1. Environmental Science
Chapter 17: Lecture Notes
Nonrenewable Energy

2. Chapter 17.1 Targets I can list the 3 types of fossil fuels.
I can explain how fuels are used to generate electricity in an electric power plant.
I can explain how each type of fossil fuel formed and how each is collected and used.
I can compare the advantages and disadvantages of fossil-fuel use.
I can list three factors that influence predictions of fossil-fuel production.

3. Energy Resources and Fossil Fuels
Fossil fuels are central to life in modern societies
2 main problems with fossil fuels:
Limited supply
Collecting and using them have environmental consequences
In 21st century, societies will continue to explore alternatives to fossil fuels but will also focus on developing more efficient ways to use these fuels

4. Energy Resources and Fossil Fuels
3 Major Types: Coal, Oil and Natural Gas.
Formed hundreds of millions of years ago before the time of dinosaurs  “fossil” fuels
Formed in Carboniferous Period (part of Paleozoic Era)

5. How Is Electricity Generated
Coal Power Plant Video

6. Energy Use in the United States
U.S. uses more energy per person than any other country except Canada and United Arab Emirates
U.S. uses most energy for industry & transportation

7. Coal Formation
Formed from remains of plants that lived in swamps hundreds of millions of years ago
As ocean levels rose and fell, swamps were covered with sediment
Layers of sediment compressed dead plants; heat and pressure in Earth’s crust caused coal to form
Most coal in U.S formed million years ago
Coal Formation Animation

8. Coal Make up most of world’s fossil-fuel reserves
Relatively inexpensive and needs little refining after being mined
Asia and North America are richest in coal deposits

9. Coal Hard, black rock-like substance
Made of carbon, hydrogen, oxygen, nitrogen and varying amounts of sulfur
Main types of coal:
Anthracite  hardest, produces most energy when burned
Bituminous  between anthracite and lignite
Lignite  softest, does not produce much heat
Peat  still used in many countries as an energy source

10. Charcoal vs. Coal
Charcoal is not a rock or even a type of coal. It is actually wood! Charcoal is created by heating wood to high temperatures in absence of oxygen.

11. Coal Mining and Transport
Found in most lower 48 states of U.S.
2 Main Mining Methods:
Mines dug by sinking shafts deep underground, miners travel by elevators or trains deep underground to dig coal
Strip mines use steam shovels to strip away top layers above coal, layers then restored (RECLAMED)
-2/3 U.S. Coal removed by strip mining (Surface Mining Control and Reclamation Act of 1977)
Coal shipped by train/boats or in pipelines
In pipelines, coal is ground up and mixed with water to make “slurry”
Slurry then pumped through pipelines
Coal Mining Video

12. Coal Use 70% burned to produce electricity
Rest used to make steel or burned in manufacturing
Produces more air pollution than other fossil fuels

13. Air Pollution and Coal Use
Higher-grade coals produce more heat and less pollution than lower-grade coal
Sulfur, in all coal, is major source of pollution when burned
Causes air pollution and acid precipitation
However, clean-burning coal technology has reduced air pollution in U.S.

14. Crude Oil or Petroleum
Formed from diatoms (photosynthetic protists the size of a pinhead)
Diatoms died & fell to sea floor (1)
They were buried under sediment and rock (2). The rock compressed their bodies. The carbon eventually turned into oil under great pressure and heat.
As earth moved and folded, pockets with oil and natural gas were formed (3)

15. Petroleum Oil Collection and Transport
Native Americans used blankets to skim oil off streams and lakes. They used oil as medicine and to waterproof canoes.
Demand for oil increased as a fuel for lamps. It replaced whale oil in lamps because it was cheap. During this time, most petroleum oil came from distilling coal into a liquid or by skimming it off of lakes - just as Native Americans did.
On August 27, 1859, Edwin L. Drake struck liquid oil at his well near Titusville, Pennsylvania. The well pumped the oil into wooden barrels.
This method of oil drilling is still being used today all over the world.

16. Oil and natural gas found underground between folds of rock
To find oil and natural gas, companies drill to deposits deep below the earth’s surface
Oil and natural gas then pumped from below ground by oil rigs
Oil and gas then travel through pipelines or ships
Modern-day oil prospectors use sound waves to locate oil. In one technique, (1) a signal is sent into the rock by a vibrator truck, (2) the reflected waves are received by geophones, and (3) the data is transmitted to a laboratory truck.
Alaska's Oil Video

17. Refineries
Oil Refining Animation
Crude oil stored in large tanks (44 gallons) until sent to oil refineries, where it is split into various products by heating it.
Thousands of products come from oil (almost all plastic comes originally from oil)
Other products include gasoline, diesel fuel, jet fuel, home heating oil, oil for ships and oil to burn in power plants to make electricity.
Refinery Animation

18. OIL USE 63% in U.S. for transportation 25% used in industry
9% for heating
3% for generating electricity
Releases pollutants when burned
contribute to smog and cause health problems
Many scientists think CO2 released from burning oil contributes to global warming
Oil spills from tanker ships are another environmental problem of oil use
While oil spills are dramatic, much more oil pollution comes from everyday sources, like leaking cars

19. Predicting Oil Production
Many different factors must be considered when predicting oil production
Oil reserves: oil deposits that are discovered and are in commercial production
In contrast, some oil deposits are yet to be discovered or to become commercial

20. Future Oil Reserves
No large oil reserves have been discovered in past decade
Additional oil reserves exist under ocean, but it is expensive to drill for oil in deep ocean
Currently, oil platforms can be built to drill for oil in the ocean, but much of the oil in the deep ocean is currently inaccessible

21. Natural Gas
Natural gas seeps first seen in Iran, first ignited by lightning
Lighter than air; mostly methane
Chemical formula is CH4 : one atom of carbon with four atoms hydrogen
Highly flammable
Usually found near petroleum underground; pumped from below ground and travels in pipelines to storage areas
Usually has no odor and you can't see it. Before it is sent to pipelines and storage tanks, it is mixed with a chemical that gives a strong odor. The odor makes it easy to smell if there is a leak.

22. Natural Gas
About 20% of world’s nonrenewable energy comes from natural gas
41% is used in residential/commercial heating
41% is used in industry
15% is used to generate electricity
3% is used for transportation
ADVANTAGE: produces least amount of air pollution of fossil fuels and burns the hottest
DISADVANTAGE: least available of all fossil fuels

23. Fossil Fuels and the Future
Fossil fuels supply ~90% energy used in developed countries
As demand for energy resources increases, cost of fossil fuels will likely increase
This will make other energy sources more attractive
Planning for energy we will use in the future is important because it takes many years for a new source of energy to make a significant contribution to our energy supply

24. Chapter 17.2 Targets Calculate atomic mass.
Define and identify an isotope.
Define radioactivity and describe the 3 radioactive particles.
Define half-life and solve basic half-life problems.
Describe nuclear fission.
Describe the parts of a nuclear power plant and how it produces electricity.
List three advantages and three disadvantages of nuclear energy.
Describe nuclear fusion and its advantages and disadvantages.

25. Nuclear energy = energy trapped inside an atom
Nuclear energy first introduced in 1945; two fission bombs were used against Japan
Today, nuclear power accounts for 17% of the world’s electricity.
Little Boy
Fat Man

26. QUICK REVIEW ATOMSNUCLEUSPROTONSNEUTRONSELECTRONSELEMENTS
Do you know what this # means? 

27. ISOTOPES In most atoms . . . # Protons = # Neutrons
# of Protons in an atom = Atomic Number
Neutrons + Protons = Atomic Mass
Isotopes: atoms with same number of protons BUT a different number of neutrons
EXAMPLE: Carbon-12 and Carbon-16
How many protons and neutrons would each atom contain?

28. *Atomic (Proton) Number *Atomic Mass
*Neutron Number

29. Most isotopes of atoms are stable, sometimes this is not the case:
Radium (the name of the atom is radium, its atomic mass is 226)
The nucleus of Radium-226 is unstable – it will break down and release energy and atomic sub-particles 
This is known as RADIOACTIVITY
When radium atom breaks down (decays), a sub-atomic particle flies out of nucleus at a high speed. This releases energy.
Isotopes try to decay to more stable isotopes.

30. When They Decay, Atoms Emit One of the Following:
1. Alpha Particles = 2 protons + 2 neutrons
(He-4 nucleus)
Travel only a few inches through air and can easily be stopped with a sheet of paper
2. Beta Particles: electrons
Can travel a few feet through air and can be stopped with a few sheets of aluminum foil
3. Gamma Rays: high frequency photons (electromagnetic wave)
Able to travel many meters in air and many centimeters in human tissue. It readily penetrates most materials and is sometimes called "penetrating radiation."

31. The half-life of an isotope is the amount of time it takes for half of the atoms to decay into a more stable form.
Naturally abundant isotopes exist around us because their half-lives are longer than the age of the earth.

32. EXAMPLES:
Uranium 238 (238U) has a half-life of 4.5 billion years so it is naturally abundant.
Most isotopes have short half-lives and must be produced in the laboratory to study or use.
Cobalt-60 (Co-60) has a half-life of 5.3 years and is made in a reactor. Co-60 is used for radiation therapy of cancer patients.

33. PROBLEMS 1. How can you tell if you have an isotope?
See Periodic Table of Elements
Check Atomic Mass
If different than Periodic Table, you have an isotope
EX: Is Calcium-35 an isotope? If so, of what atom is it an isotope?
2. How many protons and neutrons does Calcium-35 contain?
Check Atomic Number
Subtract Atomic Number from Atomic Mass
3. An isotope of cesium (cesium-137) has a half-life of 30 years.  If 1.0 mg of cesium-137 decays over a period of 90 years, how many mg of cesium-137 would remain?
Amount left  =  Original amount ( 1/2)n
n = the number of half-lives 

34. Fission: Splitting Atoms
Nuclear power plants get their power from nuclear energy
Nuclear energy: energy released by a fission or fusion reaction; represents the energy holding an atom’s nucleus together
forces holding together a nucleus of an atom are more than 1 million times stronger than chemical bonds between atoms
In nuclear power plants, atoms of the element uranium are used as the fuel
Uranium is used because it will easily split

35. Fission: Splitting Atoms
Nuclei of uranium atoms are bombarded with neutrons
These collisions cause the nuclei to split in a process called nuclear fission
Nuclear fission releases a tremendous amount of energy and more neutrons then collide with more uranium nuclei

36. How Nuclear Energy Works
Heat released during nuclear reactions is used to generate electricity in the same way that power plants burn fossil fuels to generate electricity.
The energy released from fission reactions heats a closed loop of water that heats another body of water.
As the water boils, it produces steam that drives a turbine, which is used to generate electricity.

37. Reactor Core and Vessel
The main components of the reactor core are:
uranium fuel assemblies
control rods
a coolant /moderator
reactor core contained in the reactor vessel

38. Reactor : Uranium Fuel Assemblies
Uranium-235  fuel pellets (size of pencil eraser)
Fuel pellets stacked inside hollow metal tubes  fuel rods.  Fuel rods are 11 to 25 feet in length.  (Before it is used in the reactor, the uranium fuel is not very radioactive)
Fuel rods are bound together  fuel assemblies (each can contain over 200 fuel rods)

39. Reactor : Control Rods
When a uranium-235 atom absorbs a neutron and splits (fission), it releases energy, and two or more neutrons from its nucleus. 
Chain Reaction: released neutrons from one reaction hit other uranium atoms causing them to fission. 

40. Control Rods
Control speed of nuclear chain reaction, by sliding up and down between the fuel rods in the reactor core. 
Act like sponges to absorb extra neutrons.
To maintain a controlled nuclear chain reaction, the control rods are adjusted so each fission will result in just one neutron (the other neutrons are absorbed by the control rods).
Temperature changes in core are carefully measured. 
If there is a sudden increase in temperature, the reactor immediately shuts down by dropping all control rods into the core, absorbing neutrons.  This shutdown takes only a few seconds.

41. Reactor : Coolant / Moderator
In the U.S., the coolant is water. 
A moderator slows down ("moderates") neutrons (NOT THE SAME AS CONTROL RODS!)
In U.S. nuclear power plants, the moderator is also water (or graphite)
Water slows down neutrons, allowing enough neutrons to be captured by the uranium to cause a chain reaction. 
Just as it is easier to catch a ball that is thrown softly, neutrons are more likely to be captured and cause fission when they are not moving too fast.

42. Pressure Vessel
Protects reactor core; made of carbon steel.  Its walls are 9 inches thick, and it weighs more than 300 tons. 

43. Cooling Towers
Laws prohibit power plants to return hot water directly to a river, ocean, or lake.  For this reason, cooling water in the third loop is pumped to a cooling tower to have some of its heat removed. 
Water is cooled to about 75oF and collected at the bottom of the cooling tower.  Some is returned to the source, but most is used again.

44. How Nuclear Energy Works
Nuclear Power Plant Animation

45. Nuclear Power Advantages and Disadvantages
1. Very little fuel (uranium) needed
2. Fuel has a low cost
3. Water vapor is the only significant emission from nuclear power plants (non-polluting)
4. High electricity output
1. High initial construction costs
2. High operating and maintenance costs
3. Mining and purifying uranium is not a very clean process
4. Improperly functioning nuclear plants can lead to devastating disasters (ex. Meltdowns, Nuclear Power = “Zero-infinity Dilemma”)
5. Spent fuel from nuclear power plants is toxic for centuries and there is no safe/permanent storage area for it

46. Storing Waste
The greatest disadvantage of nuclear power is the difficulty in finding a safe place to store nuclear waste.
The fission products produced can remain dangerously radioactive for thousands of years.
Storage sites for nuclear wastes must be located in areas that are geologically stable for tens of thousands of years.
Scientists are researching a process called transmutation, that would recycle the radioactive elements in nuclear fuel.

47. The Future of Nuclear Power
One possible future energy source is nuclear fusion.
Nuclear fusion: the combination of nuclei of small atoms to form a larger nucleus. Fusion releases tremendous amounts of energy.
It is potentially a safer energy source than nuclear fission is because it creates less dangerous radioactive byproducts.

48. The Future of Nuclear Power
For fusion to occur, three things must occur simultaneously:
Atomic nuclei must be heated to extremely high temperatures (about 100,000,000ºC or 180,000,000ºF)
Scientists have not been able to contain a fusion reaction long enough to get a net energy gain
The nuclei must be properly confined
Technical problems are so complex that building a nuclear fusion plant may take decades or may never happen