Cost and Supply of Geothermal Power

Susan PettyBlack Mountain Technology

The Geothermal Resource Base

USGS Circular 790Released in 1979Based on data from 1950’s-1978

Bonneville Power Authority Pacific Northwest onlyMore detail for Northwest resources

State Geothermal Resource MapsAll states with geothermal resourcesMaps don’t evaluate resource potential

US Geothermal Resource Estimates

USGS Circular 790Estimates recoverable heat and potential power outputIdentifies resources on basis of surface manifestations23,000 MWe from identified hydrothermal resourcesNo assumptions about cost to produce powerEnhancing permeability of identified resources a possibilityDoes not include hot dry rockCuts off electric power generation at 150°C

US Geothermal Resource Estimates

BPA Northwest Resource Evaluation More detailed estimates for Washington, Oregon, Idaho and MontanaAdds ~3500 MWe to USGS estimates for areaDoes not rely solely on presence of hot springs Considers cost in ranking resources for development

Other Geothermal Resource Data

State geothermal resource mapsCurrently being updated by INL and some state geological surveys or universitiesIncludes areas of high heat flow, surface manifestations and wells

Geothermal Map of the USRecently updatedBased on heat flow calculated from shallow and deep well temperature measurementsData available on web

Thermal Springs Map of the USSprings with measured temperatures above regional groundwater temperature

USGS Updated Basin and Range Temperature Gradient DatabaseNow available on web from http://pubs.usgs.gov/of/1999/of99-425/webmaps/home.html. Includes data from industry exploration

State Geothermal Resources Map - Utah

Utah Geothermal Resource Map - INEL

Geothermal Map of North America

Detail of Utah

Temperatures at Depth for Continental US

Temperature at 6 km

With depth to bedrock

Resource From Heat Mining

Area in Utah that is above 240°C at 6 kmTotal heat in place converted to electricity - 136,000 MWe for 1000 yearsRecoverable heat at 20% recovery – 27,000 MWe

Thermal Spring Map - Western US

Thermal Spring Map - Utah

Great Basin

Geothermal

Gradient Map

Cost of Geothermal PowerSandia – Petty, et al, Impact of Technology on Cost of Geothermal PowerEPRI – Brugman, et al, Next Generation Geothermal Power Plants - 1996Renewable Northwest Project: Geothermal Power - 2002

Resource CapitalCost ($US1999/kW)

Geothermal $1,150–$3,000

Hydropower27 $735–$4,778

Coal28 $1,070–$1,410

Nuclear29 $1,500–$4,000

Modeling Cost of Geothermal Power

IM-GEO – Impact of Technology on Cost of Geothermal Power – Completed 1990, Updated – 1994

Used to build supply curves – 1992Input for NEMS modeling by EIAEIA currently using this study escalated to current $

GETEM – Geothermal Energy Technology Enhancement Model

In Beta testingBased on drilling costs from Sandia study 2004Plant capital costs from reports by Ormat and Power Engineers and on EPRI 1996 study.

Modeling Data Requirements

Resource DataTemperature DepthFlow per wellSize of resourceTemperature/Pressure decline rateDrilling difficulty – geologyExploration success rateConfirmation success rate

Plant DataBinary or FlashSize of plantNumber of unitsBinary or flashPumped or Self FlowO&M as % of cost

Economic DataFixed Charge RateUtilization Factor %Contingency %

Cost Modeling ResultsBinary Basin and Range Shallow Wells– 5000 ft wells, 150°C, 2000 gpm, Basin and Range drilling, Air-cooled binary plant, pumped wells

A. Basline Case Capital O&M Total % of allCosts

Expl & Conf 0.20 0.00 0.20 4%Well Field 0.32 0.04 0.36 7%Field, Other 0.21 0.29 0.50 9%Power plant 2.93 1.13 4.06 75%Royalty 0.00 0.13 0.13 2%Contingency 0.19 0.00 0.19 4%Total 3.86 1.59 5.45 100%% of all Costs: 71% 29% 100%

Break Down of Geothermal Power Cost

Binary Basin and Range Shallow Wells – 2000 ft wells, 150°C, 2000 gpm, Basin and Range drilling, Air-cooled binary plant, pumped wells

Cost Centers as Percentage of LCOE

4% 7%

9%

74%

2%

4%

Expl & Conf

Well Field

Field, Other

Power plant

Royalty

Contingency

Cost Modeling ResultsBinary Base Case – 5000 ft wells, 150°C, 2000 gpm, Basin and Range drilling, Air-cooled binary plant, pumped wells

Break Down of Geothermal Power Cost

Binary Base Case – 5000 ft wells, 150°C, 2000 gpm, Basin and Range drilling, Air-cooled binary plant, pumped wells

Cost Centers as Percentage of Total LCOE

8.6%

11.1%

7.7%

65.7%

3.1%

3.8%

Expl & Conf

Well Field

Field, Other

Power plant

Royalty

Contingency7.85 ¢/kW-hr

Cost Modeling ResultsFlash Base Case – 8000 ft wells, 200°C, 500K lb/hr, Basin and Range drilling, Dual Flash plant

A. Basline Case Capital O&M Total % of allCosts

Expl & Conf 0.74 0.00 0.74 14%Well Field 1.26 0.06 1.33 25%Field, Other 0.05 0.23 0.28 5%Power plant 1.71 0.77 2.48 47%Royalty 0.00 0.25 0.25 5%Contingency 0.19 0.00 0.19 4%Total 3.96 1.32 5.28 100%% of all Costs: 75% 25% 100%

Break Down of Geothermal Power Cost

Flash Base Case – 8000 ft wells, 200°C, 500K lb/hr, Basin and Range drilling, Dual Flash plant

Cost Centers as Percentage of LCOE

14.1%

25.2%

5.4%

46.9%

4.8%

3.6%

Expl & ConfWell FieldField, OtherPower plantRoyaltyContingency

5.28 ¢/kW-hr

Cost Modeling Results

A. Basline Case Capital O&M Total

Expl & Conf 1.60 0.00 1.60Well Field 10.88 0.97 11.85Field, Other 1.29 3.81 5.10Power plant 2.02 1.11 3.13Royalty 0.00 1.94 1.94Contingency 0.85 0.00 0.85Total 16.65 7.82 24.47% of all Costs: 68% 32% 100%

EGS High Temperature Case - 240°C at 6 km, pumped wells, 395 gpm

Cost Modeling ResultsEGS High Temperature Case - 240°C at 6 km, pumped wells, 510 gpm with technology improvement

B. Improved Case Capital O&M Total

Expl & Conf 1.05 0.00 1.05Well Field 3.07 0.79 3.86Field, Other 0.45 2.05 2.50Power plant 1.93 0.90 2.83Royalty 0.00 0.78 0.78Contingency 0.35 0.00 0.35Total 6.85 4.51 11.36% of all Costs: 60% 40% 100%

Break Down of Geothermal Power Cost

EGS High Temperature Case - 240°C at 6 km, pumped wells, 510 gpm, with technology improvement

Cost Centers as Percentage of LCOE

9.3%

33.9%

22.0%

24.9%

6.8%

3.1%

Expl & Conf

Well Field

Field, Other

Power plant

Royalty

Contingency11.36 ¢/kW-hr