Nonrenewable Energy Resources

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Chapter 16

• Nonrenewable Energy Resources

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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

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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

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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

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Beep, Beep

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

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Coal
Oil and Natural Gas
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
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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

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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

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Way to go US

• The U.S. is the worlds largest energy consumer
• We use 25 of the worlds energy (even though we
  only have 4.5 of the total population)
• India with 17 of the population only uses 3 of
  the worlds commercial energy
• 91 of the U.S.s energy in nonrenewable

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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

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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

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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

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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

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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

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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

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Ticket to Ride

• Most oil in the US is used for transportation
• Gasoline
• Diesel
• Lubricant oil and grease
• Some as LNG

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Gases
Gasoline
Aviation fuel
Heating oil
Diesel oil
Naphtha
Grease and wax
Furnace
Fig. 14.16, p. 337
Asphalt
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Disadvantages
Advantages
Ample supply for 4293 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
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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

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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

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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

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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
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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

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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

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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
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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?

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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

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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
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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

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Advantages
Disadvantages
Ample supplies (225900 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
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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

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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

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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

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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

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

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Raw coal
Recover sulfur
Air or oxygen
Raw gases
Clean Methane gas
Steam
2C Coal

O2
2CO
Pulverizer
Recycle unreacted carbon (char)
CO

3H2
CH4

H2O
Methane (natural gas)
Slag removal
Pulverized coal
Fig. 14.30, p. 345
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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
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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

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LWR light water reactors

• All US reactors are of this type, so know it

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Small amounts of Radioactive gases
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
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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

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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

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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
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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
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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

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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

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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

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Waste container
Fig. 14.38a, p. 351
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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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And the bad stuff?

• High level radioactive waste must be stored for
  10,000 to 240,000 years until it reaches a safe
  level
• Currently most is stored at the reactor site,
  sealed in drums, in pools of water

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Proposed methods of disposal

• Bury deep underground this is the leading
  strategy currently
• Shoot it into space/Sun
• Bury it deep in the Antarctic ice sheet
• Dump it into descending subduction zones
• Bury in deep mud deposits on ocean floor
• Convert into less harmful isotopes (currently we
  do not have the technology)

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Fig. 14.39a, p. 352
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Radioactive contamination

• The EPA suggests that there are 45,000 sites in
  the US (20,000 belong to the DOE)
• It is expected to cost over 230 billion over the
  next 75 years
• More than 144 highly contaminated weapons
  construction sites will never be completely
  cleaned