P-4 Geothermal Resource Assessment CM · geothermal technology, especially that using impervious...

851 S.W. Sixth Avenue, Suite 1100 Steve Crow 503-222-5161 Portland, Oregon 97204-1348 Executive Director 800-452-5161 www.nwcouncil.org Fax: 503-820-2370

W. Bill Booth Chair Idaho

Bruce A. Measure Vice-Chair Montana

James A. Yost Idaho

Tom Karier Washington

Dick Wallace Washington

Rhonda Whiting Montana

Melinda S. Eden

Oregon

Joan M. Dukes Oregon

February 26, 2009

MEMORANDUM TO: Power Committee FROM: Jeff King, Senior Resource Analyst SUBJECT: Assessment of geothermal generating resource potential Aggressive renewable portfolio standards and greenhouse gas control policies have increased the demand for sources of renewable or low-carbon energy. Geothermal energy, the crustal heat of the earth, is one such source. Conventional (hydrothermal) geothermal power generation relies on naturally-present water in near-surface porous heated rock as the heat transfer mechanism. The water is brought to the surface by means of wells and used directly or indirectly to drive a turbine-generator. The cooled geothermal fluid is then recycled to the underlying rock formation.

Geologic structures found in the Northwest thought to have potential for conventional geothermal electricity generation include the Basin and Range area of southeastern Oregon and southern Idaho, magma bodies underlying volcanic structures in the Cascade Range and certain locations in the Snake River Plain. Developable sites possessing the water, rock, and temperature qualities required for geothermal generation are rare, and geothermal exploration and development are expensive and financially risky ventures.

The 13 megawatt (net) Raft River project in southeastern Idaho, commissioned in January 2008, is the first commercial geothermal power plant in the Northwest. An expansion of Raft River is planned for 2009. Several additional Northwest projects have been announced in recent years, but only two of these appear to be under active development.

Incremental improvements to conventional technology and commercialization of advanced geothermal technology, especially that using impervious hot dry rock could greatly increase the availability of geothermal energy. The timeline for commercial development of advanced technology, however, is uncertain.

Staff will describe the potential availability, estimated cost of energy and issues associated with development of the geothermal resources. Presentation materials will be provided prior to the meeting.

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NorthwestPower andConservation

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Sixth Northwest Conservation & Electric Power Plan

GeothermalPower Generation Resource

AssessmentJeff King

Northwest Power and Conservation CouncilPower Committee

Boise, IDMarch 10, 2009


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Geothermal energy in the NorthwestNorthwest hydrothermal potential

At one time thought to be very large (thousands of MW)Lower expectations in recent years (hundreds of MW??)

Many attempts at development, few successfulLand use & visual conflicts, esp. in CascadesLow probability of locating natural hydrothermal resource (~ 20% success

rate)

First Northwest geothermal power plant in-service Jan 2008 Raft River Phase I - 13 MW net13 MW Phase II under contract; 13 MW Phase III proposed

Exploratory drilling reported at 5 additional sites1

Idaho - Willow SpringsOregon - Neal HS, OIT, Crump Geyser, Newberry

1) Geothermal Energy Association. U.S. Geothermal Power Production and Development Update. March 2009.

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Reported geothermal exploration

Newberry

Raft River

OITCrump Geyser

Neal HS

Willow Springs


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Binary-cycle geothermal plantNatural hydrothermal reservoir

• Temperature > 200oF• Permeable• Fluid (water) present• Feasible drilling depth (< 3km)

Hot geothermal fluid is extracted from reservoir via production wellsHeat is transferred to low boiling point working fluid in heat exchangerCooled geothermal fluid is re-injected to reservoirVaporized/pressurized working fluid drives turbine-generatorWorking fluid is condensed, returned to heat exchanger

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Reference plant: 40 MW binary-cycle3 x 13 MWnet units47 MW (gross); 39 MW (net) capacityClosed-loop binary cycle

Organic Rankine cycle (ORC) technologyNo release of CO2 or toxic materialsFull reinjection of geothermal fluid

Air or water-cooled condenser• Wet cooling - more efficient, more uniform seasonal output• Dry cooling in water-scarce areas

ModularWidely-used, mature technologyCan utilize moderate temperature resources

Raft River, ID - 13 MW


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Price year capital cost estimate

$0

$1,000

$2,000

$3,000

$4,000

$5,000

$6,000

$7,000

2003 2004 2005 2006 2007 2008 2009 2010

Vintage of Cost Estimate

Ove

rnig

ht c

apita

l cos

t (20

06$/

kW)

Generic EstimatesProjectsCERA PPCIProposed 6 Plan Draft

Proposed 2008 price year estimate $4200/kW

Declining to $3900/kW in 2009

Raft R.

Stillwater & Salt Wells

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Capital cost forecast

$0$500

$1,000$1,500$2,000$2,500$3,000$3,500$4,000$4,500

2005 2010 2015 2020 2025

Year of commercial service

Ove

rnig

ht c

apit

al c

ost

(200

6$/k

W)

Real costs decline to ~ 130% of 2006 values by 2013 (service yr)

2013 > Constant cost (no technical learning)

6th Plan Price Yr (2008) for 2010 service


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Hydrothermal power plant assumptions(2006 dollar values, 2008 price year)

Assm 90% annual CF95%Availability (%)

Power plant construction24 moFinal construction

2010 Earliest new PNW unit

Production drilling12 moEarly construction

Geologic assessment, permits & exploratory drilling

36 moPlanning

$4.50Variable O&M ($/MWh)

Incl. well field maintenance$175Fixed O&M ($/kW/yr)

Successful developmentw/ unsuccessful prospects ~ $5800

$4,200 +/- 25%Overnight capital ($/kW)

12% thermal efficiency28,500Heat Rate (Btu/kWh)

39Net capacity (MW)

Binary

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Hydrothermal geothermal costs ca. 2020

IOU financing

2020 service

90% CF

$0

$20

$40

$60

$80

$100

$120

Project-only,CurrentFederal

Incentives

Project-only,No FederalIncentives

IncludingUnsuccessful

Exploration, NoIncentives

Lev

eliz

ed li

fecy

cle

2006

$/M

Wh

CO2 (Proposed PRMmean value)Transmission &LossesSystem Integration

Variable Fuel

Variable O&M

Fixed Fuel

Fixed O&M

Capital


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Energy resource optionsEarly 2020s

$0

$50

$100

$150

$200

$250

$300

MT W

ind (L

ocal)

Gas Com

b Cycle

Conventional G

eoth

ermal

Columbia B

asin W

ind

Advanced N

uclear

AB Win

d > WA/O

R

ID W

ind (L

ocal)

Supercrit

ical P

C (WA/O

R)

IGCC (w

/o CSS)

Woody Bio

mass

MT W

ind > W

A/OR

NV CSP > S. ID

IGCC w

/CSS

NV CSP > W

A/OR

Utility

PV

Lev

eliz

ed c

ost

(200

6$/M

Wh)

Emission (CO2) costTransmission & LossesSystem IntegrationPlant costs

Transmission cost & losses to point of LSE wholesale deliveryNo federal investment or production tax creditsBaseload operation (CC, Nuc, SCPC 85%; IGCC, Bio - 80%)Medium NG and coal price forecast (Draft 6th Plan)Proposed Draft 6th Plan CO2 price.

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USGS assessment of resource potential

Identified geothermal systems are represented by black dots.


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Hydrothermal resource potential (MW)1

2044

47

1107

130

760

IdentifiedF5

1103

68

432

176

427

UndiscoveredF95

4836

300

1893

771

1872

Undiscovered Mean

790237WA

12751955266Totals

4991540163OR

20335915MT

493733381ID

UndiscoveredF5

Identified Mean

IdentifiedF95

1) U.S. Geological Survey. Assessment of Moderate and High-Temperature Geothermal Resources of the United States. 2008.

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Developable hydrothermal potential2008 USGS assessment is most current availableEstimate is akin to theoretical potential

• Excludes inaccessible federal land (e.g., National Parks)• Includes all other prospective resources

For planning purposes, developable potential:• Mean Identified Resource + Mean Unidentified resource• Low: 20% of F95 - 300 MW• Expected: 20% of Mean – 1200 MW (WGA near-term 1300 MW)• High: 20% of F5 - 3000 MW• MW = aMW in USGS report (assumed 100% capacity factor)

Historically slow rate of development may limit potential• e.g., 40 MW/yr over period of plan - 800 MW


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Conclusions: Hydrothermal geothermalNorthwest hydrothermal potential

Thought to be very large potential at one timeCascades volcanic resource less promising than previously thoughtRecent USGS assessment more optimistic for non-volcanic resources

First Northwest geothermal power plant in-service Jan 2008 Raft River Phase I, 13 MW net13 MW Phase II under contract; 13 MW Phase III proposed

Economics appear to be competitive w/ Columbia Basin wind and gas combined-cycle

Very high initial investment riskHigh up-front exploration cost (~10% of total plant cost)High dry (or cold) hole risk (80%)

Closed-cycle binary technology is becoming technology of choiceCan utilize moderate-temperature resources Negligible releases of CO2 or hazardous materialsBase load energy production w/sustained peaking capacity value

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Enhanced geothermal systems

USDOE, Geothermal Tomorrow 2008


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Subsurface temperature at 3.5 km depth1

1) 11,500 feet

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Subsurface temperature at 6.5 km depth1

1) 21,330 feet


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Areas of special EGS interestSnake R. Plain

Basin & Range

Oregon Cascades

MIT. The Future of Geothermal Energy. 2004

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USGS Provisional estimate of EGS potential

0

20,000

40,000

60,000

80,000

100,000

120,000

140,000

160,000

Identified F50 Undiscovered F50 EGS F50

Cap

acit

y (M

We)

WashingtonOregonMontanaIdaho

Current installed PNW capacity (57,000 MW)


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Needed for commercial EGS• Methods for increasing production well flow rates• Methods of characterizing the fractured volume• Methods of repairing short-circuits• Methods of understanding the role of existing faults in

augmenting or impeding flow• Robust instrumentation for hi-temp down-hole

environment • Methods of predicting scaling and deposition• Validation of long-term viability of commercial-scale EGS

at several sites

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Conclusions re: EGSEGS potential dwarfs that of other renewable resourcesEGS potential is widespread

Potentially far greater siting flexibility than other renewablesMore diffuse, may add to the cost and environmental impact of development

EGS remains commercially unprovenCommercial EGS is likely a decade or more in the future

Numerous issues need to be resolved through R&DCommercial demonstration projects will require several years to be up and runningSeveral years of operation likely to be needed to confirm the long-term viability of

EGS reservoirs

EGS costs likely to be higher than conventional geothermalDeeper wellsCost of establishing and maintaining fracture systemHot, high pressure environment


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Possible Sixth Plan action itemsEGS pilot projects at areas of special interest unique to the

Northwest• Snake River plain• Oregon Cascades

Participation in Basin & Range EGS pilot project

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