E&S:Lecture 13

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dante01
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158133
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E&S:Lecture 13
Updated:
2012-06-11 00:27:31
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  1. Grid Power Storage
    • 1.Large-scale energy storage
    • Electrical energy is stored during times when production (from power plants) exceeds consumption and the stores are used at times when consumption exceeds production.
    • Ex. Pumped HydroelectricPower and Compressed Air Energy storage
  2. Intelligent Grids
    • 1.Transport electrical power
    • -use high voltage transmission lines to minimize resistive losses
  3. Supergrids and Hypergrids
    • 1. 1970s, R.Buckminster Fuller proposed linking the world's electrical grids
    • 2.Creation of a worldwide grid is now underway
  4. Penguins vs Hummingbirds
    • 1. Penguins
    • -dont have to fly, can store energy in form of fat
    • -can survive in harsh conditions
    • 2.Hummingbirds
    • -move constantly
    • -need to eat constantly
    • -body can decrease to 65F
  5. Compressed Gas
    • 1.Natural gas or hydrogen fuels
    • 2. viable for motor vehicles
  6. Advantages of Compressed Gas
    • 1.Very low pollution
    • 2.Reduced maintenance
    • 3.Simialr performance
    • 4.Similar cost
  7. Disadvantages of Compressed Gas
    • 1.Gas must be highly compressed, which requires 20% of the energy it contains
    • 2. Tank weight and tank bulk are significant
    • 3. Vehicle range can be limited
    • 4. Refueling infrastructure is limited
    • -best utilized in vehicle fleets
  8. Liquefied Gas products
    • Natural gas is converted to liquid form for ease of storage or transport
    • -1/1000 of the volume
  9. Disadvantages of Liquefied Gas products
    • 1. Significant energy required to liquefy
    • 2. Evaporative loss of gass, contributes to greenhouse effect
    • 3. Enormous energy density is a safety concern
  10. What are the dominant non-fossil fiel mobile energy storage technology?
    Batteries
  11. Hydrogen reaction
    2H2 + O2 =2H2O
  12. Advantages of Hydrogen
    • 1.Specific energy: 142 Mj/kg
    • 2. No carbon
    • 3. No other emissions except water and some hydrogen
  13. Disadvantages of Hydrogen
    • 1. No free hydrogen on Earth
    • 2. Energy storage material, not a net energy
  14. Making Hydrogen
    • 1.Produced from fossil fuels through steam formation with methane
    • -Electrolysis uses electric current to dissociate H2O to form H2 and O2 gas
  15. Energy efficiency of hydrogen electrolysis is
    50%
  16. Fuel cells
    • 1.Work like batteries
    • 2. Import fresh H2 and O2 and expel H2O
    • 3. Provide efficiencies of up to 80%

    *Cost is very high due to the engineering required
  17. Fuel cell vehicles limited by...
    • 1.The need to store hydrogen
    • 2. Require significant energy
  18. Batteries store electrical in the form of....
    chemical energy
  19. Battery composition
    • 1. Voltaic cells
    • -consist of two half-cells
    • 2.One half cell: anode(-)
    • -where postive ions migrate
    • 3. Other half-cell: cathode(+)
    • -where negative ions migrate
  20. How can a battery be charged?
    by forcing a current at a higher voltage in the opposite direction
  21. Reducing or Oxidizing:Lithium vs Chlorine
    • 1. Reducing:donating electrons(Left side of Periodic Table)
    • -Lithium
    • 2.Oxidizing:accepting electrons(Right side of Periodic Table)
    • -Chlorine
  22. Maximum possible voltage of a single battery cell
    5 or 6 volts
  23. The Baghdad battery
    • 1. One of the oldest batteries (2000 years old)
    • 2. Consists of a clay jar with a stopper made of asphalt
    • 3.when filled with vinegar, produces 1.1 volts
    • 4. Probaly used for electroplating gold and silver
  24. Limitations to Battery performance
    • 1. Secondar reactions limit the lifetime
    • 2. High cost for better batteries
    • 3. Structure is many times the mass of the electrochemically active materials
    • 4. Inefficiences in the electrochemical process
  25. High-Tech batteries
    • 1. Nickel-Hydrogen Batteries
    • -Orbiting spacecraft use
    • 2. 18650 form factor; Li-ion cells
    • -TheTesla Roadster electric vehicle uses
    • -375 V, up to 200KW
  26. Yuneec International E430
    • 1. The world's first commericially produce electric aircraft
    • 2. Produced in China
    • 3.Flying time of 3 hours
    • 4. $5 per flight
    • 5. Top speed: 80 mph

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