Energy System Research and Testing Conversion Activities at NREL

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Energy System Research and Testing (Conversion)
Activities at NREL

• Gerry Nix
• March 20, 2003

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Goal Reduce Cost of Geothermal Electricity by
at Least 1/kWh

• Make the Plant Less Costly Reduce Investment
• Make the Plant Perform Better Higher
  Efficiency, Greater Output
• Make the Plant More Robust Harder to Break
• Make the Plant Easier to Operate Reduce Costs
  via Automation and Instrumentation
• Make the Plant Easier to Maintain Better
  Materials and Designs

Time Frame is in the Next 5 to 7 years for
Implementation
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Cost Reduction Targets

• Binary Plants Better Cycles (NREL, INEEL)
• Enhanced Heat Transfer (NREL, INEEL)
• Better Materials (NREL, BNL, INEEL)
• Innovative Components (NREL, INEEL)
• Better Instruments (INEEL, BNL)
• Additional Revenues (BNL, LLNL)

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Low-Temp Resources are More Common

• 83 of the sites require binary plants (also,
  EGS/HDR will most likely need binary plants)
• And 50 of the available energy is below
  temperatures requiring binary plants (170C)

Frequency of occurrence and energy of
hydrothermal convection systems identified by the
USGS in 1978
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Better Materials

• Polymer corrosion barrier coatings
• Prevent corrosion of geothermal plant equipment
• Reduce maintenance expenses

Steam vent at Cove Fort after 5 years of use
Approach is to use inexpensive coatings with
special properties on inexpensive base materials,
with performance equivalent to exotic alloys
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Extensive Field Testing
(Mammoth, Cove Fort, CalEnergy)
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Large Life Cycle Cost Savings
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Collaboration with Curran, Int.

• New Plant Built for PPS Business
• Perfected Electrostatic Application
• RD 100, FLC Awards

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Future Work

• Perform Long-Term Testing of Operating Equipment
• Evaluate at Temperatures to 350C
• Expand Number of Test Sites and Partners
• Test New, Thin Coating for Finned Tubing Exposed
  to Brine Spray

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Why Improve Heat Rejection?

• 90 of geothermal heat is rejected condensers
  make up 20-30 of plant cost
• Plant power will increase 1 for every1ºF drop
  in condenser outlet temperature
• Output of air-cooled plant can drop more than 50
  in summer, when electricity is highly valued
• Water cooling can greatly reduce reservoir
  pressure (The Geysers)
• Western states face water shortages air cooling
  most likely required for new plants, including
  EGS and HDR

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Air-Cooled Condenser Research Transpired and
Tabbed Fins

• Innovative designs
• Increase performance by 30
• CRADA with manufacturer (SRC)

Bottom line Improved heat transfer reduces heat
exchange area, and can reduce cost of electricity
by 0.5 cents/kWh
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Advanced Fins ITS Test Results
Latest tab fin shows about 40 more heat transfer
at the Same fan power with only 11 reduction in
air flow, plan is To fabricate prototype and test
at ITS
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Fin-on-Plate Air-Cooled Condenser
Test Setup
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Fin-on-Plate Condenser, 36 higher heat transfer
coefficient for the same pressure drop

• Potential Industry Partners for Manufacturing
  Linde, GEA Rainey, API Heat Transfer
• Carry out field testing in collaboration with
  Exergy
• Work with Experts in HX area (Prof. Ken Bell)
• Collaboration with HTRI

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Evaporative Enhancement of Air-Cooled Condensers
- Measurements at Mammoth
Munters increased net power output 62 (800 kW to
1,300 kW At 78F ambient
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Summary of Heat Rejection RD Benefits

• Increasing heat transfer on air and tube sides
  30 can reduce electricity cost by 0.5 /kWh
• Evaporative enhancement and trim condenser
  concepts can potentially double output of
  air-cooled plants on summer days payback for
  retrofit can be lt 3 years depending on water and
  electricity costs

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Innovative Components - Separators

• Separators disengage solids and liquids from
  vapor.
• They may also be used to separate NC gases.
• Poor performance results in costly damage to
  turbo-machinery.
• An industry-wide assessment of separators is
  needed to reduce OM costs.
• NREL brings advanced tools such as CFD
  (computational fluid dynamics) to industry
• Partnership with Two-Phase Engineering

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Well Test Plume Path lines
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Separator in Operation
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DIRECT USE - Applications Other Than Generating
Electricity at Temperatures Under 250F

• Heating and Cooling
• Aquaculture
• Industrial Process Heat
• Agricultural Process Heat
• Spas, Pools and Bathing

• Two Activities
• Direct Use Field Verification Projects
• Direct Use Technical Support, Testing and
  Evaluation, OIT and WSU

OIT web hits 2,000,000 , in-person or phone
assistance requests 2000
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Direct Use Projects
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Small Scale Field Verification Plants

• Kalina Cycle Plant to be built via Exergy to
  provide cost and performance data, support to
  DOE-GO
• Mixed Working Fluid Binary Plant Evaluation
  underway (Power Engineers) of a potential plant
  at Empire to provide cost and performance data
• DOE assumes a significant portion of the risk

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Geothermal Communications Objective -
Educate all stakeholder groups about geothermal
energy, and- Convey the mainstream potential of
this exciting technology
Geothermal Today all audiences
Quarterly GRC Bulletin Inserts industry
audience
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GPW State Posters
GPW Native American Poster
GPW State Fact Sheets GPW stakeholder audience
Web Sites
Exhibits and Displays
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NREL ESRT Summary

• It is Possible to Reduce COE by 1/kWh
• Opportunities Exist for Quick Returns, 5 to 7 yrs
  to Implementation
• Program is on the Way to Success, ala Direct
  Contact Condenser, PPS
• All Activities are in Partnership with Industry
• Proper Technical Areas are Targeted
• Cost-Effective RD Underway, guided by Extensive
  Systems Analyses
• Promoting Direct Use is Important