emissions factors & methodology
LADWP uses either eGRID or CCAR (now, the Climate Registry) methodology to calculate its
emissions factors, depending on the source of the water. eGRID is a database of environmental
emissions for almost all electric power plants generating in the United States that can be
aggregated to estimate California’s regional emissions from electricity. CCAR is a non-profit
organization which has created a standardized method for calculating, reporting, and verifying
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GHG emissions, in which LADWP participated during 2007. For imported sources of water, the
2007 CAMX (Western Electricity Coordinating Council California Subregion) average carbon
emission of 0.72412 lbs CO2/kWh (this is only CO2, CH4 and N2O are not taken into account)
is used to estimate carbon emitted per unit electricity. For local sources of water, the emissions
factor LADWP reported to the California Climate Action Registry in 2007 (1.22789 lbs
CO2/kWh) was used to estimate the carbon intensity of power consumed.
The assumption is that electricity used for pumping, treatment, and distribution of the
water either comes from LADWP or CAMX, depending on the source of the water. CAMX is a
NERC sub-region encompassing parts of California, Nevada, and Arizona. It estimates
energy/emissions from the entire region and applies them to the imported water. Renewable
energies (wind, solar, hydroelectric, nuclear, and biomass) are treated as carbon-neutral by both
eGRID and CCAR, while geothermal energy has a low carbon burden. The CCAR emissions
factor is likely higher because it takes into account transmission/distribution losses and accounts
for CH4 and N2O emissions from electricity generation, whereas eGRID does not.
GIS Data Sources and Methodology
Merging emissions and energy data with spatially explicit water infrastructure data required the
use of a Microsoft Excel-based model to calculate the unique energy profile for each water
source. Figure 9.2 provides a conceptual overview of the model. Incorporating utility specific
power content labels and the literature review of the LCAs for each energy source allowed the
model to adjust depending on changing water demand and electricity grid mixes. As power
content labels and water demand levels change over time the emissions for each water source are
adjusted. Integrating energy and emission attribute data into a spatially explicit format required
the use of geocoding the attribute data with existing GIS data from the various utilities. The
methodology for the geocoding process for MWD is described below.
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Figure 9.2: Water/Energy profile and utility emissions conceptual model
Primary GIS data came from the Municipal Water District (MWD) of Southern
California. MWD provided pipeline infrastructure, water treatment plants, and Colorado River
Aqueduct pumping stations. This data was then joined to the Excel-based model using ESRI
ArcGIS 10x. In order to link the utility, consumption, energy intensity and emissions data to the
geospatial data a unique identifier key was generated in the GIS data using the pipeline FF Code
and the water type (“Treated” or “Untreated”). The pipeline data was then dissolved1 from over
140,000 individual segments down to 215 segments using the FFCODE data and the water type
attributes.
The dissolved GIS data were then analyzed using spatial proximity to the treatment and
pumping stations. Each of the 215 segments was assigned a pumping or treatment plant based on
its location and topography. For example, all water segments between the Iron Horse Pumping
Station and the Eagle Mountain pumping station were assigned the Iron Horse value because of
the westward flow of water into Los Angeles. In some circumstances, it was unclear for a
segment which treatment plant treated that particular section of pipeline, in such cases, a best
guess assumption was made based on the proximity and origin of surrounding pipeline.
1
Dissolve or dissolution is a GIS aggregation process whereby data with a common category value is merged.
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After treatment/pumping plants were assigned to each segment of pipeline, the Excel
model populated the attribute table with the synthesized utility, emissions and power
consumption data. The attribute table was joined in ArcGIS and natural jenks classifications2
were used to represent the symbology for each pipeline segment.
Additional data were developed using published maps from the State Water Project East
and West. The maps were built using geo-referencing tools as well as hydrologic basemaps
provided by ESRI. Geo-Code information for the LADWP power systems generation and power
plants was available from the California Energy Commission Energy Almanac.
Energy and Emission Factors
The geospatial linked data model was developed for the purpose of assigning energy and
emission factor attributes to the MWD, LADWP and SWP GIS data. The goal of this model was
to establish a dynamic relationship between emission factors, energy consumption and geospatial
attributes. The model was constructed using an Excel-based table and was exported to ArcGIS
10.1 using a table join with the FFCODE and water type as a unique identifier key. A dynamic
relationship allows the model to be run under different scenarios of energy consumption,
emissions, and grid mixes to show how improvements will affect the footprint of delivered
water.
This model was constructed based on the emission factors, by generation source, based
on the literature of the LCA studies as noted earlier in the report.). Reported energy mixes for
each utility were used to calculate the total CO2e, SOx, NOx, and PM emissions for each
kilowatt hour of electricity produced per utility. Specific plant data acquired from MWD and
LADWP for the kWh requirement per acre-foot of water pumped or treated was used to calculate
the energy and emission footprint of delivered water.
Table 9.4 outlines the utilities and their reported generation mix, as well as EPA’s eGRID
California energy mix, or CAMX. CAMX was used for the State Water Project East and West,
which are beyond the scope of the Los Angeles area utilities power grid. Using a statewide
average provided an appropriate approximation for assigning a grid mixture to the electrical
inputs for the State Water project which expands nearly two thirds across the state. Data were not
available for the Cucamonga Valley Water District, so we used energy sourcing profiles for the
City of Riverside, which as an example lists approximately 17% of their electricity as being from
unspecified sources. In this case, the CAMX grid mix was used, proportionally increasing their
reported percentage from those sources.
2
In GIS, the Jenks Optimization Method is a data classification method used to determine the best arrangement of
values into different class categories.
229
Table 9.4: Grid mix portfolios
Southern
California Edison
(2009)1
LADWP
(2009)2
City of
Riverside
(2010)3
eGRID
CAMX
(2007)4
Coal
15%
41%
55%
9%
Natural gas
38%
30%
6%
53%
Sub-total
53%
76%
61%
62%
Biomass & waste
2%
2%
1%
2%
Geothermal
9%
1%
17%
4%
Hydroelectric
(small)
1%
6%
1%
1%
Hydroelectric
(large)
9%
4%
2%
11%
Solar
1%
0%
1%
0%
Wind
4%
5%
1%
3%
Nuclear
21%
11%
16%
16%
Sub-total
47%
18%
39%
38%
100%
100%
100%
100%
Energy Source
Non-renewables:
Renewables:
Total
1
Southern California Edison, 2009 Power Content Label (2010)
2
Los Angeles Department of Water and Power (2010a)
3
City of Riverside (2011)
4
EPA (2011)
230
Water Sourcing and Analysis
Water delivered to the Los Angeles basin comes from five sources: the Colorado River via the
Colorado River Aqueduct; the Owens River via the Los Angeles Aqueduct; Northern California
via the State Water Project (West and East Branches); groundwater; and water recycling. In
order to spatially analyze the energy and emission footprint of delivered water the network was
broken into two categories and five sections per category. The first category was water transport
system; Table 9.5 outlines the water delivery system and the delivered emission values.
Table 9.5: Category 1 - transport system
Delivery System
Colorado River Aqueduct
Los Angeles Aqueduct1
KWh/AF
Electricity
Supplier
2,000
SCE
-
eGRID – CAMX2
State Water Project
1
East
3,236
West
2,580
Groundwater
530
LADWP
Recycled Water
1328
LADWP
Los Angeles Aqueduct is gravity fed, no energy input is required
2
eGRID energy mix was used for SWP because energy inputs span over a large geographic area
of California across multiple utilities
The second category was water treatment system. Each water treatment system required a water
transport system to be assigned. Table 9.6 outlines the breakdown and assignment of transport
systems for each treatment system (Claisse 2011).
231
Table 9.6: Category 2 - treatment system
Water Treatment Plant
Electricity
Supplier CRA LAA SWPE SWPW GW
Total
Robert A. Skinner
SCE
100%
Joseph Jensen
LADWP
F.E. Weymouth
SCE
45%
55%
100%
Robert B. Diemer
SCE
45%
55%
100%
Henry J. Mills
CoR
100%
100%
LAAFP1
LADWP
Recycled Water2
LADWP
45%
55%
100%
55%
100%
45% 100%
0%
1
Los Angeles Aqueduct Filtration Plant
2
Water Reclaimed After delivery, use, and waste treatment
A weighted average of the transport system was used to determine the total energy and
emissions footprint of delivered water to each treatment system. The energy required to treat the
water was then added to the transport energy to represent the total energy and emissions intensity
per acre-foot of treated delivered water.
Projections
Due to the RPS that mandates 33% electricity generation be from renewable sources by
2020, utilities in California have had to submit plans for meeting this target. Long Term
Procurement Plans and Power Resource Plans have been released to the public through the
California Public Utilities Commission. Due to the sensitive nature of procurement plans and
unpredictable fuel prices, most companies can only release information about their intended
renewable generation sources. Based on these projections, future grid mixes for the City of
Riverside, SCE, and the state of California were calculated for 2020. LADWP released a Power
Integrated Resource Plan in 2011 that projected their energy resources through 2030.
Projections of water demand are also necessary for local utilities in determining how to
ensure reliable water supply. Given the scarce nature of the resource, LADWP and IEUA have
released Urban Water Management Plans that track changing demographics, populations, and
water usage and project these trends to 2030. Unless otherwise stated, we assume a constant
232
distribution of water resources over time as demand increases. Thus, we can illustrate the
changing emissions profile of Los Angeles’ water demand through 2030.
Results and Discussion
Utilizing the model to process the water data, energy data and LCA-based emissions
factors, we determined energy and emissions profiles for LADWP and IEUA by individual water
source. These results are presented below, along with the projected energy and emissions profiles
for LADWP in 2020 and 2030 under two water conservation scenarios. The map in Appendix 3
presents the energy profiles of the water sources relied on by both utilities in 2009.
LADWP
Based on delivered water volume for 2009 and data from 2010 for the electric utilities’
energy mixes, the model developed for this study determined that LADWP consumed 1,076
GWh to deliver 555,000 AF of water, emitting 438,000 tons of CO2e. Table 9.7 provides a
detailed breakdown of LADWP’s energy and emissions profile for 2009.
Table 9.7: LADWP Profile 2009
Sources
AF/YEA
R
Allocation
kWh/AF
Total Energy
[kWh/Year]
CO2e
[Tons/AF
]
CO2e
[Tons/Ye
ar]
LAA
135,153
24%
230
31,129,488
0.13
17,704
SWP West*
266,841
48%
2,817
751,569,988
1.11
296,300
SWP East*
44,609
8%
3,459
154,319,148
1.35
60,015
CRA*
36,491
7%
2,223
81,133,165
0.84
30,770
Groundwat
er
64,081
12%
726
46,522,510
0.41
26,459
7,384
1%
1,524
11,252,491
0.87
6,399
Recycled
Totals
554,558
1.00
1,940
*Imported from MWD
233
1,075,926,791
0.79
437,648
Overall, water imported via the State Water Project East had the highest energy and
emissions burden. Total energy and emissions intensity was a function of these inputs at three
distinct stages of water delivery: transport from the source, treatment, and distribution to
consumers. The transport component is by far the largest contributor to energy and emissions
intensity, and varies greatly between sources. Transporting water via the SWP East, for example,
requires 3,236 kWh/AF to move the water over the Sierra Nevada Mountains, while utilizing the
Los Angeles Aqueduct, which is gravity fed, requires no net energy input. Recycling water and
pumping groundwater also require substantially less energy than importing supplies from all of
LADWP’s sources other than the LAA.
Due to low transport energy requirements, the Los Angeles Aqueduct is the least energyintensive source used by LADWP, at 230 kWh/AF. As a result of general similarities in the
emissions intensity of electricity generation, the emissions profiles follow a similar pattern to the
energy profiles for all sources. This relationship between energy and emissions, however, is not
strictly linear – the emissions from electricity generation depend upon the source used to
generate electricity. As a result of the electricity consumed from transport to distribution, the
LAA, groundwater and recycled water are all responsible for the greatest amount of CO2e
emitted per kWh consumed. While these sources required less energy per acre-foot than the
water imported from MWD, the electricity used was more emissions-intensive. Conversely, the
electricity required by the CRA emitted the least amount of CO2e per kWh. Although this is an
energy-intensive source, the electricity grid mix of the utilities on which the CRA relies is
cleaner than all the utilities relied on by all the other sources.
The energy and emissions associated with treatment depends upon the individual
treatment plant through which the water passes on its way from the source to the consumer.
While the energy required to treat an AF of water varies between plants, the relative magnitude
of this energy input is negligible compared to the total energy. Currently, the Diemer Treatment
Plant only utilizes 15 kWh/AF while the Mills plant requires 64 kWh/AF to treat water. Water
from different sources mix at the treatment plants depending on a given plant’s location and
proximity to the water transport systems (i.e. the various aqueducts). The proportion of water
from different sources that arrives to each treatment plant depends on variable conditions such as
annual rainfall and seasonal demand. Thus, these calculations were based on average estimates
provided by MWD (cite).
Once the water has been treated, it requires an average of 196 kWh/AF for distribution.
This average applies to all LADWP water, as the distribution process is identical regardless of
the treatment plant the water passed through or its original source. In essence, once water arrives
for distribution, it is all on “even footing” with respect to energy and emissions requirements.
While this energy input is substantially higher than the energy required for treatment, it is an
order of magnitude less than what is required for transport from most sources that supply
Southern California and LADWP consumers. Figure 9.3 shows the emissions profile of LADWP
by each source’s proportional contribution in 2009.
234
Figure 9.3: LADWP proportion of CO2e emissions by source, 2009
100%
1%
4%
6%
90%
7%
80%
14%
Recycled
70%
60%
Los Angeles Aqueduct
50%
Groundwater
40%
Colorado River Aqueduct (imported from MWD)
68%
30%
State Water Project East (imported from MWD)
20%
State Water Project West (imported from MWD)
10%
0%
The emissions associated with energy use at each step are directly dependent upon the
utility supplying the electricity. Since the grid mix of primary energy sources utilized by each of
the three utilities supplying electricity for pumping, treatment and distribution varies for each
utility, the emissions profiles are not identical. For example, a kWh of electricity generated by
Southern California Edison is associated with the emission of 361 grams of CO2. The same
amount of electricity generated at City of Riverside is responsible for 588 grams of CO2. Still,
given the relative magnitude of energy consumption for transport, the distance and terrain
involved in transport from a particular source, rather than the specific utility providing the
electricity, should be the primary concern in terms of emissions. In the case of LADWP, the
amount of electricity consumed – determined by the source – rather than how that electricity is
235
generated, is the largest factor in determining the emissions from supplying water to consumers.
Figure 9.4 shows LADWP’s emissions by source, both on a per acre-foot basis and the annual
total.
350
1.60
300
1.40
1.20
250
CO2e [Tons/Year]
1.00
200
0.80
150
0.60
100
CO2e [Tons/AF]
Thousands
Figure 9.4: LADWP CO2e emissions by source, 2009
0.40
50
0.20
0
0.00
Los Angeles State Water State Water
Aqueduct Project West Project East
(imported
(imported
from MWD) from MWD)
Colorado Groundwater
River
Aqueduct
(imported
from MWD)
CO2e [Tons/Year]
Recycled
CO2e [Tons/AF]
IEUA
Based on delivered water volume for 2009 and data from 2010 for the electric utilities’
energy mixes, IEUA consumed 251 GWh of electricity to deliver 221,000 AF of water, emitting
92,000 tons of CO2e. Table 9.8 provides a detailed breakdown of IEUA’s energy and emissions
profile.
236
Table 9.8: IEUA Profile 2009
Source
CO2e
[Tons/A
F]
CO2e
[Tons/Yea
r]
AF/YEA
R
Allocatio
n
SWP East*
37,975
17%
3,496
132,769,461
1.32
50,048
DYY**
16,959
8%
570
9,666,630
0.21
3,489
Chino
Groundwater
68,277
31%
570
38,917,890
0.19
13,304
Recycled
Water
15,226
7%
1,416
21,559,584
0.51
7,782
Other
Groundwater
31,035
14%
570
17,689,950
0.21
6,385
Surface
Water
36,341
16%
220
7,995,020
0.08
2,886
1,505
22,182,314
0.54
8,006
Desalinated
(Chino
Desalter)
14,737
Totals 220,550
kWh/AF
Total Energy
[kWh/year]
7%
100%
1,137
250,780,849
0.42
91,900
*Imported from MWD
** Dry Year Yield (Additional Chino Basin Groundwater)
As with LADWP, water imported from State Water Project East was the most energy and
emissions intensive, requiring nearly 3,500 kWh to deliver one acre-foot, the overwhelming
majority of which was required by the transport stage. By contrast, at 220 kWh/AF, surface
water was the least energy- and emissions-intensive source. This was due primarily to the low
transport needs of local surface water that does not need to be pumped out of the ground or
transported great distances.
The relative significance of the transport component is underscored by IEUA’s energy
and emissions with respect to MWD. Only 17% of IEUA’s water is imported from MWD, but
this water is responsible for over slightly 50% of IEUA’s entire energy profile and nearly 60% of
their emissions profile. Figure 9. 5 shows the emissions profile for IEUA by each source’s
proportional contribution in 2009. Figure 9.6 shows the emissions profile both on a per acre-foot
basis and the annual total.
237
Figure 9. 5: IEUA proportion of CO2e emissions by source, 2009
100%
3%
4%
90%
7%
8%
80%
Surface Water
9%
70%
Surface Water
14%
60%
Dry Year Yield (Additional
Chino Basin Groundwater)
50%
Recycled Water
40%
Desalinated (Chino Desalter)
30%
54%
Chino Groundwater
20%
Tier I/II (Imported MWD)
10%
0%
.
By comparing the two utilities, it becomes clear that there are substantial disparities between the
energy and emissions burdens of providing water to Southern California from different sources.
LADWP provides 2.5 times more water than IEUA, but requires 4.5 times more energy and
emits 5 times more CO2e emissions. The higher energy use is directly related to the utilities’
water source profiles. The differences in emissions are caused both by the varied energy needs of
providing water from each source as well as the specific electricity grids relied on to deliver and
treat the water.
238
Figure 9.6: IEUA CO2e emissions by source, 2009
60
1.40
1.20
50
1.00
0.80
30
0.60
CO2e [Tons/AF]
CO2e [Tons/Year]
40
20
0.40
10
0.20
0
0.00
Tier I/II DYY - Dry Year
Chino
(Imported
Yield
Groundwater
MWD)
(Additional
Chino Basin
Groundwater)
Recycled
Water
Other
Groundwater
Surface
Water
Desalinated
(Chino
Desalter)
CO2e [Tons/Year]
CO2e [Tons/AF]
Projected Scenarios for LADWP
LADWP’s projections for future water demand at two time points – 2020 and 2030 – are
based on two scenarios, one in which passive conservation methods are utilized and another in
which both active and passive conservation3 measures are employed. Additionally, these
projections utilize projections by the electric utilities of their anticipated grid mixes. Southern
California Edison and City of Riverside only project to 2020 – in these cases, the 2020 mix is
applied to the 2030 scenarios as well. LADWP does project to 2030 – thus, this projection is
applied to the appropriate scenarios.
3
Passive water conservation measures according to LADWP include measures such as educational programs, and
active measure include strategies such as metering, rebates, pricing.
239
2020 Projections: Passive Conservation
Using LADWP’s demand projections for 2020 with only passive conservation measures,
and the electric utilities’ projected grid mixes, total electricity consumption was determined to be
1,265 GWh to deliver 652,000 AF of water, emitting 359,000 tons of CO2e. While the amount of
delivered water and the energy required by the utility both increase modestly from 2009, the
overall CO2e emissions decrease by 18%. This is due to the substantial adoption of renewable
energy sources expected by the electric utilities by 2020.
Table 9.9: LADWP 2020 passive conservation
Source
AF/YEA
R
Allocatio
n
kWh/AF
Total Energy
[kWh/Year]
CO2e
[Tons/A
F]
CO2e
[Tons/Year]
LAA
158,904
24%
230
36,600,015
0.09
14,944
SWP
West*
313,734
48%
2,817
883,646,801
0.77
241,240
SWP East*
52,448
8%
3,459
181,438,353
0.93
48,797
CRA*
42,903
7%
2,223
95,391,065
0.60
25,873
Groundwat
er
75,342
12%
726
54,698,123
0.30
22,333
8,681
1%
1,524
13,229,943
0.62
5402
652,013
100%
1,940
1,265,004,300
0.55
358,589
Recycled
Totals
*Imported from MWD
2020 Projections: Passive & Active Conservation
Under LADWP’s demand projections for 2020 that incorporate both active and passive
conservation measures, the utility will consume 1,208 GWh to deliver 623,000 AF of water,
emitting 342,000 tons of CO2e. Since both the energy intensity of each source and the emissions
intensity of electricity from each electric utility remain constant between the two projected
240
scenarios for 2020, the reduced water consumption leads to a proportion decline in expected total
CO2e emissions.
Table 9.10: LADWP 2020 passive & active conservation
Source
AF/YEA
R
Allocatio
n
kWh/AF
Total Energy
[kWh/Year]
CO2e
[Tons/AF]
CO2e
[Tons/Yea
r]
LAA
151,768
20%
230
34,956,415
0.09
14,273
SWP West*
299,645
48%
2,817
843,964,804
0.77
230,406
SWP East*
50,093
8%
3,459
173,290,487
0.93
46,606
CRA*
40,977
7%
2,223
91,107,331
0.60
24,711
Groundwate
r
71,958
12%
726
52,241,790
0.30
21,331
8,291
1%
1,524
12,635,825
0.62
5,159
622,733
100%
1,940
1,208,196,650
0.55
342,486
Recycled
Totals
*Imported from MWD
2030 Projections:Passive Conservation
Using LADWP’s demand projections for 2030 with only passive conservation measures,
and the electric utilities’ projected grid mixes, total electricity consumption was determined to be
1,360 GWh to deliver 701,000 AF of water, emitting 355,000 tons of CO2e. Again, while the
amount of delivered water and the energy required by the utility both increase modestly from
2020, the overall CO2e emissions decrease slightly. This is due entirely to LAWDP’s
replacement of all remaining coal generation with natural gas between 2020 and 2030.
241
Table 9.11: LADWP 2030 passive conservation
Source
AF/YEA
R
Allocatio
n
kWh/AF
Total Energy
[kWh/Year]
CO2e
[Tons/AF]
CO2e
[Tons/Yea
r]
LAA
170,883
24%
230
39,359,051
0.06
10,363
SWP West*
337,385
48%
2,817
950,259,160
0.73
247,853
SWP East*
56,402
8%
3,459
195,115,801
0.90
50,873
CRA*
46,138
7%
2,223
102,581,974
0.57
26,512
Groundwate
r
81,021
12%
726
58,821,457
0.19
15,488
9,336
1%
1,524
14,227,262
0.40
3,746
Recycled
Totals
701,164
100%
1,940
1,360,364,709
0.51
354,836
*Imported from MWD
2030 Projections: Passive & Active Conservation
Under LADWP’s demand projections for 2030 that incorporate both active and passive
conservation measures, the utility will consume 1,250 GWh to deliver 644,000 AF, emitting
326,000 tons of CO2e. As with the two projections for 2020, everything remaining constant
between the two 2030 projections except amount of delivered water. Thus, the decline in total
energy and emissions are due solely to reduced consumption.
242
Table 9.12: LADWP 2030 passive & active conservation
Source
AF/YEA
R
Allocatio
n
kWh/AF
Total Energy
[kWh/Year]
CO2e
[Tons/AF]
CO2e
[Tons/Yea
r]
LAA
156,899
24%
230
36,138,201
0.06
9,515
SWP West*
309,776
48%
2,817
872,497,081
0.73
227,571
SWP East*
51,786
8%
3,459
179,148,992
0.90
46,710
CRA*
42,362
7%
2,223
94,187,435
0.57
24,342
Groundwate
r
74,391
12%
726
0.19
14,221
Recycled
8,572
1%
1,524
0.40
3,440
Totals
643,786
100%
1,940
54,007,950
13,063,009
1,249,042,670
0.51
325,799
In this section we have demonstrated how the analysis of energy and emissions intensity
of water supply sources could be incorporated into UWMP plans to take into account the
multiple objectives of California’s environmental policy.
Incorporating Energy and Emissions Intensity into Analysis and Plans for Water Supply
Initiatives
The type of analysis conducted in this chapter could be used to provide more specific
guidance to water agencies on the water supply options they are considering for capital
investment. For example, groundwater storage, which the LAEDC study (2008), briefly
reviewed in Chapter 1, estimated had a 30-year $ cost per acre foot of $580, also has a lower
energy and emissions intensity than recycling or groundwater desalination for both LADWP and
IEUA.4 Recycling, estimated as having a lower $/AF cost than groundwater desalination, also
has a slightly lower energy and emissions intensity. Such analyses could provide more accurate
accounting of the full costs, capital, operating, energy, and emissions of the options water
agencies consider. This is the type of full-accounting cost-benefit analysis that California’s
environmental policies are increasingly requiring.
4
With the caveat that the water used for groundwater storage is not transported over a long distance.
243
In addition, as illustrated in the previous section, to ensure this type of integrated
analysis, the State could consider requiring UWMP’s to incorporate the energy and emissions
intensity of their water supply sources and indicate the savings in energy and emissions of their
proposed water supply initiatives. In this way, the State would have a basis to monitor and
coordinate its energy, water and climate action plans and strategies across the various state
agencies.
Findings
Innovative Methodology Applied to Two Case Studies to Assess Energy and Emissions
Intensity of Water Sources. Life cycle assessment and spatial analysis were combined to assess
the amount and intensity of energy used by different water sources and their associated
greenhouse gas emissions in two water agencies studied, LADWP and the Inland Empire Utility
Agency.
Multiple Water Sources, their Location, Energy Mix of Utilities, Emissions Data from Various
Sources were Incorporated in the Analysis. Water sources included imported water from the
State Water Project, LA Aqueduct, Colorado River Aqueduct, Groundwater, Recycled Water,
Surface Water and Groundwater Desalination. Energy mixes from the different utilities
providing energy to the water agencies were incorporated in the analysis. Emissions date from
the various energy sources were estimated based on a literature review. The analysis calculated
the energy needed for transportation/conveyance of water to its treatment location, the energy
required for treatment and the energy required to deliver water from the treatment location to
customers.
Southern California Water Agencies Rely on Multiple, Geographically Diverse Sources
Requiring Varying Amounts of Energy for Transporting, Treating, and Delivering Water to
Customers. Securing a reliable supply of water for Southern California requires reliance on a
number of geographically diverse sources. Transporting, treating and distributing the water
requires varying amounts of energy inputs depending on the source. This relationship between
water imports and energy intensity, however, is not simple. While importing water via the
Colorado River and California Aqueducts is quite energy intensive, for instance, importing via
the Los Angeles Aqueduct requires no net input of energy since the aqueduct is entirely gravity
fed. Similarly, different treatment plants consume different amounts of energy to treat a given
volume of water. This is largely dependent upon the specific treatment technology utilized at
each plant.
244
For LADWP, the Most Energy Inefficient Source is the State Water Project East, the Most
Energy Efficient are the Los Angeles Aqueduct and Groundwater. Looking at LADWP
specifically, the most energy inefficient source, measured in kWh/AF, as well as the source with
the highest GHG emissions was the State Water Project East. The least energy intensive sources
of water are the LAA and groundwater on a per acre foot basis. Thus, water purchased from
MWD that is sourced from the SWP and CRA are the most energy intensive.
For IEUA, as well, imported water from MWD is the most energy intensive. For IEUA,
imported water from MWD sourced from the SWP and CRA are the most energy intensive as
well, although these imports represent a smaller percentage of total water supplies. The most
energy efficient sources of water for IEUA are surface and groundwater.
Energy Costs of Transporting Water from the Source to the Local Water Treatment Plant is
the Major Determinant of Energy Intensity for Agencies Studied. As utilities in Southern
California try to meet future demand, they should consider the energy it takes to convey the
water from its generation source to the water treatment plant, since this is the major determinant
of energy use and GHG emissions.
Incorporating Energy Intensity and Emissions Intensity of Water Sources in UWMPs can
Begin to Integrate State Environmental Goals. Including such an analysis in UWMPs can
ensure that water agencies take into account the energy intensity and greenhouse gas emissions
of their water supply decisions, and provide a basis for the State to begin to coordinate its
energy, water and climate action plans and strategies. As water agencies consider new water
supply options, such as water recycling, storm water capture, or desalination to augment their
own sources of supply, this type of analysis will provide a fine-grain accounting of the energy
and emissions cost or savings of the options they consider.
245
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Appendix 1: Map of LADWP’s water Infrastructure
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Appendix 2: Map of IEUA’s water infrastructure
250
Appendix 3: Map of water sources by energy intensity
251