1 csp and the energy water nexus – greg bartlett
TRANSCRIPT
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Summary
Solar thermal plants need to be sited properly Is there adequate groundwater? Can a previous/planned usage be “retired? Is reclaimed water available?
Case Study: Hualapai Valley Solar Project Yes – more than 15 million AF in remote sub-basin Yes – approved 100-year residential usage Yes – reclaimed water from City of Kingman Result – net reduction in groundwater impact
Improperly sited projects are not viable projects
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Hualapai Valley Solar Project
340 MW parabolic trough project (solar thermal)
7+ hours of thermal energy storage
Private land near Kingman AZ (4,000+ acres)
State of the art evaporative cooling system
Two sources of cooling water Groundwater Effluent water from City WWTP
Start of operation: 2014
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Solar technologies
Solar Trough is best for utility scale Proven, reliable steam turbine Thermal energy storage used to match load Financeable and operating today at scale
Solar Tower, Solar Chimney, CPV, Stirling Not yet financeable or operating at scale
PV Violent intermittency Regional grid and utilities cannot support scale
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Alternatives to Water Cooling
Air Cooling Large towers, large fans, large electricity usage Higher capital cost: 2-3x Efficiency drops significantly on hot days: up to 40% LCOE: +7-9%
Hybrid Cooling Highest cost, to build both systems (water+air) Switch between both, based on air temperature Solar plants generate mostly on hot days, thus a strong
operational bias against air cooling
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Market realities today
Why are there no Air / Hybrid Cooling solar thermal plants in the world today? Not competitive – solar is already at a premium; the 7-
9% additional LCOE would be passed on to utility ratepayers
Air (and thus Hybrid) Cooling are not cost effective, except for 24/7 power plants
Thus, banks see these alternatives as unacceptable risks…
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Policy considerations
Today, Water Cooling is needed The only economical solution today to meet RPS
Need to build some solar thermal plants now
Solar plants should be sited to: …avoid endangered aquifers …retire previous/planned water use …allow use of reclaimed water
Siting is the single most overlooked and most important criterion; not all projects are viable.
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Policy should cover all uses
Water User Annual WaterUsage (total)
Annual WaterUsage (per acre)
Family of 5 on 1/4 acre 1 AF 4.0 AF
18-Hole Public Golf Course 600 AF 5.0 AF
Hualapai Valley Solar 2,400 AF 0.6 AF (1)
Spring Hill Gas Power Plant 4,000 AF 40.0 AF (2)
Copper Mine 5,500 AF 1.6 AF
Catalyst Paper Mill 11,862 AF 118.6 AF (2)
Alfalfa Farm 26,400 AF 5.5 AF
Navajo Coal Power Plant 27,200 AF 15.5
(1) ADWR issued a 100-Year Letter of Adequacy to a planned residential development that included portions of the HVS site for 1.2 AF per acre per year.
(2) Actual acreage not known, estimated for comparison purposes to be 100 acres.
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Reuse and reduce usage
Reuse – plans to use reclaimed water Reduce – evaluating other technologies and
techniques to reduce net water usage Electrocoagulation Centrifugal filtration Recycling, capture of rainwater, etc.
This strategy meets the goals of the Arizona Blue Ribbon Panel on Water Use (Dept. of Water Resources, Dept. of Environmental Quality, Corporation Commission)
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What is effluent?
Wastewater that is treated & suitable for reuse
Arizona classes of reclaimed water: Class B+ reclaimed water – wastewater that has
undergone secondary treatment, nitrogen removal treatment, and disinfection
Class A+ reclaimed water – additional filtration
More than 190,000 AF of effluent is being generated annually in Arizona
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Effluent users in Arizona
Palo Verde Nuclear Power Plant
SCA Tissues
Arizona Snowbowl Ski Resort (proposed)
Various golf courses Many counties require new courses to use effluent
City of Flagstaff 2,300 AFY of effluent in use by 10 schools, 8 parks,
2 cemeteries, 3 golf courses and a playing field at NAU
Effluent cooling advantages
Relatively constant water quality Groundwater quality can change over time
Preserves water currently stored in aquifer
Reuses an otherwise wasted resource
Wastewater may be easier to treat
Consistent with AZ Blue Ribbon Panel
Palo Verde Plant – operational precedent
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Effluent cooling challenges
Higher capital & operating costs
Supply does not match demand Supply is relatively constant year-round, while demand
for cooling water is greatest in summer Requires storage to buffer flows
Pipeline ROW/easements required for length of pipe Expands the Project’s environmental footprint
Potential risk of contaminating cooling water
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City of Kingman
Upgrading existing Hilltop WWTP (2011)
Treats more than 1.4 MGD today
Designed to expand to 5 MGD All new growth will be processed at Hilltop North Kingman (10,000 homes) currently using septic
Today, the effluent is evaporating in ponds
No effluent purchaser prior to HVS
Located 22 miles due south of HVS site
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Chronology
Letter of Intent with Kingman – Jun 09
Binding MOU – Dec 09
New City Policy on Sale of Effluent Approved by Kingman City Council – Mar 10
First draft of Purchase Agreement – Jun 10
Currently negotiating final purchase contract
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Options considered
Pipeline – construct a pipeline, pumping stations, and storage facilities at and/or between WWTP and HVS site
Recharge – inject effluent into the aquifer near WWTP, and withdraw using groundwater wells at HVS site
Contracted Delivery – contract with a third party to deliver effluent to the HVS site, allowing delivery of effluent to other users
Trade – deliver effluent to other user(s), thus permitting them to decrease their demand on the Kingman sub-basin, and withdraw using groundwater wells at HVS site
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Summary
Solar thermal plants need to be sited properly Is there adequate groundwater? Can a previous/planned usage be “retired? Is reclaimed water available?
Case Study: Hualapai Valley Solar Project Yes – more than 15 million AF in remote sub-basin Yes – approved 100-year residential usage Yes – reclaimed water from City of Kingman Result – net reduction in groundwater impact
Improperly sited projects are not viable projects
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Contact InformationHualapai Valley Solar Project
Project DirectorMohave Sun Power LLC
85 Hamilton StreetCambridge, MA 02139
+1 206 349 6068 mobile
[email protected] address: gjbartlett
Greg Bartlett