Stanford UniversityGlobal Climate & Energy Project

Professor Sally M. BensonDirector, Global Climate and Energy Project

Stanford University

Science and technology for a low GHG emission world.

The Future of Energy:Technology for a Sustainable Energy System

50th Anniversary of the Japanese Associationof Groundwater HydrologistsMay 29, 2009

A Sustainable Energy System

SocietyAccessible

- Affordable- Abundant

- Reliable- Useful- Efficient- Equitable

EconomySecure

- Predictable- Competitive

- Resilient- Profitable- Compatible

with Nationalinterests

Environment

Protective- Air Quality

- Water Resources- Biodiversity

- Climate

Energy is the lifeblood of modern civilization.

The Challenge

How Do We Meet Growing Demands for EnergyWhile Protecting the Planet?

Society

Economy

Environment

Projected Energy Demand

50% increase in energy demand by 2030

0

100

200

300

400

500

600

700

800

1980 1985 1990 1995 2000 2005 2010 2015 2020 2025 2030

Energy Demand (EJ)

1 EJ = 1018 J EIA, International Energy Outlook, 2008

Global Energy Consumption

Global Energy Consumption (EJ)

0

100

200

300

400

500

600

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

1999

2001

2003

2005

HydroNuclearCoalGasOil

Source: BP World Energy Review, 2007

85% of world-wide energy consumption is from fossil fuels

Carbon Dioxide in the Atmosphere

0

2000

4000

6000

8000

10000

1760 1810 1860 1910 1960 2010

Car

bon

Dio

xide

Em

issi

ons

Carbon dioxide emissions have risen dramatically over the past two hundred years…

… leading to the buildup of carbon dioxide in the atmosphere,… global warming, and… ocean acidification.

M Tons (C)

IPCC, 2007

Haven’t Carbon Dioxide Concentrations Varied for a Long Time? Yes, but…

Unexplored territory

Difference during ice age

IPCC, Working Group 1, 2007

0

10,000

20,000

30,000

40,000

1760 1860 1960 2060

CO

2 E

mis

sio

ns

(MT

CO

2)Estimated Emission Trajectory to Stabilize

Atmospheric CO2 Concentrations

Peak

80% decreasefrom 2000

1990 Levels

A typical scenario for GHG emission reductions to limit warming to 2oC.

Historical Emission Data Needed Reductions

We need a portfolio of new technologies to achieve these reductions while meeting growing energy demands.

What Can We Do About This?

• Energy Conservation• Energy efficiency improvements• Low-carbon energy sources

Renewable energy (particularly solar and wind energy) Nuclear energy Geothermal energy

• Carbon dioxide capture and sequestration (CCS)

ProjectedCO2

Emissions

+Increased

Conservation

+Increased

EnergyEfficiency

+Renewable

Energy + CCS

The Global Climate and Energy Projectat Stanford University

Mission• Research on low-greenhouse gas emission

energy conversions• Focus on fundamental and pre-commercial

research• Applications in the 10-50 years timeframe

Strategy• Research projects with potential for significant

impact on reducing emissions• Look for potential breakthroughs for new

conversion options• High risk / high reward• Work at Stanford and at other institutions

around the world

Schedule and Budget• 10 years (2003 – 2013+)• $225 M

What resources can we use?Exergy flow of planet Earth (TW)

Humans use an average of 15 TW of energy or 450 EJ/year

Renewable Global Exergy Flows

0.1

1

10

100

1000

10000

SolarWind

Ocean Thermal G

radient

Waves

Terrestr

ial Biomass

Ocean Biomass

Geothermal H

eat Flux

HydropowerTides

Exergy sources scaled to average consumption in 2004 (15 TW)From Hermann, 2006: Quantifying Global Exergy Resources, Energy 31 (2006) 1349–1366

HumanUse of Energy(15 TW)

Global Exergy Stores

From Hermann, 2006: Quantifying Global Exergy Resources, Energy 31 (2006) 1349–1366

0

1

10

100

1000

10000

100000

Geothermal E

nergy*

Deuterium–trit

ium (from Li)

Uranium

Thorium

Coal

Gas Hydrates Oil

Gas

Yearly Human Consumption

Exer

gy (

ZJ)

What About Cost?

Source: J. Weyant, Energy Modeling Forum, Stanford University

Electric Generation Cost Comparison (2007 Fuel Prices)

0

0.05

0.1

0.15

0.2

0.25

0.3

Nuclear Coal Gas CC Gas CT Solar PV SolarThermal

Wind

Generation Technology

Fuel-2007

Variable O&M

$/KWHr(2007$s)

Key Messages: Energy Supply

• We are not running out of energy! Renewable energy flows: solar and wind power are largest resources Energy stores: large amount of geothermal, fossil fuels, nuclear fuels

• Using more renewable energy needs Lower the cost of electricity from solar energy Improve integration of wind into the electrical grid Develop methods for using renewable energy for transportation Deal with intermittency, seasonality, and geographic distribution Provide energy storage to support more wind and solar PV Enhance communications, control and transmission for the electric grid

to support more renewable energy• Using energy from fossil fuels needs

Reduce or eliminate carbon dioxide emissions from fossil fuels Switch to lower emission fuels (e.g. coal to natural gas)

• Using nuclear energy needs Resolve proliferation and waste disposal issues Gain public support for maintaining and expanding capacity

GCEP Research Portfolio

Research Projects in Solar Energy

Themo-Photovoltaic Cell – Fan et al.

Nano-Structured PV Cells - McGehee

Durable Nanostructured Cells With Si Quantum Dots –Green et al.

Wafer- based (c-Si)Thin-films (CIGS, CdTe)

“Third Generation”Concepts

Directed Evolution of Novel Yeast Species to allow fermentation of xylose, a major component of hemicellulose

OH

OH OO

Novel precursors for simplified degradation of lignin

Research Projects in Biofuels

New xylose utilizing strain

Non xylose utilizing strain

Novel screen for plants with enhanced saccharification

Cellulose fibrils

CESA4

CESA7CESA8

Increased cellulose accumulation for enhanced biomass

Lignincellulose

Hemicellulose

Research Projects in Hydrogen

Photo-activated Water Splitting at an Artificial Membrane – Lewis et al.

Hydrogen Storage in C-H bonds on Carbon Nanotubes –

Nilsson et al.

dissociation spillover

H

surface diffusion

GCEP Research Projects in Electrochemical Transformations

Innovative Battery Technologies for Improved Energy Densities Based on Nanowire Architectures - Cui

H2

Novel Approaches to Fuel Cell Design and Chemistry Nanoscale Architectural Engineering – Haile and Goodwin

AirO-

e-

H2O

O-

O-

e-

Anode CathodeElectrolyte

GCEP Research Projects in Carbon-Based Energy Systems

Advanced Combustion through Exergy Management – Edwards

Carbon Dioxide Capture and Sequestration - Benson

10% CO2 50% CO2

100% CO2

0% 100%50% 75%25%CO2 Saturation

CO2 Emissions Must be Reduced to Limit Global Warming

• 60% of global fossil fuel emissions come from large stationary sources

• Fraction could be much greater if we adopt electric cars

Power, 10539

Cement, 932

Refineries, 798

Iron and Steel, 646 Other, 462

Capture and Geologic Sequestration

CaptureDeep Underground

InjectionPipeline

TransportCompression

Types of Rock Formations Suitable for Geological Sequestration

Specific formation types• Oil reservoirs• Gas reservoirs• Saline aquifers• Deep unminable coal beds

Rocks in deep sedimentary basins are suitable for CO2 storage.100 km

Sacramento Valley, CaliforniaExample of a sedimentary basin with alternating layers of coarse and fine textured sedimentary rocks.

CO2 is Sequestered as a Supercritical Fluid

Density of CO2 (kg/m3)From IPCC Special Report

Gas

GasGas

GasSupercritical

Fluid

What Keeps the CO2 Underground?

• Injected at depths of 1 km or deeper into rocks with tiny pore spaces

• Primary trapping Beneath seals made of fine textured rocks

that provide a membrane and permeability barrier

• Secondary trapping CO2 dissolves in water CO2 is trapped by capillary forces CO2 converts to solid minerals

2 mm

Cappilary Barrier Effectiveness

1

10

100

1000

Delta PlainShales

ChannelAbandonment

Silts

Pro-DeltaShales

Delta FrontShales

ShelfCarbonates

Entry

Pre

ssur

e (B

ars)

Increasing Effectiveness

1.E-19

1.E-16

1.E-13

1.E-10

1.E-07

Gravel CourseSand

Siltysands

Clayeysands

Clay Shale

Perm

eabl

ity (m

2 )

Capillary Barrier Effectiveness

Some Attributes of Effective Storage Sites

Not to scale

Overburden

Seal

Sequestration Formation

Geographically extensiveLow permeability and high capillary entry pressureStable and sealed faults and fractures

Greater than 800 m deepNot a source of drinking waterSatisfactory injectivity Sufficient storage volumeHydrologically isolated from drinking water aquifers

Known condition of active and abandoned wellsPresence of secondary seals

Potential Groundwater Impacts

• CO2 migration into shallow aquifers Mild acidification, e.g. pH of 4 to 5 Potential mobilization of hazardous constituents, e.g. As, Pb

• Displacement and migration of saline brines into shallow aquifers

• Hydrocarbon migration into shallow aquifers e.g. methane, light hydrocarbon liquids

• Migration of gases co-injected with CO2 e.g. H2S, SO2, NO2

Potential for impacts depends on many site specific factors: seal properties, boundary conditions, size of injection, number and

condition of abandoned wells, initial hydraulic heads, and pressure buildup.

Rules of Thumb:Potential for Groundwater Impacts

Attribute Lower Risk Higher Risk

Reservoir Size Larger Small

Pressure Buildup Low High

Seal Properties Low permeability Higher permeability

Wells Few and well sealed Many and poorly sealed

Injection Fluid CO2 only CO2 + SO2 + H2S

Faults None or inactive Many and active

Risk Management to Protect Environment, Health and Safety

Regulatory Oversight

Remediation

Monitoring

Safe Operations

Storage Engineering

Site Characterization and Selection

Fundamental Storage and Leakage Mechanisms

Financial Responsibility

Multi-phase flow, trapping mechanisms, geochemical interactions, geomechanics, and basin-scale hydrology

Oversight for site characterization and selection, storage system operation, safety, monitoring and contingency plans

Financial mechanisms and institutional approaches for long term stewardship (e.g. monitoring and remediation if needed)

Active and abandoned well repair, groundwater cleanup, and ecosystem restoration

Monitoring plume migration, pressure monitoring in the storage reservoir and above the seal, and surface releases

Well maintenance, conduct of operations, well-field monitoring and controls

Number and location of injection wells, strategies to maximize capacity and accelerate trapping, and well completion design

Site specific assessment of storage capacity, seal integrity, injectivity and brine migration

Concluding Remarks

• There is no single solution to this challenge. We need to work on a broad portfolio of approaches, with a spectrum of time scales and sources of support.

• Need to get started now:

Do now: Conservation, energy efficiency, cost effective wind, solar and geothermal energy

Coming soon: Low emission base-load electricity generationNext generation lower cost solar photovoltaicsGrid integrated energy storageUpdated and more capable electricity grid

Ongoing: Research to provide plenty of new options

ProjectedCO2

Emissions

+Increased

Conservation

+Increased

EnergyEfficiency

+Renewable

Energy + CCS