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Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege

Engineering 10. Chp.6 Energy EROEI - Nuclear. Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege.edu. EROEI. E nergy R eturned O n E nergy I nvested Energy Invested – in order to: ACQUIRE energy, it TAKES ENERGY To PROCESS (Refine) energy, it TAKES ENERGY

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Bruce Mayer, PE Licensed Electrical & Mechanical Engineer BMayer@ChabotCollege

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  1. Engineering 10 Chp.6 EnergyEROEI - Nuclear Bruce Mayer, PE Licensed Electrical & Mechanical EngineerBMayer@ChabotCollege.edu

  2. EROEI • Energy Returned On Energy Invested • Energy Invested – in order to: • ACQUIRE energy, it TAKES ENERGY • To PROCESS (Refine) energy, it TAKES ENERGY • TRANSPORT a form of energy, it TAKES ENERGY. • STORE energy, it TAKES ENERGY. • USE energy, it also TAKES ENERGY

  3. EROEI • Energy Returned On Energy Invested • Energy Returned: • After you have taken into account all the energy used in the last slide...how MUCH ENERGY do you have left? • OR How much energy does it actually COST in order to USE a particular form of energy?

  4. EROEI - Analogy • Say that you have $100 that you want to INVEST at a bank. • The bank is offers an account for a year that pays 10% interest. • Check the TOTAL Gain or LOSS From this Investment • What if you didn't have a car so you take the Bus to the Bank. It costs you $4 to catch the bus round-trip to go to the bank and deposit the money. • After a year, you pay another $4 to catch another bus to the bank to withdraw your money and interest. • The math on This investment: • $100 + 10% interest = $110 at the end of the year. • MINUS $4 for the first bus and another $4 for the 2nd bus = $8 total. • Subtracting the $8 from the $110 that leaves a total of $102; • the REAL return on your investment = 2/100 = 2% • Not such a good deal after all

  5. EROEI Graphically BackWork Note: EROI ↔ EROEI • If there is NO Surplus, then Eout/Ein <1, and We have WASTED energy

  6. EROEI – Fuel (Thermal) Energy

  7. EROEI – Electrical Energy • From these Lists We Spot a Couple of Dicey Propositions • Solar Electricity • Corn Ethanol as a fuel

  8. EROEI Life Cycle Analysis Example • Consider the Production of a Wind Turbine with a 20-25yr Operating Life

  9. Wind Turbine Nacelle http://www.vestas.com/en/about-vestas/sustainability/wind-turbines-and-the-environment/life-cycle-assessment-(lca).aspx

  10. Turbine Production Environmental NEGATIVE Impacts Manufacturing of raw materials Production of components The wind turbine’s energy production De-commissioning of the wind turbine Wind Turbine LCA

  11. 3.0 MWe Wind Turbine EROEI • Energy Invested = 4,304 MWh/turbine • Energy Returned = 173,580 MWh/turbine • 7,890,000 kWh/Turbine٠Year • 22 Year Operating Life • The EROEI Calculation: • An EXCELLENT Return!

  12. WindPower DownSide • WindPower is NONDispactchable • Can NOT call it up at any time • Needs Supplemental STORAGE

  13. Energy Sources – Fact & Fancy • Question – Which Energy Source Has These Attractive Aspects • NO HydroCarbon or NOx Emissions • NO GreenHouse Gas Emissions • Very High Energy Density • Easy to Transport Fuel • Plug-Compatible With Existing Electrical Grid • Can Easily Produce Hydrogen During “Off Peak” Hours • Low Energy Inputs to Produce?

  14. Answer → Nuclear (Fission) Power

  15. Energy Sources – Fact & Fancy • Nuclear Fission Limitations • Waste Handling is a Political Issue • Have Technological Solutions • Waste Concentration, and Then Storage in Water-Free, Geologically Stable Salt-Mine Structures • Fear of Accidental Radiation Releases Due to Loss of Coolant Accidents Such as TMI • New Designs are Fail-Safe; LoCA’s can Be Engineered OUT • ByProduction of Nuclear-Weapons Compatible Materials; e.g., Plutonium

  16. Energy Sources – Future • Any of the Previous Techniques Could Benefit from Technology “BreakThrus” • Possible Examples • A BioEngineered Fermentation Enzyme Greatly Reduces Energy Required to Make Ethanol • Nuclear FUSION • Fission: Break a Heavy Atom (Uranium) to Liberate Heat (and Neutrons) • FUSION: Combine Light Hydrogen Atoms to Liberate Heat (and Make Heavier Helium Atoms)

  17. Energy Sources – Future cont • Fusion Produces MUCH LESS Radioactive Material Than Fission Reactors • But it’s NOT Zero • Fuel is “Heavy Water” Isotopes That are in More than Sufficient Supply in Sea Water • Fusion Limitations • An EXTREMELY Difficult Technical Problem; Must Generate Local Temperatures That Approximate those found in STARS • 50 Years of Intense Study Have barely Even Reached the Energy Break-Even Point

  18. Fission & Fusion Nuclear Reactions • Fission → Splitting • Fusion → Joining • Dueterium → H with 1 Neutron (2 nucleons) • Tritium → H with 2 Neutrons (3 nucleons)

  19. Electric Cars? • The USA consumes about 140 BILLION Gallons of Gasoline per year • As discussed by Dr. Mike Carnall in his Ethanol presentation • Lets make an estimate of how much electricity would be needed to replace the amount of gasoline used by on-road vehicles

  20. Electricity Estimate Assumptions • 95% of Gasoline is used in Cars/Trucks • Gasoline heat of combustion = 45 MJ/kg • Gasoline Density = 737 kg/cu-m • Piston Engine Thermal efficiency = 25% • Electricity Transmission Efficiency = 96% • Battery charging efficiency = 80% • Battery discharging efficiency = 80% • Electric Motor efficiency = 90% • 1 cubic meter = 264.2 gallon [US, liquid]

  21. Electricity Estimate • 95% of Gasoline used by Vehicles • 133B gallons to Cu-m

  22. Electricity Estimate • Mass of 503M cu-m • Thermal Energy in 371B kg of Gasoline

  23. Electricity Estimate • Energy delivered to DriveShaft using 25% Engine Efficiency • This is the amount of Mechanical Energy that must be delivered to the DriveShaft by the electric motor that REPLACES the gasoline engine • Now Work BACKwards

  24. Electricity Estimate • Electrical Energy applied to the motor using motor efficiency • Energy stored in Batteries to Power the motor using Battery efficiency • Electrical Energy applied to Battery Charger using charger efficiency

  25. Electricity Estimate • Electrical Energy produced at the PowerPlant using Transmission Efficiency • Thus the ADDITIONAL electric energy that power plants must produce to run vehicles is about 7 550 000 TeraJoules in a year

  26. Electricity Estimate • Convert TeraJoules per year into MegaWatts-Electric (MWe) • And a J/s is a watt, so the MWe equivalent:

  27. Electricity Estimate • Now a BIG nuclear PowerPlant such as Diablo Canyon is rated at about 2000 MWe – Use this to Calc the NEW Power Plants needed run vehicles

  28. Electricity Estimate • Thus to Run our vehicles on Electricity we would need to open a NEW Nuclear PowerPlant EVERY MONTH for TEN YEARS

  29. New Electricity for Cars Compared • The TOTAL generating Capacity in the USA is about 1 070 000 MWe • The Electricity for Cars would add about 25% to the USA total • The Total generating Capacity in the CALIFORNIA is about 56 000 MWe • The Electricity for Cars would require about 4 NEW Californias

  30. Energy Summary • In My Humble Opinion ENERGY PRODUCTION is the SINGLE MOST IMPORTANT Technology Issue Facing Human Kind • A Low-Cost, Low-Environmental-Impact Energy Source GREATLY Facilitates The Solution of All Technical Problems • Food Production • Medical Advances • Water Production • Housing & Shelter

  31. All Done for Today Cool Videos https://lasers.llnl.gov/multimedia/video_gallery/ NationalIgnitionFacility Fusion in LIVERMORE

  32. Electricity Estimate • Engery delivered to DriveShaft using 25% Engine Efficiency • Electrical Energy applied to the motor using motor efficiency

  33. DT Reaction

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