GEOTHERMAL ENERGYCatherine Hillard

Jaymie Trask

Trevor Larson

Overview• THREE KEY ISSUES

• Geothermal Reservoirs• Geothermal Energy Production• Geothermal Energy Cost

• GLOBAL IMPACTS

• SOCIETAL IMPACTS

• ROLE OF THE CHEMICAL ENGINEER

Geothermal Reservoirs • Heat from the Earth • Clean, renewable resource• Temperatures between ~200˚F and 700˚F• U.S. Commercial power since 1960s. • International market.

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Reservoirs

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Reservoirs • ~4,000 miles deep• ~5,500°C• 42 million megawatts (MW) per year• Geothermal is constantly available

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Production

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Production

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Production

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Production

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Production

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Production

http://srren.ipcc-wg3.de/report/IPCC_SRREN_Ch04.pdf

Geothermal Energy Production• High-pressure geothermal water separates into steam and water• 900 MW of the 3,187 MW of installed geothermal capacity in the U.S

http://www.geo-energy.org/reports/Gea-GeothermalBasicsQandA-Sept2012_final.pdf

Geothermal Energy Cost

http://srren.ipcc-wg3.de/report/IPCC_SRREN_Ch04.pdf

Social Impacts• Plants produce some sludge

• Zinc, sulfur, silica, etc.

• Small visual impact• No storage, transportation, or combustion fuels

• Lower energy cost per kWh• BHP currently $0.0825• Geothermal about $0.05

Sources: http://srren.ipcc-wg3.de/report/IPCC_SRREN_Ch04.pdfhttp://www1.eere.energy.gov/geothermal/faqs.html#geothermal_energy_cost

Social Impacts• 90% availabilities or higher

• Coal only 75%

• May cause sink holes from voids• Wairakei sinks 0.5 meters per year since power station (New

Zealand)

Sources: http://www.teara.govt.nz/en/geothermal-energy/page-5 http://www1.eere.energy.gov/geothermal/faqs.html#geothermal_energy_cost

Global Impacts• Low emissions compared to coal plants

• Can be utilized almost anywhere• Steam reservoirs• Heat pumps• Magma awaiting technology

Sources: http://srren.ipcc-wg3.de/report/IPCC_SRREN_Ch04.pdfhttp://www1.eere.energy.gov/geothermal/faqs.html#geothermal_energy_cost

Global Impacts• Increase rate of natural emissions

• Removes heat from reservoirs 10x replenishment

• Renewable resource• Recycle the material back to energy source

Sources: http://srren.ipcc-wg3.de/report/IPCC_SRREN_Ch04.pdfhttp://www1.eere.energy.gov/geothermal/faqs.html#geothermal_energy_cost

Role of Chemical Engineers• EGS

• CO2ETM

• Small scale heating

• Research and Development

Enhanced Geothermal Systems• Apply small forces to stimulate rock layers to slip

• Different than oil and gas “fracking”

• Hot rock and cool water• Thermal Contraction

• Closed Loop Technology

http://www.geysers.com/systems.aspx

Enhanced Geothermal Systems

• Favorable EGS • Temps at ~2-6 miles below surface

http://www.geysers.com/untapped.aspx

CO2ETM

• GreenFire Energy

• St. John’s Dome formation near Springerville, AZ

• Compress CO2 and pump underground

• Carbon Sequestrationhttp://energy.gov/articles/innovative-geothermal-startup-will-put-carbon-dioxide-good-use

Discussion• Is geothermal energy more economically feasible than

coal powered plants?

• Where can CO2ETM be applied across the US?

• What are some risks associated with geothermal energy?