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An introduction to the geology behind Carbon Capture & Storage and Enhanced Geothermal Logan West Beijing Energy Network 6 Jan. 2010

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Slides from my presentation on CCS and Geothermal Energy to BEER on 6 Jan 2010 at the Bookworm

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Page 1: LW BEER 1.6.10

An introduction to the geology behind Carbon Capture & Storage and Enhanced Geothermal

Logan WestBeijing Energy Network6 Jan. 2010

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Three types of rocks◦ 1. Sedimentary – sandstone, limestone, shale

◦ 2. Igneous – granite, basalt

◦ 3. Metamorphic – marble, quartzite

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The Earth’s Layers Plate Tectonics

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Source: IPCC, 2005

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What do with the CO2?◦ Not up

◦ Not in the oceans

◦ How about the subsurface

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So what does the subsurface look like?

?

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Idealized SubsurfaceRealistically, sometimes complicated

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For the purposes of CCS, we are interested sedimentary basins, depressions in the earth’s crust into which sediments accumulate. They often have a bowl shape.

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Three main zones for CO2 injection:◦ Oil and Gas Reservoirs

◦ Deep Saline Aquifers

◦ Coal Beds

CO2 is injected in a supercritical state (31.1°C degrees C, >7.39MPa) so it behaves like a gas but with a density of a liquid◦ Doesn’t float away as quickly or easily

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Subsurface accumulations of oil and gas that are contained in porous rock layers and trapped by an impermeable formation above (caprock)

Common Reservoir Rock: sandstone, limestone, and dolomite

Common Caprock: shale, evaporite, or mudstone

With respect to CCS, they can be used for Enhanced Oil Recovery (EOR) and Enhanced Gas Recovery

Source: IPCC, 2005

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An aquifer is a body of permeable rock in which considerable amounts of water can be stored and through which groundwater flows

Geologically, it is essentially the same as an oil or gas reservoir. The greatest difference is that the fluid contained in aquifers is majority water rather than hydrocarbons.

Shallow aquifers are often used for drinking, the depth and high salinity of these aquifers make them undesirable for drinking, agriculture or industry

Source: CO2 capture project

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More unknown option

Due to the nature of the coal, CO2 will typically adsorb onto external pockets along coal deposits and overtime is absorbed into the coal

A driving factor for Coal bed storage is the opportunity for Enhanced Coal Bed Methane recovery (ECBM) in which CO2 replaces Methane (CH4) on the

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1. Stratigraphic Trapping

◦ A good caprock should be:

Laterally extensive

Will prevent vertical migration (low permeability, high capillary entry pressure, hydrocarbon trapping)

Expectations that present faults and fractures will seal

Adequate Rheological Properties

Info Source: WRI CCS Guidelines, 2008Images Source: http://www.co2captureproject.org/

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Stratigraphic Trapping

Structural Trapping◦ Heterogeneities

◦ Not only caprock blocks CO2

Source: http://www.co2captureproject.org/(left);

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Stratigraphic Trapping

Structural Trapping

Residual Trapping ◦ Stuck in the pore space

Source: http://www.co2captureproject.org/

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Stratigraphic Trapping

Structural Trapping

Residual Trapping

Solubility Trapping◦ CO2 dissolves into water

◦ No longer buoyant

Hydraulic Trapping

Source: http://www.co2captureproject.org

CO2 (g) + H20 H2CO3 HCO3- + H+

CO32- + 2H+

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Stratigraphic Trapping

Structural Trapping

Residual Trapping

Solubility Trapping

Mineralization◦ Bicarbonate (HCO3) formation

◦ Once it’s in mineral (i.e. solid) form, it’s stuck for millions of years

3 8 2 2 2 3 10 2 323 KAlSi O 2H O 2CO KAl OH AlSi O 6SiO 2K 2HCO

+ -

3 8 2 2 2 3 10 2 323 NaAlSi O +2H O+2CO NaAl OH AlSi O +6SiO + 2Na + 2HCO

2 2 8 2 2 4 3 10 3 24 23 CaAl Si O +4H O+4CO CaAl OH AlSi O + 2Ca(HCO )

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Storage Mechanisms Storage Risks

Source: WRI, 2008

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Key Parameters:◦ Capacity Can it hold all the CO2?

Factors: size of reservoir, volume of pore space, CO2 density

◦ Containment Will it stay there?

Factors: Caprock Integrity, effect of other storage mechanisms

◦ Injectivity Can we pump it in as fast as it’s piped to the site?

Factors:Permeability

Basin Depth between 800–3000m – for supercritical state ◦ Behaves like a gas but dense like a fluid (keeps it from “floating” away

quickly)

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Image Source: The World Bank, The cost of pollution in China, 2007

Economics

Conflict of interest (minerals, petroleum, water)

Protected areas

Population

Etc.

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Thorough Site Selection and Characterization

Monitoring plan◦ Start prior to injection

◦ Continue decades after injection

Reservoir Models◦ Create as you learn about the geology

◦ Update with monitoring data

◦ Use to predict how CO2 will move overtime

Risk Analysis◦ Identify known storage risks

◦ Create plans for how to protect against them

◦ Be prepared with plans if leakage does occur

Source: IPCC, 2005

Seismic Monitoring

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Similar anthropogenic projects or natural formations◦ Acid gas (H2S) underground injection

◦ Liquid waste underground injection

◦ Natural CO2 reservoir

Thus far proven in CO2 Storage demonstrations

IPCC Quote:

In Salah, Algeria

Weyburn, Canada

Sleipner, Norway

“Observations from engineered and natural analoguesas well as models suggest that the fraction retainedin appropriately selected and managed geologicalreservoirs is very likely25 to exceed 99% over 100 yearsand is likely20 to exceed 99% over 1,000 years.”

Source: IPCC, 2005

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CO2 in heavy concentrations (>7-10% air composition can lead to human death)◦ Is denser than air so can accumulate in low lying areas until

is dispersed by wind

Forms carbonic acid in water ◦ Render water non-potable, bad for agriculture◦ Can leach heavy metals

Can lead to acidification of soil◦ Bad for organisms◦ Can leach heavy metals – worse for organisms

There are means of remediation to plug leaks and minimize impacts

Source: IPCC, 2005

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Storage ProspectivityEmissions for Storage Regions

Source: APEC 2005

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NRDC:

PNNL: China may have 2,300 Gt (>100yr demand) of onshore CO2 storage capacity:

• 2,290 Gt in deep saline formations• 12 Gt in coal seams • 4.6 Gt in oil fields • 4.3 Gt in gas fields

Source: http://www.nrdc.org/international/chinaccs/default.asp

Source: PNNL, Establishing China’s Potential for Large Scale, Cost Effective Deployment of Carbon Dioxide Capture and Storage, October 2009, PNNL-SA-68786

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Storage in China faces several challenges◦ Geological Complexity

◦ Local Capacity Issues for EOR

◦ Unmarked, poor quality wells – potential leakage sources

◦ Data Accessibility – overall lack of data, data that exists often proprietary to oil, gas, and mining companies

Data

Availability

Capacity

Envelope -

Volume and

Reservoir

Quality

Geological

ComplexityContainment Injectivity Well Integrity

Reservoir

Availability

Pipeline

Distance

Conflicts of

Interest

Dagang Oilfield Province

Shengli Oilfield Province

Huimin Sag Saline Formations

Kailuan Mining Area

Low risk

Medium risk

High risk

Source: Espie, T. COACH WP4: Recommendations and Guidelines for ImplementationCOACH-NZEC Conference, 28 Oct. 2009

Image showing relative risk in possible storage fields in China’s Bohai Basin

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Storage capacity◦ oil fields: from 10 to

500MtCO2

◦ Deep saline aquifers: ~ 20GtCO2

◦ Coal mines: 500GtCO2 BUT availability and injectivity questionned due to extremely low permeability

Source: Kalaydjian, F. Key findings from NZEC Phase I: COACH OverviewPresented at NZEC-COACH Conference, Oct. 28, 2009

• Further analysis doesn’t necessarily support theoretical estimates

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Continue In-depth investigation to achieve more realistic capacity estimates and identify exact storage sites

Improve access to data

Begin storage demonstration projects

Continue to improve reservoir modeling and characterization technology

Define tools and best-practice for site characterization and monitoring

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ENHANCED GEOTHERMAL

SYSTEMS (EGS)

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WHAT DOES GEOTHERMAL MEAN?

The Earth’s core is ~5,500C.

Convection, Conduction, and Radiation transport

heat to the crust

Geothermal Gradient

Average surface temperature is 15C

Temperature increases with depth at a rate ranging

from 15 C/km to 50 C/km

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HOW DO WE USE GEOTHERMAL ENERGY?

Direct Use: Heat Pumps, Bathing, Space

Heating, etc

2000 75,000+ GWh worldwide usage

Electric Power Generation: via steam powered

turbines

2003 56,000+ GWh worldwide usage

Source:Glitner US Geothermal Energy Market Report 2007

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WHAT ARE ENHANCED GEOTHERMAL

SYSTEMS (EGS)?

Hydrothermal Energy: natural hot springs

Shallow: < 3km depth

In situ, High Temp Water: > 150C

Limited Resources

Enhanced Geothermal

Deep: 3 – 10km depth

Hot Rocks: Temperatures ranging 150 to 400+C

No Natural Reservoir: Reservoir must be created and

water pumped in

Vast Resources

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BEST EGS REGIONS

Looking for High Heat Flow and/or High

Temperature Gradients

Plate Boundaries – Geologically Active

Sedimentary Basins

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USA GEOTHERMAL RESOURCES

Source: MIT Future of Geothermal Energy, 2006

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Simplified cartoon rendering of EGS plant (left) and schematic of Geothermal Binary Power Plant (right): http://www.geothermal-energy.org/geo/geoenergy.php

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KEYS FOR SUCCESS

Most important factor is Flow Rate

Combination of permeability, volume of fractured

rock, surface area of fractured rock

Need to have as little loss of water as possible

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POTENTIAL FOR EGS

USA Recoverable Resource1:

In the USA alone, 28.95 million Terrawatt hours

Could power the world for 590 years at 2007

consumption levels

Other countries beginning to do analyses

Predicted USA Development of EGS through the

year 2050 (MWe)2:

2015 2025 2050

1,000 10,000 130,000

1: Values from MIT Future of Geothermal Energy (2006) and BP Statistical Review of World Energy 2007 2: NREL Geothermal Resources Estimates for the US 2006

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ADVANTAGES OF EGS

Renewable

Energy Security

Limits demand for fossil fuels

Every Nation possesses some geothermal resource

Baseload Power Source

Constant, non-fluctuating energy

Hydrothermal Plants operate at 95% capacity

Economically competitive

Cost currently estimated 8-14 cents/hr

Tremendous incentive for natural technology growth

Minimal Environmental Impact

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ENVIRONMENTAL BENEFITS OF EGS

Near Zero Emissions*

Limited Plant Surface Area*

7x less than Nuclear; 35x less than Coal

Induced Seismicity comparable to oil, gas, and

mining operations

Environmental

Emissions for U.S.

Power Plants

Carbon Dioxide

(CO2)

(Lbs/MWh)

Sulfur Dioxide (SO2)

(Lbs/MWh)

Nitrogen Oxide

(NOx)

(Lbs/MWh)

New Coal Plant** 2068 3.6 2.96

Old Coal Plant 2191 10.39 4.31

New Natural Gas Plant 850 0.018 0.31

Geothermal Flash

Plant60 .35*** 0

Geothermal Binary

Plant0 0 0

* Data from NREL Geothermal Report

** New = Coal Plants built in 1990s; natural gas combined cycle plants built in 2002

*** This is indirectly

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POTENTIAL PROBLEMS

Induced Seismicity

Hydrofracturing rocks by nature sets of micro-

earthquakes

Recorded magnitude 3.2 earthquake in Basel,

Switzerland argued to be caused by local EGS plant

There are over 130,000 Magnitude 3-3.9 earthquakes

in the world each year with minimal damage at most1

A magnitude 4.9 (almost 100x greater than Basel)

occurred in Yunnan New Year’s Day 2010. It received

no press.

Technological Difficulties

1: USGS

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WHAT STAGE IS EGS DEVELOPMENT AT?

Successes1:

Pilot projects can create reservoirs, generate power on the

scale of a few megawatts

Power plants already capable of converting supercritical

water (temp of 400 C) into electricity

Technological Obstacles:

Better control of reservoir creation

Drilling equipment withstand > 5km depth and 200C

environment

Maintaining a commercially viable, production flow rate

Economic Obstacles2:

Capital Intensive (drilling and plant construction)

Overcoming initial “Valley of Death” investment (est.

US$3.5 million per MW)

1: Source – MIT Future of Geothermal Energy 2006 2: Glitner US Geothermal Energy Market Report 2007

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GEOTHERMAL RESOURCES OF CHINA:

HEAT FLOW

Source: Hu et. al., 2001

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GEOTHERMAL REGIONS OF CHINA

High Grade Medium to Low Grade

Source: Pang, 2009 http://english.iggcas.ac.cn/pangzhonghe/index.html

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CHINA, GEOTHERMAL, & EGS

China is the world leader in total Direct Use geothermal energy1

China only utilizes 5% of hydrothermal resources it deems economically exploitable2

Southwest China (Tibet, Sichuan, and Yunnan) and the Southeast Pacific coast possess large high-grade geothermal resources2

Sedimentary Basins (also a key source) cover 36% of China3

Currently China has only one hydrothermal power plant in operation at Yangbajain (28 MW) providing ½ of Lhasa’s electricity2

If China were to possess only 1/10th of the recoverable resources of the USA, it could still meet its 2008 primary energy demand for 333 years4

1: Glitnir US Geothermal Energy Market Report 2007; 2: Ministry of Land and Resources; 3: Pang, Z. 2009; 4: Calculations from Data of MIT & BP Reports

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POTENTIAL NEXT STEPS FOR CHINA

Conduct full Geothermal resource assessment

Already has plans for new hydrothermal resource

assessment

Promote investment of deep drilling technology

investment and other Geothermal Technologies

Further develop its hydrothermal resources

Plan for EGS pilot plants based on finding of

geothermal resource assessment

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ACKNOWLEDGMENTS

Tsinghua-BP Center

World Resources Institute

National Resources Defense Council

Princeton In Asia

Zhang Dongjie