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Sustainable Energy: Challenges and Solutions STEM Scholars Lecture Series California State University Sacramento February 27, 2007. Sustainability. “Meeting the needs of the present without compromising the ability of future generations to meet their needs.”
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Sustainable Energy: Challenges and Solutions STEM Scholars Lecture Series California State University Sacramento February 27, 2007
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
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
Energy Lifecycle: Automobile H2O CO2
Energy Lifecycle: Automobile CO2 NOX H2O CO Energy (Transportation)
Combustion Products NOX + VOC + Sunlight = Ground Level Ozone CO2 H2O
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
Global CO2 Concentrations Data from Mauna Loa Observatory, Hawaii
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 1.5F Since 1900 Sea Levels Have Risen 7 inches in the Last Century CO2
Climate Change • So it’s a Little Warmer, • What’s 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
Climate Change February 2002 March 2002 Larsen B Ice Shelf – 200 m thick, 3200 km2
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
Sociopolitical Injustices? Photos courtesy of Associated Press and Emirates Palace, Abu Dhabi
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
Renewable Technologies • Renewable Technologies • Direct Solar Thermal and PV • Indirect Solar • Biomass • Wind • Wave • Other Sources • Geothermal • Tidal
Solar Thermal Active –Solar Collector, Rooftops Passive – Integrating Low Energy Design Domestic Hot Water Pools/Spas Residential Space Heating Adsorption Refrigeration Industry/Processing
Solar Collectors Flat Plate Collector (0-50 C Rise) Black Absorber (0-10C Rise) Glass Insulation Water Evacuated Heat Pipe (10-100 C Rise) Focused Collector (50-150 C Rise) Water
Solar Collectors Evacuated Heat Pipe Water Heater
Passive Solar Heating Conservatory Trombe Wall Warm Warm Cool Outside Air
Solar Photovoltaic Photons Antireflective Coating n-type Semiconductor + + + + - - - - p-type Semiconductor Backing +
Solar Summary • Benefits • Simplicity • Availability vs. Demand: Peak-Summer • Cost-effectiveness • Challenges • Intermittent and Little Availability in Winter • Energy, Cost of PV Cell Production • What’s Next? • Widespread Use • New PV Applications (Thin Film, Flexible)
Bioenergy Biomass – All of the Earth’s Living Matter Biofuels – Fuels Derived from Biomass Respiration CO2 CO2 Low Temperature Heat Bioenergy CO2 CO2 Heat and Electricity
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)
Biofuels: Ethanol Abengoa Bioenergy Facility in York County, Nebraska Ethanol Production Capacity: 50 Million Tons per Year
Bioenergy Summary • Benefits • Availability • World’s Biomass Energy Storage 95 TW • World’s 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
Wind Energy • Sun Heats Earth Unevenly • Buoyancy • Regional Pressure Differences Wind Ocean Land
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%
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
Wind Energy SMUD Solano Wind Project, Rio Vista, CA
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
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
Wave Energy Oscillating Water Column (OWC)
Wave Energy The 500 kW LIMPET OWC, New Zealand
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
Wave Energy The 750 kW Pelamis Wave Energy Converter, Portugal
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
Tidal Energy • Gravitational Force • Proportional to Mass of Earth, Moon • Inversely Proportional to Distance Squared Maximum Gravitational Force: High Tide Minimum Gravitational Force
Tidal Energy • Centrifugal Force • Earth-Moon System • “Spinning Through Space” Center of Mass Minimum Centrifugal Force Maximum Centrifugal Force: High Tide
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
Tidal Energy Tidal Barrage at La Rance, France 240 MW Capacity 333 m Long 8 m Tidal Range
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
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
Geothermal Energy Many Possible Configurations Steam Turbine Electricity to Grid Generator Cooling Tower Flash Chamber Heating, Processing
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
Geothermal Energy • Benefits • No Intermittency • Low/Zero Pollutant Emissions • Challenges • Source Depleted (Energy Mining) • 250:1 Use to Recharge Rate • Limited Sources • High Quality Sources Tapped • Most Near Tectonic Plate Interfaces • Better Utilize Low Quality Sources • Ground Source Heat Pump
How do we get Sustainable? • As Citizens • Reduce, Reuse, Recycle • Drive a Fuel Efficient Car • Don’t 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
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
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
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
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.