Geothermal EnergyResources

San Jose State University

FX RongèreMarch 2009

Geothermal Energy Resource

Huge resource: At 10 km under the ground the resource are 13 M

Quads Equivalent of 130,000 year of USA energy overall

consumption 100 GWe possible in the USA by 2050

In California, Geothermal Energy is big:

Source: CEC-300-2007-0072006 NET SYSTEM POWER REPORT

2,068 MW installed in California in 2006 compared to 2,313 MW for the USASource: EIA.gov

Types of Geothermal Energy

3 types of Geothermal Energy Power Generation (>3km - >150oC) District Heating (500m - <100oC) Geothermal Heat Pumps (100m - <20oC)

Source: http://www.geothermal.ch/eng/vision.html

Geothermal Resource

http://www.worldbank.org/html/fpd/energy/geothermal/technology.htm

Heat comes from the core of the earth, the natural earth radioactivity, and chemical reactions

Estimation of the heat flux

Conduction through the lithosphere

Ad

TTknTgradkQ

crust

MSA

Acond ....

k Thermal conductivity of the crust (2 W.m.K-1)

TS Temperature at the surface of the crust (20oC)

n Normal to the surface

TM Temperature of the surface of the mantel ( 930oC)

dcrust Depth of the crust is about 30 km

A Area (1 m2)

206.0

WmQcond

Capture the energy deep in the crust

Water flow allows much higher fluxDrill a well deep enough to get the

required temperature

Assuming uniform crust depth

Average temperature gradient in the crust

0

5

10

15

20

25

30

0 200 400 600 800 1,000

Temperature (C)

Dep

th (km

)

Plate Tectonics

Best resources are at the boundaries of main plates

Current Drilling Cost

Source:The Future of Geothermal Energy 2006

Geothermal Resources USA

Geothermal Resources USA

Geothermal Resources USA

Geothermal Resources USA

California Geothermal Resources

Geothermal Power Plants

Glass Mountain 49 MW 96AmedeeHoney Lake 4 MW 85-89Geysers 1,421 MW 71-89Casa DiabloMammoth 40 MW 84-90Coso 274 MW 87-89Salton Sea 336 MW 82-00Heber 85 MW 85-93East Mesa 99 MW 87-89TOTAL 2,308 MW