Pythagoras Solar LLC Investor Presentation

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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

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HUALAPAI VALLEY SOLAR

• Who 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
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Aerial photo of the Hilltop WWTP
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THE WATER CHALLENGE

• Why 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 (waterair)
• 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 Water Usage (total) Annual Water Usage (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

• 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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THE HVS APPROACH

• The 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)

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EFFLUENT

• Treated 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

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HVS AND EFFLUENT

• Plans 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 Projects 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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HVS water sources if online today
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SUMMARY

• CSP 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
Greg Bartlett
Project Director Mohave Sun Power LLC 85 Hamilton
Street Cambridge, MA 02139 1 206 349 6068
mobile greg_at_mohavesun.com Skype address
gjbartlett
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