1 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

The Parker Ranch installation in Hawaii

Geothermal Technologies Program (GTP)

DOE Updated U.S. Geothermal

Supply Curve

Chad Augustine

National Renewable Energy Laboratory

Strategic Energy Analysis Center

Chad.Augustine@nrel.gov February 1, 2010

Chad Augustine (NREL)

Katherine R. Young (NREL)

Arlene Anderson (DOE-GTP)

NREL/PR-6A2-47527

Pacific Gas & Electric/PIX 00059

NREL is a national laboratory of the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, operated by the Alliance for Sustainable Energy, LLC.
2 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

U.S. Geothermal Supply Curve Project

Purpose: To provide input to annual reporting by the U.S. DOE under the 

Government Performance and Results Act of 1993, the DOE portfolio development 

support processes, and market penetration models in support of other DOE analyses.

Outline

Geothermal Resource

• Hydrothermal resource

– Identified

– Undiscovered

• Enhanced Geothermal Systems (EGS) resource

– Near-Hydrothermal Field EGS

– Deep EGS

Supply Curve

• Based on expert input

• Two cases: Base and target

Results, Conclusions, and Recommendations
3 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

General Approach

Slide 3

Risk 

Assessment

• Expert input 

• Present and 

future costs 

• Different budget 

scenarios

Estimate 

LCOE in 

GETEM

• Resource 

characteristics

• Component 

costs

• Time/budget 

scenario

Supply 

Curve

Input for 

Market 

Penetration 

Models

• NEMS

• MARKAL

• ReEDS

• SEDS

Geothermal 

Resource • Define resource

• Identify 

information 

sources

• Develop database

Cases • GTP R&D goals

• Budget levels

• Time frames

• Reference 

scenarios

GIS Data 

Mapping

• Spatial 

coordinates 

of resources
4 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

GEOTHERMAL TECHNOLOGIES

Hydrothermal

• Conventional technology – Steam, dual flash, flash, binary

• Shallow (1-3 km), hot (150+ oC), naturally occurring, localized

• Examples – The Geysers, Salton Sea, Hatch (NV) Plant

Enhanced Geothermal Systems (EGS)

• Near-Hydrothermal Field EGS

• “Almost” hydrothermal fields – lack permeability and/or in-situ fluids

• Near-term, lowest cost EGS – likely to be developed first

• Examples –Geysers (Calpine), Newberry (AltaRock), Raft River (U. Utah)

• Deep EGS

• Deployable “anywhere” – drill until high temperatures found

• 3+ km deep, no natural permeability and/or in-situ fluid – fracture + flow

• Long term, higher costs – likely to follow successful near-field tests

• Examples – Fenton Hills, Soultz, Cooper Basin

Oil and Gas Co-Produced Fluids Direct Use

Geopressure Fluid Ground Source Heat Pumps
5 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Resource Characterization

Hydrothermal Resource: Identified

Installed Capacity

• Geothermal Energy Association: 

3,153 MWe (Sept. 2009)

• Energy Information Administration: 

2,480 MWe (summer capacity, 12/31/07)

Potential Capacity

• USGS Circular 790 (1979): 

23,000 ± 3,400 MWe

• USGS 2008 Geothermal Resource 

Assessment:

• Mean: 9,057 MWe

• 95%ile: 3,675 MWe

• 5%ile: 16,457 MWe

For NREL study...

6,394 MWe remaining capacity

Source: Williams et al. (2008), USGS, “Assessment of Moderate- and High-Temperature Geothermal Resources of the United States” http:/pubs.usgs.gov/2008/3082
6 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

Hydrothermal Resource: Undiscovered 

USGS 2008 Geothermal Assessment

• Based on GIS mapping tools and 

statistical model of spatial correlation 

of geological factors

• Estimated undiscovered hydrothermal 

resource potential:

• Mean: 30,030 MWe

• 95%ile: 7,917 MWe

• 5%ile: 73,286 MWe

For NREL Study...

30,030 MWe potential capacity
7 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

Near-Hydrothermal Field EGS

Source: Williams et al. (2008), USGS, “Assessment of Moderate- and High-Temperature Geothermal Resources of the United States” http:/pubs.usgs.gov/2008/3082

Near-hydrothermal field EGS resource 

is “halo” around hydrothermal fields.

Formal assessment not performed yet

• Use current identified hydrothermal sites

• Assume resource is difference between 

USGS hydrothermal high (5% probability) 

and mean values for each site represents 

near-hydrothermal field EGS opportunity

For NREL Study...

7,031 MWe potential capacity

Caveats

• First-order estimate of resource

• Does not consider near-hydrothermal field 

EGS resource associated with 

undiscovered hydrothermal sites
8 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

Previous Assessments

• MIT “Future of Geothermal Energy” 

report (2006) concluded 100 GWe of 

EGS capacity by 2050 possible with 

reasonable R&D investment 

• USGS 2008 Geothermal Resource 

Assessment estimated mean value 

of 517,800 MWe deep EGS potential

• Limited to 11 Western states

• Only considers 3-6 km depth 

range

• Federally-protected and DOD 

lands excluded

Deep EGS Resource
9 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

• Same method used in MIT report (2006)

• Thermal resource based on SMU maps 

of temp vs. depth (3-10 km) used in 

previous assessment

• Exclude federally-protected lands (e.g. 

DOD, federal parks)

• Potential electric capacity calculation 

methodology:

• Calculate heat in place for 1-km thick 

slices of rock

• Apply recovery factor (20%), heat recovery 

rate (30 years), and assumed plant 

efficiency (DiPippo 2004) for resource 

temperature

• Multiply potential electric capacity of each 

resource temperature range by area 

covered on map

For NREL Study...

15,908 GWe potential capacity

Resource 

Temp 

Range

Average 

Reservoir 

Temp 

Decline

Recovery 

Factor Plant Life Recoverable Heat Rate

Plant 

Efficiency

Potential 

Electric 

Capacity

(

o

C) (

o

C) % (years) (MW/km3) % (MW/km3)

T Tdecline Rg life Qth,dot ηth We

150-200 10 20% 30 5.39 11% 0.593

200-250 10 20% 30 5.39 14% 0.755

250-300 10 20% 30 5.39 16% 0.863

300-350 10 20% 30 5.39 18% 0.970

>350 10 20% 30 5.39 22% 1.186

Deep EGS Resource - NREL
10 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

Deep EGS Resource - NREL

Excluded areas: DOD land, federally-protected land (e.g. - Yellowstone)

Potential Electric Capacity (MWe)

Resource Temperature (oC)

150-200 200-250 250-300 300-350 350+

Reservoir Depth (km)

4 91,516 117 0 0

5 590,763 26,526 134 0 0

6 1,139,749 227,969 7,680 50 0

7 1,337,049 723,692 86,057 631 0

8 1,539,597 1,129,434 345,285 32,964 320

9 1,881,116 1,159,750 761,653 138,204 9,922

10 1,907,066 1,251,474 1,015,937 433,749 69,298
11 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource

Results – NREL study

*Technologies such as co-produced fluids, geopressured not assessed

Resource Resource Potential Capacity

Capacity 

(GWe) Source(s) and Description

Hydrothermal

Identified 

Hydrothermal 

Sites

6.39

USGS 2008 Geothermal Resource Assessment1

- Identified hydrothermal sites

- Sites ≥110 oC included

- Currently installed capacity excluded

Undiscovered 

Hydrothermal 30.03 USGS 2008 Geothermal Resource Assessment1

Enhanced 

Geothermal 

Systems 

(EGS)

NearHydrothermal 

Field EGS

7.03

Assumptions based on USGS 2008 assessment1

- Regions near identified hydrothermal sites

- Sites ≥110 oC included

- Difference between mean and 95th%ile hydrothermal 

resource estimate

Deep EGS 15,908

NREL 2006 Assessment2, MIT Report3, SMU Data4

- Based on volume method of thermal energy in rock 

3-10 km depth and ≥150 oC

- Did not consider economic or technical feasibility

1 (Williams, Reed et al. 2008b)

2 (Petty and Porro 2007)

3 (Tester et al. 2006)

4 (SMU 2009)
12 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

General Approach

Risk 

Assessment

• Expert input 

• Present and 

future costs 

• Different budget 

scenarios

Estimate 

LCOE in 

GETEM

• Resource 

characteristics

• Component 

costs

• Time/budget 

scenario

Supply 

Curve

Input for 

Market 

Penetration 

Models

• NEMS

• MARKAL

• ReEDS

• SEDS

Resource 

Characterization

• Define resource

• Identify 

information 

sources

• Develop database

Cases • GTP R&D goals

• Budget levels

• Time frames

• Reference 

scenarios

GIS Data 

Mapping

• Spatial 

coordinates 

of resources
13 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Estimate LCOE in GETEM

Enabling Technology Base Case 

Value

Target Case

Value

Production Well Flow Rate 30 kg/s 60 kg/s

Thermal Drawdown Rate 3.0 %/year 0.3 %/year

Production/Injection Well Ratio 2:1 2:1

Technology Component Cost and Performance Data

• Apply expert input distributions from 2009 risk assessment to GETEM

• Use @Risk risk analysis software to run Monte Carlo simulations

• Drilling Costs updated to value 30% lower than 2008 BLS PPI index value based on 

conversations with leading geothermal drilling contractors

Hydrothermal

• Estimate LCOE for each identified site using GETEM

• Undiscovered hydrothermal resource characteristics based on average of existing 

identified hydrothermal sites in each state

EGS

• Estimate LCOE for each temperature/depth combination using GETEM

• Two cases considered:
14 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Hydrothermal Supply Curve

(Identified & Undiscovered)

0

10

20

30

40

50

60

70

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000

Levelized Cost of Electricity (cents/kWh)

Cumulative Capacity (MWe)

Identified Hydrothermal 

Sites

Undiscovered 

Hydrothermal Resource

Grey lines show 10th%ile and 90th%ile values for supply curve.
15 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Near-Hydrothermal EGS Supply Curve

0

20

40

60

80

100

120

0 1,000 2,000 3,000 4,000 5,000 6,000 7,000 8,000

Levelized Cost of Electricity (cents/kWh)

Cumulative Capacity (MWe)

BASE CASE

TARGET CASE

• Base Case: 3%/year thermal drawdown rate, 30 kg/s producer well flow rate

• Target Case: 0.3%/year thermal drawdown rate, 60 kg/s producer well flow rate

• Grey lines show 10th%ile and 90th%ile values for supply curve.
16 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Deep EGS Supply Curve

• Base Case: 3%/year thermal drawdown rate, 30 kg/s producer well flow rate

• Target Case: 0.3%/year thermal drawdown rate, 60 kg/s producer well flow rate

• Grey lines show 10th%ile and 90th%ile values for supply curve.

0

10

20

30

40

50

60

70

80

90

100

1 10 100 1,000 10,000 100,000 1,000,000

Levelized Electricity Cost (cents/kWh)

Cumulative Capacity (MWe)

BASE CASE

TARGET CASE
17 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Aggregated Supply Curve

• Base Case: 3%/year thermal drawdown rate, 30 kg/s producer well flow rate

• Target Case: 0.3%/year thermal drawdown rate, 60 kg/s producer well flow rate

0

5

10

15

20

25

30

35

40

0 5,000 10,000 15,000 20,000 25,000 30,000 35,000 40,000 45,000 50,000

Levelized Cost of Electricity (cents/kWh)

Cumulative Capacity (MWe)

Deep EGS

Undiscovered Hydrothermal

Near-Hydrothermal Field EGS

Identified Hydrothermal

BASE CASE

TARGET CASE
18 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

0 10 20 30 40 50

LCOE (¢/kWh)

LCOE for Reservoir 

Depth-Temperature

0 10 20 30 40 50

LCOE (¢/kWh)

150 200 250 300 350 400

Reservoir Temperature (oC)

Temperature Profile

150 200 250 300 350 400

Reservoir Temperature (oC)

0

1

2

3

4

5

6

7

8

9

10

0

1

2

3

4

5

6

7

8

9

10

Reservoir 

Depth (km)

Power

Plant

Optimum

Depth Minimum

LCOE

Deep EGS: Optimum Reservoir 

Temperature-Depth
19 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Updated U.S. Geothermal Supply Curve
20 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Geothermal Resource and Supply Curve 

1. 36.4 GW undeveloped hydrothermal available (majority undiscovered)

2. Near-hydrothermal field EGS resource has potential to be low-cost method 

of expanding capacity around existing fields

3. Deep EGS is huge resource, but deployment controlled by economics

4. Meeting GTP reservoir engineering goals (target case) could significantly 

lower EGS costs and deployment levels

Caveats and Limitations

1. Results dependent on assumptions in base/target cases

2. Supply curve results assumed relatively high drilling costs compared to 

current drilling cost trends

3. Geothermal similar to oil & gas – as exploration and recovery techniques 

improve, amount of recoverable reserves should increase

More Resource Assessment Needed 

1. Undiscovered hydrothermal and near-hydrothermal field EGS need more 

thorough assessment

2. Deep EGS – better resolution data need for temperature vs. depth maps

3. Co-produced fluids assessment needed

Conclusions/Recommendations
21 | 2009 DOE GEOTHERMAL SUPPLY CURVE UPDATE: Prepared by the National Renewable Energy Laboratory (NREL) eere.energy.gov

Thank You

Chad Augustine

National Renewable Energy Laboratory 

1617 Cole Blvd.

Golden, CO, 80401-3305, United States

e-mail: Chad.Augustine@nrel.gov

Katherine R. Young

National Renewable Energy Laboratory 

1617 Cole Blvd.

Golden, CO, 80401-3305, United States

e-mail: Katherine.Young@nrel.gov

Arlene Anderson

U.S. Department of Energy (DOE)

Office of Energy Efficiency and Renewable Energy (EERE)

Geothermal Technologies Program (GTP) 

1000 Independence Ave SW

Washington, DC, 20585, United States

e-mail: Arlene.Anderson@ee.doe.gov