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Chapter 16

Chapter 16. Nonrenewable Energy Resources. Energy resources. 99% of energy used to heat the earth and all the buildings comes from the sun The sun also creates renewable energy resources – wind, flowing water, biomass. The rest. The last 1% comes from fuel resources

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Chapter 16

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  1. Chapter 16 Nonrenewable Energy Resources

  2. Energy resources • 99% of energy used to heat the earth and all the buildings comes from the sun • The sun also creates renewable energy resources – wind, flowing water, biomass

  3. The rest • The last 1% comes from fuel resources • Fossil fuels make up the vast majority • Petroleum, coal, and natural gas • A small portion also comes from nuclear sources

  4. Is it getting hot in here? • Which energy source has the highest net energy ratio for space heating? • Passive solar, yes, just letting in sunlight to warm a room is the most efficient • Which energy source has the highest net energy ratio for high-temperature industrial uses? • coal

  5. Beep, Beep • The highest net energy ratio for transportation • Natural gas • Unfortunately, current NG cars have limited driving ranges and limited fueling sites.

  6. Coal seam Oil and Natural Gas Coal Geothermal Energy Hot water storage Contour strip mining Floating oil drilling platform Oil storage Geothermal power plant Oil drilling platform on legs Area strip mining Pipeline Pipeline Oil well Drilling tower Mined coal Gas well Valves Water penetrates down through the rock Pump Underground coal mine Water is heated and brought up as dry steam or wet steam Impervious rock Natural gas Oil Hot rock Water Water Magma Fig. 14.11, p. 332

  7. What is this stuff? • Petroleum is a gooey liquid consisting of primarily hydrocarbons • Also called crude oil (or just oil) • Oil is widely used because it is cheap, easily transported and has a high net energy yield • Through distillation we produce many products - asphalt, heating oil, diesel, gasoline, grease, wax, natural gas

  8. Shifts in energy usage worldwide • During the 20th century • Coal use dropped from 55 to 22% • Oil increased from 2 to 30% • Natural gas rose from 1 to 23% • Nuclear rose from 0 to 6% • Renewable (wood and water ) dropped from 42 to 19%

  9. Way to go US • The U.S. is the world’s largest energy consumer • We use 25% of the world’s energy (even though we only have 4.5% of the total population) • India with 17% of the population only uses 3% of the world’s commercial energy • 91% of the U.S.’s energy in nonrenewable

  10. Energy • Net energy refers to the amount of useful energy minus the energy needed to find, extract, process, concentrate, and transport to the users • Nuclear energy has a low net energy ratio because it is expensive to extract and process uranium, convert it into a fuel, build and operate the plant, and dismantle and deal with radioactive plants and waste

  11. Oil, Oil everywhere and not a drop to drink • Extracted as crude oil or petroleum, a thick liquid consisting of hydrocarbons, and some sulfur, oxygen and nitrogen impurities • Produced from decayed plant and animal material over millions of years

  12. Oil continued • Normally crude oil is not found in underground pools, but is spread out in the pores and cracks within rock deep beneath the ground • Primary recovery – drill a hole and pump out the light weight crude that fills the hole

  13. Oil continued • Secondary recovery – pumping water into the well to force oil out of the pores • The oil and water mixture is separated after pumping • Only about 35% of the oil is removed by primary and secondary recovery

  14. Oil continued • Tertiary recovery – either a heated gas or a liquid detergent is pumped into the well to help remove more oil • Tertiary is expensive

  15. Oil continued • At the refinery oil is converted into petrochemicals and used as a resource to create industrial organic chemicals, pesticides, plastics, synthetic fibers, paints, medicines and more. • OPEC – organization of petroleum exporting countries control 67% of the worlds oil and maintain control over pricing

  16. Ticket to Ride • Most oil in the US is used for transportation • Gasoline • Diesel • Lubricant oil and grease • Some as LNG

  17. Heated crude oil Gases Gasoline Aviation fuel Heating oil Diesel oil Naphtha Grease and wax Furnace Fig. 14.16, p. 337 Asphalt

  18. Disadvantages Advantages Ample supply for 42–93 years Need to find substitute within 50 years Low cost (with huge subsidies) Artificially low price encourages waste and discourages search for alternatives High net energy yield Easily transported within and between countries Air pollution when burned Low land use Releases CO2 when burned Moderate water pollution Fig. 14.21, p. 340

  19. Oil continued • Oil shale is a fine grained sedimentary rock containing solid combustible organic material (waxy hydrocarbons) called kerogen • Shale oil is made from heating oil shale • Tar sand contains bitumen (a high sulfur heavy oil) another combustible organic material • Both are more expensive than crude recovery because it requires more energy, land disruption, and are more difficult to extract, produce roughly the same oil but with lower net energy yield

  20. Oh, Canada • There is a lot of shale oil and tar sands in North America, particularly in Canada. • As the price of crude oil goes up, the value of this heavy oil also goes up and becomes economically profitable to extract. • Unfortunately, almost all vegetation above the reserves must be removed to obtain these resources, so the environmental cost is very high

  21. Domestic Oil • US extraction of oil has decreased since 1985, thus increasing our reliance on other countries • Switching to alternative fuels sources helps maintain our economic independence

  22. Advantages Disadvantages Moderate existing supplies High costs Low net energy yield Large potential supplies Large amount of water needed to process Severe land disruption from surface mining Water pollution from mining residues Air pollution when burned CO2 emissions when burned Fig. 14.25, p. 342

  23. Natural Gas • Mostly CH4 methane with some ethane, propane and butane and small amounts of hydrogen sulfide (toxic) • LPG (liquefied petroleum gas) the propane and butane are removed from natural gas and stored under pressure

  24. How long will it last? • Natural gas should last about 125 years worldwide • About 75 years in the US • Overall about 200-300 years with rising prices, better technology, and more discoveries

  25. Advantages Disadvantages Ample supplies (125 years) Releases CO2 when burned High net energy yield Methane (a greenhouse gas) can leak from pipelines Low cost (with huge subsidies) Shipped across ocean as highly explosive LNG Less air pollution than other fossil fuels Sometimes burned off and wasted at wells because of low price Lower CO2 emissions than other fossil fuels Moderate environ- mental impact Easily transported by pipeline Low land use Good fuel for fuel cells and gas turbines Fig. 14.26, p. 342

  26. The future of power plants • There is currently being developed a combined cycle natural gas electric power plant with 60% efficiency • This is much better than 32-40% efficiency of others (coal, oil, nuke) • What other reasons make it better?

  27. Coal • Solid fuel of combustible carbon, most formed 285-360 million years ago • Peat – 1st, low heat content • Lignite – 2nd, low heat and low sulfur • Bituminous Coal – 3rd, high heat and abundant supply, high sulfur • Anthracite – 4th, high heat, low sulfur, limited supply

  28. 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 Fig. 14.27, p. 344

  29. Coal for energy • Coal provides about 22% of the commercial energy in the world • It is used to create 62% of the worlds electricity • 75% of the worlds steel • China is the largest user followed by US • US creates 52% of energy with coal

  30. 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) Severe threat to human health High CO2 emissions when burned Releases radioactive particles and mercury into air Fig. 14.28, p. 344

  31. The cost of coal • Land disturbance • Air pollution (especially sulfur dioxide) • Co2 emissions • Water pollution • Electricity production (coal) is the second largest producer of toxic emissions • The most deadly emission is mercury

  32. Wonderful coal • 60,000 babies annually are born with brain damage due to mercury exposure, typically from pregnant mothers eating mercury in fish • Coal also releases more radioactive particles into the atmosphere than nuclear power plants • Also, acid rain and methane release

  33. Coal in the US • Air pollutants kill thousands (estimates are from 60,000 – 200,000) • Cause at least 50,000 cases of respiratory disease • Cost several billion dollars in property damage

  34. The good news • Fluidized bed combustion is reducing the amount of pollution • Hot air is blown under a mix of crushed limestone and coal while it is burnt • This removes most sulfur dioxide, reduces Nox and burns the coal more efficiently and cheaply

  35. Flue gases Coal Limestone Steam Fluidized bed Water Air nozzles Air Calcium sulfate and ash Fig. 14.29, p. 345

  36. Coal gasification • Solid coal can be converted into synthetic natural gas (SNG) • It can also be made into synfuels (liquids) through coal liquefaction • Neither is expected to play a major role in our future energy needs

  37. Remove dust, tar, water, sulfur Raw coal Recover sulfur Air or oxygen Clean Methane gas Raw gases Steam + O2 2CO 2C Coal Pulverizer Recycle unreacted carbon (char) CO + 3H2 CH4 + H2O Methane (natural gas) Slag removal Pulverized coal Fig. 14.30, p. 345

  38. Advantages Disadvantages Large potential supply Low to moderate net energy yield Higher cost than coal Vehicle fuel High environmental impact Increased surface mining of coal High water use Higher CO2 emissions than coal Fig. 14.31, p. 346

  39. Nuclear Energy • Uranium 235 and plutonium 239 are split (nucleus) to release energy • The reaction rate is controlled • The energy heats water and turns it to steam • Steam spins turbines connected to generators which create electricity

  40. LWR light water reactors • All US reactors are of this type, so know it

  41. Small amounts of Radioactive gases Uranium fuel input (reactor core) Containment shell Emergency core Cooling system Control rods Heat exchanger Hot coolant Hot coolant Coolant Coolant Moderator Coolant passage Pressure vessel Shielding Waste heat Electrical power Steam Useful energy 25 to 30% Generator Turbine Hot water output Condenser Pump Pump Cool water input Black Pump Waste heat Water Waste heat Water source (river, lake, ocean) Periodic removal and storage of radioactive wastes and spent fuel assemblies Periodic removal and storage of radioactive liquid wastes Fig. 14.32, p. 346

  42. Nuclear is out of favor (unless you ask Bush) • The US has not ordered a new nuclear facility since 1978, and 120 ordered since 1973 were cancelled • Most countries are phasing out nuclear plants or are not continuing to expand their programs, except China who is trying to move away from dependence on coal

  43. Why is nuclear not meeting expectations? • Multi-billion dollar cost of construction • Strict govt. safety regulations • High operating costs • More malfunctions than expected • Poor management • Public concern after Chernobyl, and Three Mile Island • Investor concern about economic feasibility

  44. 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 Moderate land disruption and water pollution (without accidents) Catastrophic accidents can happen (Chernobyl) No 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) Spreads knowledge and technology for building nuclear weapons Fig. 14.35, p. 349

  45. Coal Nuclear Ample supply Ample supply of uranium High net energy yield Low net energy yield Low air pollution (mostly from fuel reprocessing) Very high air pollution High CO2 emissions Low CO2 emissions (mostly from fuel reprocessing) 65,000 to 200,000 deaths per year in U.S. About 6,000 deaths per year in U.S. 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) Fig. 14.36, p. 349

  46. Chernobyl • In the former Soviet Union, April 26, 1986 the reactor core went out of control and exploded sending a cloud of radioactive dust into the atmosphere • 3,576 – 32,000 people died • 400,000 forced to evacuate • 62,000 square miles still contaminated • More than 500,000 people exposed to high level radiation • Cost the govt. $385 billion

  47. Three Mile Island • March 29, 1979 in Harrisburg, Penn. • Coolant failed and core melted • Radioactive material escaped into air • 50,000 people evacuated • Luckily the radiation release was believed to be too low to cause death or cancer • Cleanup has cost $1.2 billion so far

  48. What do we do with the waste? • Low level radioactive waste must be stored for 100-500 years until it reaches a safe level (does not give off harmful ionizing radiation) • This was done by sealing the waste in steel drums and dumping it in the ocean • Today some countries (US) stores the waste at govt. run landfills, but no one wants to live anywhere near them

  49. Waste container 2 meters wide 2–5 meters high Several steel drums holding waste Steel wall Steel wall Lead shielding Fig. 14.38a, p. 351

  50. Up to 60 deep trenches dug into clay. As many as 20 flatbed trucks deliver waste containers daily. Barrels are stacked and surrounded with sand. Covering is mounded to aid rain runoff. Clay bottom Fig. 14.38b, p. 351

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