Sally M. Benson Director, Global Climate and Energy Project

Stanford University

OCTOBER 10, 2012

GLOBAL CHALLENGES – GLOBAL SOLUTIONS – GLOBAL OPPORTUNITIES

GCEP RESEARCH SYMPOSIUM 2012 | STANFORD, CA

May 15-16, 2013

Lynn Orr Stanford University

Research at Stanford University in:

Carbon Mitigation and Advanced Combustion

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)

Reducing CO2 Emissions from Fossil Fuel Use

•  Improve combustion efficiency •  Capture and store some of the CO2 in the

subsurface •  Switch fuels to lower carbon content (coal to CH4

for electric power generation, for example)

Nuclear – 30% Coal – 30-40% Solar – 15% Natural Gas – 40-60% Wind – 50% Source: US EIA, http://www.eia.doe.gov/cneaf/electricity/epa/epata6.html

Average Conversion Efficiencies

0.1

1.0

10.0

100.0

1600 1700 1800 1900 2000 2100Time (Years A.D.)

Firs

t-Law

Effi

cien

cy (%

) .

Savery, Newcomen (<0.5%)Watt/Boulton Steam EnginesPost-Watt Steam EnginesLenoir, Hugon Coal-Gas EnginesOtto/Langen Coal-Gas EnginesAtkinson, Tangye Coal-Gas EnginesBanki Spirits EnginePriestman's Oil EngineDiesel's Oil EnginesAutomotive SI EnginesTruck Diesel EnginesLarge Bore DI DieselsSteam TurbinesGas Turbine/Steam TurbinePolymer Electrolyte Membrane FCPhosphoric Acid Fuel CellsSOFC/Gas Turbine

Conversion Efficiency of “Engines”

50%

Source: C. Edwards, GCEP

Advanced Coal Conversion - Supercritical Water Oxidation with CCS Reginald Mitchell and Chris Edwards, Stanford University

Analysis of full SCWO system shows overall efficiency of 37% and is a potential option for the efficient use of coal in electricity generation with zero emissions

to the atmosphere.

Enhanced Oil Recovery by CO2 Injection

•  If pressure is high enough, oil is displaced very efficiently in the swept zone.

•  Transfer of components between phases by phase equilibrium and chromatography is responsible.

Reservoir Displacement

•  Heterogeneity and gravity strongly influence well-to-well flow of injected gas.

•  Extremes of permeability dominate the flow. •  Low viscosity CO2 will find the easy flow paths between wells. •  Breakthrough of injected CO2 limits sweep efficiency and recovery. •  Stanford has performed decades of research to delineate the

physical mechanisms and model accurately the fluid flows in heterogeneous subsurface reservoirs

Example: CO2 Storage in a Gas Reservoir containing Condensate

ln(k)

Gas

Sat

urat

ion

Tota

l Mob

ility

Wave Velocity (z/t)

13 component fluid description (35% H2S), pure CO2 injection

Heterogeneous permeability field, 30 × 90 × 5 = 13,500 grid blocks

Numerical dispersion prevents finite-difference methods from resolving the condensate bank, except at very high grid resolution, even in 1D.

Sgas after 2500 Days Injection

Sgas

Compositional Streamlines 24 seconds

Finite difference 38,991 seconds

CSLS approach is 1600 times faster than FD (and the speedup scales as the number of grid blocks squared).

For large-scale compositional simulations sensitive to numerical dispersion, CSLS is the only feasible approach.

ERE CCS Faculty: Benson, Brandt, Kovscek, Tchelepi, Wilcox

Substituting Natural Gas for Coal in Electric Power Generation

•  Reduced SOx, NOx, particulate, Hg emissions

•  Reduced mining impacts, ash disposal

•  Reduced CO2 emissions per kWh generated: –  57% less CO2 per unit energy in

fuel for natural gas –  Better power plant efficiency

•  32% old coal •  35% NG single cycle •  60% NG combined cycle

•  CO2/kWh reductions: NG 48%, NGCC 70% (if no leakage of CH4)

Source: http://www.flickr.com/photos/davipt/164341428/sizes/l/in/photostream/

Source: http://www.sitheglobal.com/projects/goreway.cfm

14

Global Shale Plays

~22,600 TCF of Recoverable Reserves 6600 TCF from Shale (40%) Current use ~160 TCF/year

Major Reassessments Reported In England, Argentina and Bengal Province

Shale Gas Basins and Gas Pipelines, India & Pakistan

Source: US EIA, World Shale Gas Resources (ARI)

Shale Gas Research Questions

•  Adsorption, diffusion, and flow in nanoporous shales

•  Fracture properties, slow slip

•  CO2 adsorption, possible CH4 stimulation

•  Accurate long-term shale production modeling at field scale

•  Gas firming of intermittent renewables

Faculty: Brandt Wilcox Zoback

Conclusions •  Remaining fossil fuel resources are quite large: reducing

worldwide GHG emissions will require using them in very different ways in the future

•  Substituting natural gas for coal in electric power generation reduces CO2 emissions and has many other benefits (air quality, health, mining, …)

•  Shale gas: potential for significant additional supplies worldwide, many remaining research questions

•  Capturing and storing CO2 in the subsurface can contribute significantly to emissions reductions. Enhanced oil recovery is the primary initial target for economic reasons

Stanford Energy Research

18 earth  image  source  |  NASA