Geothermal Energy

Patrick (Pat) LaneyIdaho National Laboratory

Utah Geothermal Power Generation Workshop

August 17, 2005

Oceanic crust: depth of 0-10 kmThe oceanic ridge system, a 40,000 km network of volcanoes, generates new oceanic crust at the rate of 17 km3 per year

Continental crust: depth of 0-75 kmThe outer part of the Earth composed essentially of crystalline rocks. These are low-density buoyant minerals dominated mostly by quartz and feldspars. We refer to this rigid outer shell as the lithosphere (the rocky or strong layer).

The Big Picture – Geothermal 101

The “Ring of Fire”

Where Are We Likely To Encounter High Subsurface Temperatures?

3km

4km

5km

6km

10km

Estimated temperatures at various depths from

9,800 - 32,800 ft. (3 - 10km)

The Geothermal Water Cycle

How Do You Find Geothermal Resources ?Early resources were found primarily by:

• Visual observations of existing springs & thermal features

• Elevated temperatures in shallow domestic and industrial wells

Yellowstone National Park

Firehole River Yellowstone National Park

Artesian Geothermal Well

Finding Geothermal Resources

-117.94 -117.92 -117.90 -117.88 -117.86 -117.84 -117.82

39.92

39.93

39.94

39.95

39.96

39.97

39.98

39.99

40.00

Dixie Valley

Stillwater Range

Shallow TG W ell

Deep TG W ell

Steam W ell

Other Deep W ells

36-14 & 62A-23

DVPP/OXBOWThermal Gradients °C/Km

W ELL INDEX

Range bounding fault

DVPP Lease

Alteration Zones

Senator Fumaroles

Oxbow FieldLandslide

Section 10/15 Fumaroles

Section 7 producers

Section 18 Injectors

Section 33Producers

Section 5Injectors

82-5

62-21

62A-23

36-14

66-21

45-14

1 k m

Cottonwood Creek

53-15

76-28

Field reconnaissance and geologic mapping were

responsible for early discoveries

Many early exploration techniques from petroleum exploration were

incorporated

0 5000 10000 15000 20000 25000 30000

DISTANCE, FEET

-25000

-20000

-15000

-10000

-5000

0

DE

PT

H,

FE

ET

TERTIARY BASALTS & TUFFS

O ne Fa ult

Se na to r Fum a ro le s

BASEMENT

N o V ertica l E xaggeration

( )

VALLEY FILL

?

Majority oftopographicoffset here

Majority of valleyoffset here

N W S E

Finding Geothermal Resources

Modeling Seismic Surveys InSAR

• Satellite Imagery

• Gravity Surveys

• Seismic Surveys

• Geochemical Surveys

• Modeling

Current exploration practices include a wide array of physical and remote sensing measurements including:

• Multispectral imaging

• Soil mapping

• Geothermometry• Vegetation mapping

• InSAR

Finding Geothermal Resources

You Have To

Drill !

G A 0 2 - 5 0 6 8 3 - 2 4

Generator

Iso-Butane

ProductionWell

InjectionWellGeothermal Zone

Water

Heat Exchanger

Air and Water Vapor

Air

Pump

Air

Water

CoolBrine

Condenser

Geothermal Electrical Power

• Dry Steam• Flash Steam• Binary

Environmentally FriendlyG A 0 2 - 5 0 6 8 3 - 2 2

Generator

Steam

ProductionWell

InjectionWellGeothermal Zone

Waste Brine

Water

Air and Water Vapor

Air

DirectHeatUses

Air

“As we know, there are known knowns. There are things we know we know. We also know

there are known unknowns. This is to say, we know there are

some things we do not know. But there are also unknown

unknowns, the ones we don’t know we don’t know.”

Donald Rumsfeld