Energy

1. Chapter 17 Energy

2. 3 Automatic safety devices that shut down the reactor when water and steam levels fall below normal and turbine stops were shut off because engineers didn’t want systems to “spoil” experiment. Figure 17-1Page 350 2 Almost all control rods were removed from the core during experiment. 1 Emergency cooling system was turned off to conduct an experiment. Cooling pond Cooling pond Turbines Turbines Radiation shields Radiation shields Reactor Reactor 5 Reactor power output was lowered too much, making it too difficult to control. Crane for moving fuel rods Steam generator Water pumps 4 Additional water pump to cool reactor was turned on. But with low power output and extra drain on system, water didn’t actually reach reactor.

3. Chernobyl • Effects: • Blew roof off reactor building • Clouds of radioactive material • Premature deaths • Radioactive crops, cattle • Thyroid cancer

4. Energy Sources • 99% of energy comes from the sun • Other 1% comes from commercial energy (nonrenewable) • Commercial energy- burning of fossil fuels • 84% nonrenewable • 16% renewable

5. Figure 17-3aPage 352 Nuclear power 6% Hydropower, geothermal, solar, wind 6% Natural Gas 22% RENEWABLE 16% Biomass 10% Coal 23% Oil 33% NONRENEWABLE 84% World

6. Figure 17-3bPage 352 Nuclear power 8% Hydropower geothermal solar, wind 3% Natural Gas 24% RENEWABLE 6% Coal 23% Oil 39% Biomass 3% NONRENEWABLE 94% United States

7. New Energy Alternatives Would take at least 50 years (+ huge financial investments) to phase in new energy alternatives

8. 7 Questions Concerning New Energy How much of energy resource is available in near & long-term future? Net energy yield? Cost for development, phase in, & use? Government research & development subsidies & tax breaks? How will dependence affect national & global economic & military security? Vulnerable to terrorism? How will extraction, transportation, & use affect environment, human health, & climate?

9. Net Energy Total amount of energy available from resource minus energy needed to find, extract, process, & get resource to consumers Importance- higher net energy ratios make better energy sources Oil- high ratio- comes from large, accessible, & cheap-to-extract deposits Nuclear power- low ratio- requires large amounts of energy input

10. Petroleum Petroleum (crude oil)- thick, gooey liquid consisting of combustible hydrocarbons Extracted- by wells drilled into deposits Refining- heat & distill (separate by boiling points)

11. Petrochemicals Products of oil distillation Pesticides Plastics Synthetic fibers Paints Medicines

12. Oil Reserves Top 5 reserves- Saudi Arabia, Iraq, United Arab Emirates, Kuwait, Iran 2.9% of oil is found in US reserves 26% of oil is used by US 55% of US oil used is imported

13. Oil Supply Global – 80% depleted within 41-93 years US – 10-48 years (2005)

14. Figure 17-14Page 360 Trade-Offs Drilling for Oil and Natural Gas In Alaska’s Arctic National Wildlife Refuge Advantages Disadvantages Only 19% of finding oil equal to what U.S. consumes in 7-24 months Too little potential oil to significantly reduce oil imports Costs too high and potential oil supply too little to lower energy prices Studies show considerable oil spills and other environmental damage from Alaskan oil fields Potential degradation of refuge not worth the risk Unnecessary if improved slant drilling allows oil to be drilled from outside the refuge Could increase U.S oil and natural gas supplies Could reduce oil imports slightly Would bring jobs and oil revenue to Alaska May lower oil prices slightly Oil companies have developed Alaskan Oil fields without significant harm New drilling techniques will leave little environ- mental impact

15. Figure 17-15Page 360 Trade-Offs Conventional Oil Advantages Disadvantages Ample supply for 42-93 years Low cost (with huge subsidies) High net energy yield Easily transported within and between countries Low land use Technology is well developed Efficient distribution system Need to find substitute within 50 years Artifically low price encourages waste and discourages search for alternative Air pollution when burned Releases CO2 when burned Moderate water pollution

16. Figure 17-18Page 362 Trade-Offs Heavy Oils from Oil Shale and Oil Sand Advantages Disadvantages High cost (oil shale) Moderate cost (oil sand) Low net energy yield Large potential supplies, especially oil sands in Canada Large amount of water needed for processing Severe land disruption from surface mining Easily transported within and between countries Water pollution from mining residues Efficient distribution system in place Air pollution when burned Technology is well developed CO2 emissions when burned

17. Natural Gas • Underground deposits of gases • 50-80% methane (by weight) Remaining is propane or methane LPG – liquefied petroleum gas – natural gas mixture of liquefied propane & butane gas LNG – liquefied natural gas – natural gas converted to liquid by cooling to low temperature

18. Natural Gas Reserves • Russia • Iran • Qatar • 3% of reserves found in US • World supply – should last 62-125 years • US supply – 55-80 years

19. Figure 17-19Page 363 Trade-Offs Conventional Natural Gas Advantages Disadvantages Ample supplies (125 years) Nonrenewable resource High net energy yield Releases CO2 when burned Methane (a greenhouse gas) can leak from pipelines Low cost (with huge subsidies) Less air pollution than other fossil fuels Difficult to transfer from one country to another Lower CO2 emissions than other fossil fuels Shipped across ocean as highly explosive LNG Moderate environmental impact Sometimes burned off and wasted at wells because of low price Low land use Easily transported by pipeline Requires pipelines Good fuel for fuel cells and gas turbines

20. Coal • Solid, combustible mixture of organic compounds with 30-98% Carbon by weight • Extraction- underground (subsurface) mining, surface mines • 2 major uses- steel production & electricity

21. Figure 17-20Page 364 Increasing heat and carbon content Increasing moisture content Peat (not a coal) Lignite (brown coal) Bituminous Coal (soft coal) Anthracite (hard coal) Heat Heat Heat Pressure Pressure Pressure Partially decayed plant matter in swamps and bogs; low heat content Low heat content; low sulfur content; limited supplies in most areas Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas

22. Coal Reserves • US, Russia, China • 25% of reserves are in US • World supply- 300 years • US- 300-400 yrs

23. Figure 17-21Page 365 Trade-Offs Coal Advantages Disadvantages Ample supplies (225–900 years) Very high environmental impact Severe land disturbance, air pollution, and water pollution High net energy yield Low cost (with huge subsidies) High land use (including mining) Mining and combustion technology well-developed Severe threat to human health High CO2 emissions when burned Air pollution can be reduced with improved technology (but adds to cost) Releases radioactive particles and mercury into air

24. Figure 17-22Page 365 Trade-Offs Synthetic Fuels Advantages Disadvantages Large potential supply Low to moderate net energy yield Higher cost than coal Vehicle fuel Requires mining 50% more coal High environmental impact Moderate cost (with large government subsidies) Increased surface mining of coal High water use Lower air pollution when burned than coal High CO2 emissions when burned

25. Nuclear Fission Reactor • Isotopes of Uranium & Plutonium are split (chain reaction) • Heat generated produces steam which turns turbine = electricity

26. Light-water Nuclear System (LWR) • Fuel- uranium oxide- stable uranium pellets • Control rods- neutron-absorbing material; regulates fission/power • Moderator- slows neutrons to continue chain rxn (water, graphite) • Coolant- water-circulates through core to remove heat from fuel rods & to produce steam

27. Containment vessel- thick, strong walls; keeps radioactive material from escaping to environment • Water-filled pools (dry casks)- on-site storage for highly radioactive (spent) fuel rods

28. Nuclear Fuel Cycle • Mining uranium • Processing as fuel • Use in reactor • Safely storing wastes • Disposing of reactor

29. Open Nuclear Fuel Cycle • Isotopes are not removed by reprocessing nuclear wastes • Eventually reburied in underground disposal facility

30. Closed Nuclear Fuel Cycle • Fissionable isotopes (Uranium-235 & Plutonium-239) are removed from spent fuel assemblies for reuse as nuclear fuel • Must be stored for 10,000 years

31. Figure 17-24Page 368 Decommissioning of reactor Fuel assemblies Reactor Enrichment UF6 Fuel fabrication Temporary storage of spent fuel assemblies underwater or in dry casks (conversion of enriched UF6 toUO2 and fabrication of fuel assemblies) Uranium 235 as UF6 Plutonium-239 as PuO2 Conversion of U3 O8 to UF6 Spent fuel reprocessing Low level radiation with long half-life Geologic disposal of moderate and high-level radioactive wastes Open fuel cycle today Prospective “closed” end of fuel cycle

32. Nuclear Power Dev. After WW2 • Atomic Energy Commission- promised lower cost for nuclear energy (vs. coal) • Government (taxpayers) paid ¼ cost of building commercial reactors & guaranteed there would be no cost overruns • After insurance companies refused to insure nuclear power, Congress passed Price-Anderson Act to protect US nuclear industry & utilities from significant liability in accidents

33. 7 Factor of Declined Use of NP • Multibillion dollar construction cost overruns • Higher operating costs • More malfunctions than expected • Poor management • Public safety concerns • Stricter government safety regulations • Investor concerns about economic feasibility of nuclear power

34. Figure 17-26Page 370 Trade-Offs Conventional Nuclear Fuel Cycle Advantages Disadvantages Large fuel supply High cost (even with large subsidies) Low environmental impact (without accidents) Low net energy yield High environmental impact (with major accidents) Emits 1/6 as much CO2 as coal Catastrophic accidents can happen (Chernobyl) Moderate land disruption and water pollution (without accidents) No widely acceptable solution for long-term storage of radioactive wastes and decommissioning worn-out plants Moderate land use Low risk of accidents because of multiple safety systems (except in 35 poorly designed and run reactors in former Soviet Union and Eastern Europe) Subject to terrorist attacks Spreads knowledge andtechnology for building nuclear weapons

35. Figure 17-27Page 371 Trade-Offs Coal vs. Nuclear Coal Nuclear Ample supply Ample supply of uranium Low net energy yield High net energy yield Low air pollution (mostly from fuel reprocessing) Very high air pollution High CO2 emissions Low CO2 emissions (mostly from fuel reprocessing) High land disruption from surface mining Much lower land disruption from surface mining High land use Moderate land use Low cost (with huge subsidies) High cost (with huge subsidies)

36. Safety Features • Multiple built-in safety features • 15-45% chance of complete core meltdown in US reactor during the next 20 years • 39 US reactors have 80% chance of failure in containment shell from meltdown or explosion

37. Vulnerable to Terrorist Attack • Plants were not designed to withstand an attack like September 11 • Insufficient security against ground-level attacks

38. Attack on Stored Radioactive Waste • Highly radioactive & thermally hot fuel would be exposed to air & steam • Zirconium outer cover would catch fire • Fire would burn for days • Release significant amount of radioactive material into atmosphere • Large areas contaminated for decades • Economic & psychological havoc

39. Low-Level Waste • Gives off small amounts of ionizing radiation • Must be stored safely for 100-500 years • Placed in steel drums & shipped to 2 regional (state or fed run) landfill • Includes: tools, building materials, clothing, glassware, & other contaminated items

40. High-Level Waste • Bury deep underground • Shoot into space or sun • Bury in Antarctic ice sheet or Greenland ice cap • Dump into subduction zone • Bury in mud deposits in ocean basins • Change into harmless isotopes

41. Yucca Mountain Storage Site +Negligible risks of accident or sabotage of waste shipments -Decrease national security -Many shipments of waste material -Geologic instability

42. Decommissioning of Worn-out Nuclear Power Plants • Dismantle plant & store large volume of highly radioactive materials in high-level nuclear waste storage facility • Physical barrier around plant with full-time security for 30-100 years before dismantling plant • Enclose entire plant in tomb that must last & be monitored for several thousand years

43. Dirty Radioactive Bombs • Explosion & cancers could kill thousands • Spread radioactive material over hundreds of city blocks • Contaminate buildings & soil • Clean-up would cause billions $$ • Intense psychological terror & panic

44. Conventional Nuclear Power + Lower operating costs - Must include total cost

45. Breeder Nuclear Fission + Generate more nuclear fuel than they consume - Failed safety system could result in loss of liquid sodium coolant = combustion in air & explosion in water - Slow process - Cost

46. Nuclear Fusion + No emissions of air pollutants (carbon dioxide) + Infinite fuel source (water) + Less radioactive waste + No risk of meltdown or release of large amounts of radioactive materials + Little risk of bomb-grade materials + Used to destroy toxic waste - Negative energy yield - Cost

47. Government Subsidies For the research & development of conventional nuclear power: • Conventional nuclear power cannot compete in today’s open, decentralized, & unregulated energy market • Should keep nuclear options available for future use