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City of San Diego’s Water and Energy Nexus
World Resources Simulation CenterSeptember 22, 2010
George J. Adrian, PEPublic Utilities Department Long-Range Planning & Water Resources Division
Sources of San Diego’s Water Supply
2
LAKESHASTA
LAKEOROVILLE
State Water Project(Bay-Delta) 30%
Colorado River 50%
Local Supplies and Conservation 20%
San Diego County imports ~80% of its
water supply
San Diego Water System
3
• 1.3 million people
• 404 Square Miles
• Avg. Daily Consumption more
than 200 MGD
• 9 Raw Water Reservoirs
• 3 Water Treatment Plants
• More than 3,000 Miles of
Pipelines
• 27 Distribution Reservoirs/Standpipes
• 50 Pump Stations
• More than 110 Pressure Zones
By 2030 San Diego may need 11% more water
2007: 248,000 acre-feet per year
2030: 275,925acre-feet per year
San Diego Keeps Growing
Local Surface Water3%
Recycled Water 3% Conservation
15%
Imported79%
Source: City of SD Public Utilities Department 8/16/10
FY 2010 Actuals
Water Supply Portfolio
Carbon Footprint by Water Source
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0
500
1000
1500
2000
2500
3000
3500
4000
4500
0
500
1000
1500
2000
2500
3000
3500
4000
4500
ColoradoRiverAqueduct
StateWaterProject
Groundwater RecycledWater
SeawaterDesal
BrackishGroundwaterDesal
OCWD Groundwater Replenishment Project
kWh
/AF
Source: Pacific Institute analysis regarding SDCWA data Source of OCWD GW Replenishment: City of San Diego
Adaptation: Local Water Supplies
• Water Conservation• Local Runoff - Reservoirs• Recycled Water• Brackish Groundwater Desalination• Groundwater Conjunctive Use• Seawater Desalination (San Diego Region)• On-site alternatives:
– Graywater– Stormwater capture
7
Electricity Demand in State of California19% of electricity in California is water related
8Refining Estimates of Water Related Energy Use In California, CEC, December 2006
3% 5%3%
3%4%
1%
81%Gigawatt Hours (GWH)
Agricultural
Residential
Commercial
Industrial
Water Supply and Treatment
Wastewater Treatment
Balance
Estimated Energy Intensity of Water in San Diego County
• Relationship of water to energy, broken down
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56%8%
1%5%
30%END USE
WASTEWATERTREATMENT
WATERTREATMENT
DISTRIBUTION
SOURCES ANDCONVEYANCE
Energy Down the Drain, NRDC, August 2004
Refining Estimates of Water Related Energy Use In California
Indoor uses Outdoor usesNorthern California
Southern California
Northern California
Southern California
kWh/MG kWh/MG kWh/MG kWh/MGWater Supply & Conveyance 2,117 9,727 2,117 9,727
Water Treatment 111 111 111 111Water Distribution 1,272 1,272 1,272 1,272Wastewater Treatment 1,911 1,911 0 0
Regional Total 5,411 13,022 3,500 11,111
10CEC, December 2006
Residential water energy useResidential Water Use
% Water Use
Energy for Heating (kWh/AF)
Energy in Distribution, Treatment, wastewater treatment, and Conveyance , (kWh/AF)
Energy Use Total (kWh/AF)
% Water-Energy Use
Toilet 24 0 3,239 3,239 5
Dishwasher 2 36,867 3,239 40,106 5
ClothsWasher 14 36,867 3,239 40,106 34
Shower 21 36,867 3,239 40,106 51
Landscape 40 0 2,424 2,424 5
% Annual Water-Energy Use
100% 82% 12% 100% 100%
11The interaction of water and energy In California, Lawrence Berkeley National Laboratory, June 12, 2008
Interaction of Water and Energy
12The interaction of water and energy In California, Lawrence Berkeley National Laboratory, June 12, 2008
Desalinization
Shasta (storage)
Visualizing Sustainability• Acceptable Uses for Water
– Establishing priorities• Residential • Agricultural• Business
– tourism• Recreation
• Change in User Behavior Patterns– Adjust expectations for uses and quantity of
water to correspond to priorities– Provide feedback, show visual link to water use
and economic health13
Challenges to the City• Efficient /effective use of water
– Indirect Potable Reuse (IPR)
– Recycled water
– Stormwater Rainwater harvesting
– Graywater
• Changing public perception of water, its value and real cost
• Using less water or using the water you have more efficiently – Conservation– Alternative landscaping
• Edible gardens…..minimal lawns14
What’s at Stake?• Water shortages or rationing
• Creation of unsustainable systems, leading to water and other shortages for future generations.
• Quality of life
– Economy?
– Food diversity and security?
• Energy brownouts.
15
Possible Breakthrough’s
16
• Sustainable systems and the relationship between water and energy and earth systems (greenhouse gases)– Multiple (hence efficient) use of water
for our needs• Recycled water
– Advanced treated water• Graywater use
– Recovery of water (hence energy) for other uses.
• Rainwater capture• Re-landscape (contours to capture water) -
Stormwater diversions– Retail market that primarily supports
water efficient plants
San Diego is Conserving
18
1970
1972
1974
1976
1978
1980
1982
1984
1986
1988
1990
1992
1994
1996
1998
2000
2002
2004
2006
2008
0
50000
100000
150000
200000
250000
300000
0
200
400
600
800
1000
1200
1400
1600
Demand (AF)
Population
Fiscal Year
Pop
ula
tion
x
10
00
Reduced Water Demand
Wate
r D
em
an
d in
Acre
-fe
et
