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