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CSP and the Energy Water Nexus – Greg Bartlett

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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

HUALAPAI VALLEY SOLARWho we are

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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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Parabolic troughs

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Aerial view of HVS Project

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HVS power block

Aerial photo of the Hilltop WWTP

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THE WATER CHALLENGEWhy we are here

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Abundant fuel

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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.

THE HVS APPROACHThe developer should site and design responsibly

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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)

EFFLUENTTreated wastewater is reclaimed water, ready to use again

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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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Class A+ allowed uses

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Class B+ allowed uses

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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

HVS AND EFFLUENTPlans to use reclaimed water to generate solar electricity

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The Vision

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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

HVS water sources – if online today

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SUMMARYCSP and the Energy Water Nexus

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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

greg@mohavesun.comSkype address: gjbartlett

Greg Bartlett