Geothermal Resources

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Geothermal Resources
Lisa Shevenell, Director
Dixie Valley, NV
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What is geothermal?

• Areas where energy can be tapped due to high heat
  flow in the near-surface part of the Earths
  crust (upper 5 km)
• Uses of geothermal various types of space
  heating, aquaculture, food dehydration,
  electricity production

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Why geothermal?

• Earth is losing heat continuously to space
• Thermal energy produced by decay of radioactive
  elements makes mantle hot, crust hot
• Geothermal areas result from high heat flow in
  upper part of crust where it can be utilized
• Normal geothermal gradient is 25?C/km
• Elevated geothermal gradient in some areas
• Magmatism, thin crust

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The Earth
Crust
Mantle
Outer core
Inner core
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Plate Tectonic Processes
Spreading Center
Continental Plate
Plate
Oceanic
Subducting
Convection
Plate tectonics provide a focusing mechanism for
heat loss
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Velocities cm/yr
Ring of Fire
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Plate Boundaries
Ring of Fire
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Geothermal Power Plants
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ANATOMY OF A GEOTHERMAL SYSTEM
GEOTHERMAL FEATURE
CONDUITS TO THE SURFACE
fractured rocks
GROUNDWATER RESERVOIR
HEAT SOURCE
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NEVADA IS UNDERGOING REGIONAL EXTENSION
EXTENSION DIRECTION
Warmer colors indicate greater dilational
(extensional) strain, as measured by movement
between permanent GPS stations located in the
Great Basin.
Dilational strain map of the Great Basin.
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IDEALIZED CROSS SECTION ACROSS THE BASIN AND
RANGE PROVINCE
Looking ENE
EXTENSION
EXTENSION
RANGE FRONT FAULT
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Formation of Extensional Geothermal Systems
CARTOON CROSS SECTION THROUGH BASIN AND RANGE
LOOKING ENE
Cold Groundwater
Cold Groundwater
Heated Groundwater
HOT ROCKS
RESERVOIR
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CASE 1 Geothermal water follows range front
fault to the surface
Upwelling geothermal fluids
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CASE 2 Geothermal water gets entrained in
surface groundwater
Upper SB
Lower SB
Upwelling geothermal fluids
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Effects of extensional tectonics in Nevada
Fault scarp from 1915 Pleasant Valley quake,
Nevada range front fault

• As the crust thins, hot rocks get closer to the
  surface, increasing heat flow
• Extension produces copious faulting and
  fracturing that serve as conduits for hot water
  to reach the surface

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Conventional Resource Size and Distribution

• Typically 50-200 MW per site
• Conventional development in Western US
• USGS 1978 estimate 150,000 MW (W US)
• USGS 2006-8 estimate pending
• Nevada near term 1700 MW likely 2500 MW
  available

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Size of Systems Aerial Resistivity 160 m
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Bradys-Desert Peak area color-shaded Interferogram
Period Nov 4, 95 to Sep 24, 00. Each color band
represents 1.6 mm range change over the
interferogram period. Production wells
magenta Injection wells blue Roads thin white
lines
I-80
Bradys
Desert Peak Field
noise
I-80
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2005 Projected New MW in 10 yr
376 MW currently permitted 50 MW already
installed
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Estimated Temperature at 6 km Depth
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Geothermal electricity generation- base load
First geothermal ? power plant Larderello,
Italy, 1904 Modern cooling tower, Larderello,
Italy, today ?
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Operation and Equipmentto be covered byDan
Schochet of Ormat
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Nevada geothermal power plants, thermal springs
and wells Power Plants at Nine Sites
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Production Well
Injection Well
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Nevada Flash Power Plants
Plant Year Output Temp (MW) (C) Beowaw
e 1985 16.7 199 Bradys 1992 21.1 186 Upper
SB 1988 14.4 236 Desert Peak 1985 9.9 205
Dixie Valley 1988 66 250
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Upper Steamboat Power Plant
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Nevada Binary Power Plants
Plant Year Output Temp Empire 1987 3.6 151
Soda Lake 1 1987 3.6 182 Soda Lake
2 1991 13 182 Steamboat (I,Ia) 1986 7.1 170
Steamboat (II,III) 1992 48 170 Stillwater 1
989 13 158 Wabuska 1 1984 0.6 107 Wabuska
2 1987 0.6 107
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Steamboat II, III (48 MW)
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Nevada Geothermal Graph
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New Plants

• Galena I (Richard Burdette) at Steamboat
• first Plant in gt13 years (end 2005)
• first Plant built after RPS passed
• produces 20 MW, net, to the grid
• Galena II 10 MW, 2007
• Others will double NV capacity in next 2-3 years

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New Plants in Progress

• Galena III 18 MW
• Salt Wells 10 MW
• Blue Mountain 25 MW
• Hot Sulphur 46 MW
• Jersey Valley 10 MW
• Brady 5 MW
• Desert Peak 5 MW
• Buffalo Valley 18 MW
• Kyle Hot Springs 10 MW
• Leach Hot Springs 18 MW
• Grass Valley 30 MW

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New Plants in Progress

• S. Big Smokey Valley 10 MW
• Surprise Valley 4.2 MW
• Fallon/Carson Lake 30 MW
• Carson Lake 5-10 MW
• Stillwater increase from 7 to 26 MW
• Pumpernickel Valley 5-10 MW
• Reese River 5-10 MW
• Fallon NAS 15-30 MW
• Rye Patch 12.5 MW
• Fireball Ridge 10 MW

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Other Known Areas - Current Work
Animas Valley (NM) Ormat Fish Lake
Valley California Energy Pyramid Lake Paiute
Tribe New York Canyon Terra Gen Hawthorne Navy H
azen Vulcan Power N. Salt Wells Vulcan
Power
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Worldwide Geothermal Direct Use

• Direct uses of geothermal water supply over
  11,000 thermal megawatts in over 40 countries
• Another 35 countries use natural hot springs for
  bathing but have not yet developed their
  geothermal reservoirs for commercial use.

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Space heating Beppu, Japan
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Balneology Walleys Hot Springs, Genoa
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Geothermal agriculture
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Alligators in Idaho!
Fish
Prawns
Farming uses fish, prawns, even alligators
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Direct use for district heating
Moana Warren and Manzanita Estates - and
Peppermill Casino
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• This is a "plate type" heat exchanger which
  passes hot geothermal water past many layers of
  metal plates, transferring the heat to other
  water passing through the other side of each
  plate.

• Principles of a heat exchanger
• Why not just use the hot water directly?

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States Currently Using Geothermal Resources (heat
pumps, direct use, heat, and power)

• Alabama
• Alaska
• Arizona
• Arkansas
• California
• Colorado
• Florida
• Georgia
• Hawaii
• Idaho
• Louisiana
• Mississippi
• Montana

• Nevada
• New Mexico
• New York
• North Carolina
• Oregon
• South Dakota
• Texas
• Utah
• Virginia
• Washington
• West Virginia
• Wyoming

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Nevada direct use geothermal facilities.
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Sustainability

• Meet the needs of the present generation w/o
  compromising needs of future generations (300 yr
  perspective)
• Dependent on initial quantity, rate of generation
  and consumption
• Duration of natural hydrothermal systems
• 5,000 1,000,000 yrs
• Age of waters often old (10,000 yrs in NV)
• Exploitation that exceeds natural recharge
  greatly reduces lifetimes
• Reinjection is key

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Sustainability

• The Geysers, CA
• Pressure Declines reduced power production
• Pipe treated waste water from Santa Rosa
• Dixie Valley, NV
• Pressure Declines
• Inject nearby shallower well water

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System Longevity

• Power Output
• Well Density
• Injection Strategy
• Initial Reservoir Pressure
• Initial Fluid Temperature
• Permeability

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Beneficial Environmental Impacts
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Freshwater Consumption
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Particulate Matter
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CO2 Emissions
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Deleterious Environmental Impacts
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Major Environmental Issues, Geothermal Development

• Visual impacts, noise, construction
• Cessation of spring discharge
• H2S pollution of atmosphere (routinely mitigated)
• Brine pollution of environment (routinely
  mitigated)
• Hydrothermal explosions induced boiling (rare)
• Reservoir drawdown, subsidence, interference,
  induced seismicity
• Landslides catastrophic and creeping

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Brine Chemistry (mg/kg)
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Dixie Valley, Recent Fractures
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2005 Seismic Activity at the Geysers

• Two quakes over 4.0 on May 8 and 9
• Three between 3.0 and 3.99
• Multiple quakes lt 3.0, often several per day

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Induced Seismicity SE Geysers
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Prevention and Mitigation

• Collection of pre-development background data
• Monitoring of important parameters during
  production (air, water,
• thermal activity, P/T declines, seismicity,
  subsidence, drawdown, etc.)
• Perseverance required

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2008 World Power Production

• United States 2,987 MW
• Philippines 1,970 MW
• Mexico 958 MW
• Indonesia 1172 MW
• Italy 811 MW
• Japan 535 MW
• New Zealand 635 MW
• Iceland 569 MW
• Costa Rica 163 MW
• El Salvador 204 MW

• Total for Asia 3,291 MW
• Total for EU members 1,124 MW
• Total geothermal power production 54.7 TWor 0.3
  of worlds electricity

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Capacity Factor(The ratio of the net electricity
generated, for the time considered, to the energy
that could have been generated at continuous
full-power operation during the same period. )

• Technology Capacity Factor
• Geothermal 97
• Biomass 80
• Wind 26 40
• Solar 22 32

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Competing in Energy Markets

• Power purchase agreements
• Renewable energy portfolio standards (RPS)
• Production tax credits
• Reduced risk in drilling needed
• Transmission lines
• Increased fossil fuel costs
• Climate change concerns

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Renewable Portfolio Standards (RPS)

• Nevada ( Renewables)
• 2003 8
• 2013 15
• 2015 20
• Geothermal could account for all of this based on
  current estimates
• (subject to suitable economic, regulatory and
  political conditions)
• National ( Renewables)
• 2008 1
• 2009 2
• 2010 3
• 2027 and thereafter 20

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