A Drop to Drink
The Economic Case Against Policy
Prohibition of CSP Wet Cooling
Ben Haley
Energy and Environmental Economics
101 Montgomery St., 16th Floor
San Francisco, CA 94104
Agenda
•
•
•
•
•
Concentrating solar power and water
CEC policy on water use for cooling
Analysis
Results
Conclusions
Source: N. Blair, Concentrating Solar Deployment Systems (CSDS) – A New Model for Estimating U.S.
Concentrating solar Power Market Potential
Source: EPRI, A Survey of Water Use and Sustainability in the United States with a Focus on Power Generation
Dry Cooling~80
gallons/MWh
Wet Cooling~800
gallons/MWh
County
Riverside
Riverside
San Bernardino
San Bernardino
Tulare
Tulare
CSP Capacity
State
Factor
CA
CA
CA
CA
CA
CA
0.25
0.43
0.25
0.43
0.25
0.43
2050
Capacity
15
15
15
15
1.3
1.3
Thousand
Thousand AcreAcre% of County
Feet/Year Wet Feet/Year Dry County Water Use if
Cooled
Cooled
Water Use Wet Cooled
81
138
81
138
7
12
8
13
8
14
<1
1
1,124
1,124
314
314
2,698
2,698
7%
12%
26%
44%
<1%
<1%
% of County
Water Use if
Dry Cooled
<1%
1%
3%
4%
<1%
<1%
Source: Congressional Research Service, Water Issues of Concentrating Solar Power (CSP) Electricity in the U.S.
Southwest
Why is cooling water so
important for CSP plants?
• Dry cooling towers have higher capital costs
and parasitic loads
• Hot, dry conditions (read: desert) mean a
large temperature difference between wet
and dry bulb temperatures, and thus higher
efficiency losses
• The most severe efficiency penalties occur
on hot days coincident with summer peak
loads
• More important for parabolic trough than
power tower
CEC Siting Policy in Action
• Beacon X
• Genesis X
• Abengoa 
CEC will approve wet cooling with potable resources if:
• No recycled water is available
• There are no negative environmental effects from usage
(significant groundwater overdraft, etc.)
• It can be proven that dry cooling makes the project
economically unsound
Policy Background
California Constitution (Article X, Section 2)
State Water Resources Control Board Resolution 75-58:
Water Quality Control Policy on the Use and Disposal of
Inland Waters Used for Power Plant Cooling
California Water Code 13050 and 13552.6
Warren-Alquist Act
2003 Integrated Energy Policy Report
NREL Solar Advisor Model
(SAM)
• Solar performance model
combined with a financial model
• Allows for inputs of various
system characteristics (field
size, turbine efficiency, etc.)
• Allows modeling of both wet and
dry cooling
SAM Simulation Results
Wet
Cooling
Dry
Cooling
Location
Capacity
Factor
LCOE
Incremental
Cost Penalty
Twenty Nine Palms AP
0.281
$0.1575
-
Incremental
Water Use
(AF/Y)
2151
Imperial AP
0.283
$0.1601
-
2117
Barstow-Daggett AP
0.262
$0.1684
-
2027
Chino AP
0.209
$0.2243
-
1657
Blythe-Riverside County AP
0.271
$0.1654
-
2069
March AFB
0.244
$0.1894
-
1886
Riverside Municipal AP
0.212
$0.2208
-
1682
Palm Springs International AP
0.257
$0.1742
-
1992
Twenty Nine Palms AP
0.281
$0.1674
6.3%
-
Imperial AP
0.283
$0.1738
8.6%
-
Barstow-Daggett AP
0.262
$0.1784
5.9%
-
Chino AP
0.209
$0.2399
7.0%
-
Blythe-Riverside County AP
0.271
$0.1779
7.6%
-
March AFB
0.244
$0.2041
7.8%
-
Riverside Municipal AP
0.212
$0.2357
6.7%
-
Palm Springs International AP
0.257
$0.1869
7.3%
-
Ex. Water Cost Simulation ResultTwenty Nine Palms Airport
$0.1720
$0.1700
$0.1680
LCOE
$0.1660
$0.1640
LCOE Dry Cooled
LCOE Wet Cooled
$0.1620
$0.1600
$0.1580
$0.1560
$0
$500
$1,000 $1,500 $2,000 $2,500 $3,000 $3,500 $4,000 $4,500
Annual Cost of Water Volume ($/AF)
Results
Location
Cost of Water Right
Twenty Nine Palms AP
$45,552
Imperial AP
$65,178
Barstow-Daggett AP
$45,628
Chino AP
$69,092
Blythe-Riverside County AP
$57,506
March AFB
$67,331
Riverside Municipal AP
$66,294
Palm Springs International AP
$57,738
Cost of Committed Water Volume Annual Cost of Water Volume
$1,518
$2,972
$2,173
$4,191
$1,521
$2,972
$2,303
$4,514
$1,917
$3,762
$2,244
$4,383
$2,210
$4,328
$1,925
$3,757
Water Transfers
• 155 water transactions examined (20002009) from Water Transfer Database.
Values recorded in terms of “committed
water volume.”
• Not a hugely active market
• Compares short term and long-term
transfers on an equal basis
• Uses “average committed water volume” as
a proxy for “anticipated firm committed
water volume”
$2,500
Water Transfers: Cost of
Committed Water Volume
(2000-2009)
$2,000
$1,500
Maximum
$/AF
Weighted Mean
CSP Plants
$1,000
$500
$0
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
Sources:
Pacific Institute, Waste Not Want Not
Congressional Research Service, Water Issues of Concentrating Solar Power (CSP) Electricity in the
U.S. Southwest
Conclusions
• All potential CSP plants demonstrate a higher value
for water than do other users, according to recent
market transactions.
• The existence of potential water conservation is not
reason enough to mandate it; hindering
development of CSP projects is an uneconomic
water conservation strategy.
• Using potable water resources for cooling should
continue to be assessed on a case-by-case basis.
• The state’s water policies, or lack thereof, make
cooling water use an added uncertainty for
developers.