Sustainable Energy:

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Sustainable Energy Challenges and
Solutions STEM Scholars Lecture
Series California State University
Sacramento February 27, 2007
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Sustainability

• Meeting the needs of the present without
  compromising the ability of future generations to
  meet their needs.
• Criteria for Sustainable Energy
• Fuel Supply not Depleted with Use
• Properties of Earth/Atmosphere Unaltered
• No Significant Social Injustices

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Energy Supply
320,000,000,000 Gallons of Petroleum 1,000,000,000
Tons of Coal 22,000,000,000,000 Cubic
Feet Natural Gas
36 Imported (Petroleum and Natural Gas) 85 From
Fossil Fuels
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Energy Lifecycle Automobile
H2O CO2
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Energy Lifecycle Automobile
CO2 NOX H2O CO Energy (Transportation)
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Combustion Products
NOX VOC Sunlight Ground Level Ozone
CO2 H2O
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Combustion Products
C8H18 12.5 (O2 3.76 N2) ? 8 CO2 9 H2O
47 N2 1 kmol fuel ? 8 kmol CO2 1 kg fuel ? 3 kg
CO2 One 16 gallon tank ? 320 lbs CO2 U.S. CO2
Emissions 6.5 Billion Tons Worldwide CO2 30
Billion Tons
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Global CO2 Concentrations
Data from Mauna Loa Observatory, Hawaii
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Climate Change
Long Wavelength, Low Energy
Short Wavelength High Energy
CO2
11 of Last 12 Years Rank Among the 12 of the
Warmest Since 1850 Average Temperature Risen
1.5?F Since 1900 Sea Levels Have Risen 7 inches
in the Last Century
CO2
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Climate Change

• So its a Little Warmer,
• Whats the Big Deal?
• Avg. Temp. to Increase 3 to 9? F by 2100
• Oceans to Rise 7 to 31 Inches by 2100
• More Frequent and Stronger Hurricanes
• Extreme Weather
• Ecosystems and Habitat Loss
• Glacier Retreat
• Economic Impacts

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Climate Change
February 2002 March 2002 Larsen B Ice
Shelf 200 m thick, 3200 km2
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Climate Change
February 17, 1993 February 21,
2000 Receding Snows of Mount Kilimanjaro,
Tanzania, Africa Expected to Be Gone By 2020
Image courtesy of the Image Science Analysis
Laboratory, NASA Johnson Space Center
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Sociopolitical Injustices?
Photos courtesy of Associated Press and Emirates
Palace, Abu Dhabi
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Fossil Fuel Sustainability

• Depleting Fuel Reserves
• Best Estimate 40-80 years
• Undiscovered Reserves Uncertain
• Proven Reserves Uncertain (OPEC)
• What is Certain?
• Demand Increasing
• Supply Decreasing
• Atmospheric CO2 Concentration Increasing
• Economic, National Security Issues

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Renewable Technologies

• Renewable Technologies
• Direct Solar Thermal and PV
• Indirect Solar
• Biomass
• Wind
• Wave
• Other Sources
• Geothermal
• Tidal

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Solar Thermal
Active Solar Collector, Rooftops Passive
Integrating Low Energy Design
Domestic Hot Water Pools/Spas Residential Space
Heating Adsorption Refrigeration Industry/Processi
ng
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Solar Collectors
Flat Plate Collector (0-50 ?C Rise)
Black Absorber (0-10?C Rise)
Glass
Insulation
Water
Evacuated Heat Pipe (10-100 ?C Rise)
Focused Collector (50-150 ?C Rise)
Water
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Solar Collectors
Evacuated Heat Pipe Water Heater
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Passive Solar Heating
Trombe Wall
Conservatory
Warm
Warm
Cool
Outside Air
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Solar Photovoltaic
Photons
Antireflective Coating
n-type Semiconductor




-
-
-
p-type Semiconductor
-
Backing

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Solar Summary

• Benefits
• Simplicity
• Availability vs. Demand Peak-Summer
• Cost-effectiveness
• Challenges
• Intermittent and Little Availability in Winter
• Energy, Cost of PV Cell Production
• Whats Next?
• Widespread Use
• New PV Applications (Thin Film, Flexible)

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Bioenergy
Biomass All of the Earths Living
Matter Biofuels Fuels Derived from Biomass
Respiration
CO2
Low Temperature Heat
CO2
Bioenergy
CO2
CO2
Heat and Electricity
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Bioenergy

• Traditional Combustion of Raw Biomass
• New Transform Properties (Liquid, Gas)
• Utilize Waste and Replace Fossil Fuels
• Reduce Pollutant Emissions
• Examples
• Woody Crops Forestry
• Agricultural Switch Grass, Corn, Oil Seeds
• Wastes
• Agricultural (Rice Husks, Corn Shucks, etc)
• Animal (Dairy, Sewage)
• Commercial (Sawdust, Tires, Landfill Gas)

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Biofuels Ethanol
Abengoa Bioenergy Facility in York County,
Nebraska Ethanol Production Capacity 50 Million
Tons per Year
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Bioenergy Summary

• Benefits
• Availability
• Worlds Biomass Energy Storage?? 95 TW
• Worlds Energy Consumption ? 15 TW
• Existing Equipment, Infrastructure
• Waste Utilization, Potentially Carbon Neutral
• Scheduling Control
• Challenges
• Energy Balance and Economics
• Improve New Biofuel Processes
• Increase Production Capacity

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Wind Energy

• Sun Heats Earth Unevenly
• Buoyancy
• Regional Pressure Differences

Wind
Ocean
Land
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Wind Energy
The Aerofoil

• Wind Turbines
• Lift and/or Drag Forces in Direction of Rotation
• Vertical or Horizontal Axis
• Most Common 3-Bladed, Horizontal Axis
• Typical Efficiencies 20-30

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Wind Energy

• Wind Turbines or Bird Blenders?
• Avian Deaths (U.S. per Year)
• Wind Turbines 30,000
• Communications Towers 40 Million
• Pesticides 67 Million
• Vehicles 70 Million
• Cats 100 Million
• Utility Lines 150 Million
• Windows 500 Million
• Altamont Location, Tower Design, Spacing

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Wind Energy
SMUD Solano Wind Project, Rio Vista, CA
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Wind Energy Summary

• Benefits
• Economical
• High Initial Investment
• Low Maintenance, No Fuel Costs
• Minimal Air, Water, Land Pollution
• Scalability (1 kW to 3 MW)
• Many Good Locations
• Challenges
• Visual Pollution
• Intermittency and Predictability

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Wave Energy
Winds
Turbulent Air Flow
Shear Stress on Surface of Water
Wind Flow on Upwind Wave Faces

• Solar Radiation ? Wind ? Waves
• Wave Size Factors
• Wind Speed
• Wind Duration
• Distance Over Which Wave Travels

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Wave Energy
Oscillating Water Column (OWC)
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Wave Energy
The 500 kW LIMPET OWC, New Zealand
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Wave Energy
Pelamis (Sea Snake)
Accumulated Fluid Drives Turbines, Generators
Hydraulic Rams Pump High Pressure Fluid
A Few Other Ideas Whale Frog Dragon Clam Swan
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Wave Energy
The 750 kW Pelamis Wave Energy Converter, Portugal
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Wave Energy

• Benefits
• Waves Concentrated Solar Energy
• Demand in Phase with Availability (Winter)
• Low/No Chemical Pollution
• Low Visual Pollution (Offshore)
• Large Potential Resource (Estimated 2 TW)
• Challenges
• Electricity Transmission
• Immature Technology
• Potential Shipping, Boating Accidents

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Tidal Energy

• Gravitational Force
• Proportional to Mass of Earth, Moon
• Inversely Proportional to Distance Squared

Maximum Gravitational Force High Tide
Minimum Gravitational Force
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Tidal Energy

• Centrifugal Force
• Earth-Moon System
• Spinning Through Space

Center of Mass
Minimum Centrifugal Force
Maximum Centrifugal Force High Tide
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Tidal Energy
Large Generating Capacity (Many MW) Two Large 3.0
to 5.0 Hour Bursts per Day Four Smaller 1.5-3.0
Hour Bursts per Day
Flood Generation
Ebb Generation
?h
?h
Ocean Reservoir
Ocean Reservoir
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Tidal Energy
Tidal Barrage at La Rance, France 240 MW
Capacity 333 m Long 8 m Tidal Range
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Tidal Energy

• Benefits
• Tremendous Electricity Generation Potential
• No Green House Gas, Pollutant Emissions
• Predictable
• Challenges
• Environmental Impact
• Modifying Water Levels Behind Dam
• Less Variation, Affecting Birds and Fish
• Shipping, Boating
• Tremendous Initial Cost
• Intermittency

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Geothermal Energy
Independent of the Sun Radioactive Isotopes,
Gravitational Energy
340 W/m2
Geothermal Plant
Hot Springs
Impermeable Rock
0.05 W/m2
Steam
Water
Water
Impermeable Rock
Liquid Hot Magma
Impermeable Rock
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Geothermal Energy
Many Possible Configurations
Steam Turbine
Electricity to Grid
Generator
Cooling Tower
Flash Chamber
Heating, Processing
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Geothermal Energy
One of twenty-one plants at the Geysers, Sonoma
and Lake Counties, CA The Geysers Provides 850 MW
to Power about 750,000 Homes
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Geothermal Energy

• Benefits
• No Intermittency
• Low/Zero Pollutant Emissions
• Challenges
• Source Depleted (Energy Mining)
• 2501 Use to Recharge Rate
• Limited Sources
• High Quality Sources Tapped
• Most Near Tectonic Plate Interfaces
• Better Utilize Low Quality Sources
• Ground Source Heat Pump

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How do we get Sustainable?

• As Citizens
• Reduce, Reuse, Recycle
• Drive a Fuel Efficient Car
• Dont Drive (Telecommute, Public Trans)
• Make Your Home Energy Efficient
• Insulation, Caulking and Door Seals
• Tune Heater and Air Conditioner
• High Efficiency Appliances and Lights
• Install Renewables
• Plant Trees

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How do we get Sustainable?

• As Scientists, Engineers and Mathematicians
• Traditional Technologies
• Efficient Gasoline and Diesel Vehicles
• Cogeneration and Carbon Sequestration
• Energy Efficiency and Management
• Research, Develop Emerging Technologies
• New Biofuel Sources
• Fuel Cells and Hydrogen
• New Technologies and Applications
• Bring Sustainable Products to Market
• Transparent, Cost Effective

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Sacramento State Expertise

• Solar Thermal
• Solar Heating and Adsorption Refrigeration
• Efficient Building Design
• Biofuels and Combustion
• Conversion of Biomass to Alcohol Fuels
• Mesoscale and Distributed Power Systems
• Ultra-Low Emissions Combustion
• Stationary Power Fuel Cells
• New Fuel Cell Types
• Parametric Study and Computer Simulation

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Clean Energy Center

• Internal Student Learning through Research
• External Regional Clean Energy Growth
• Mission Contribute to Sustainable Energy in the
  Sacramento Region with Education and Research
• Goals
• Promote Collaboration within Sac State
• Foster External Relationships
• Facilitate External Funding and Publication
• Create Authentic Learning Experiences
• Provide Technical Expertise to Startups

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Photo Credits
John Gilardi SMUD General Motors NASA Emirates
Palace Solar Innovations, Inc Abengoa
Bioenergy Wavegen Voith Siemens Hydro Power
Generation Ocean Power Delivery, Ltd. Icelandic
National Energy Authority Calpine, Corp.