Ch 10, 11, 12

20% of the world’s population lives in highly developed countries in 2000, these people used 60% of the commercial energy consumed worldwide.

That means…

Each person in highly developed countries uses approximately eight times as much energy as each person in developing countries.

DEVELOPING◦ Farmers rely on their own physical energy or animal

energy.◦ Goal of Developing Countries: improve the standard

of living.◦ Boost economic development?◦ Will be followed by a rise in per-capita energy

consumption.

DEVELOPED◦High-energy input

Fertilizers, machinery, pesticides, etc.◦Makes the agricultural productivity higher!◦Developed nations have a more stable

population, so per-capita energy consumption may be close to saturation.

Must increase energy Must increase energy efficiency!!!efficiency!!!

Partially decayed remnants of organisms formed millions of years ago.

NONRENEWABLE!!! Formation:

◦ COAL: Swamp plants died and fell into the water, which

slowed their decay (little O2) Layers of sediment piled on top Pressure formed carbon-rich coal between layers of

sedimentary rock.

◦ OIL: Microscopic aquatic organisms died & settled to

bottom. Their decay lowered the O2, further slowing decay. Formed hydrocarbon mixture called Oil.

◦ NATURAL GAS: Same way as Oil, only at higher temperatures.

4 types:◦ Lignite, Sub-Bituminous, Bituminous,

Anthracite◦ How do the following change:

Color? Water content? Sulfur Content? Carbon Content? Avg. Heat Value (BTU/Pound)? Cost?

Coal Reserves Worldwide

Surface mines can have substantial effects on the environment◦ Large open pits or trenches◦ Acid and toxic mineral drainage◦ Dangerous landslides

Restorations were half hearted

SMCRA requires coal companies to restore areas. Reclamation begins during the mining process, not after mining ends

Brainstorm!!!

Safety issues:◦ Mine collapses, disease

(Black Lung)

Environmental Issues:◦ Land disruption (open pit mines, mountain top

removal), acid mine drainage, increased erosion, sediment pollution in streams, landslides

◦ Air emissions (CO2, Sulfur&Nitrogen oxides, acid deposition – and acidification of lakes/streams)

SCRUBBERS◦ Recall: uses mist of water to remove precipitates◦ Can sell the sludge to manufacturers:

Sludge can make: Wallboard, soil conditioner Fly Ash an make: lightweight concrete

CLEAN COAL TECHNOLOGIES◦ 1 – Fluidized-Bed Combustion

Mix crushed coal w/ limestone & O2 at low temps. Produces fewer nitrogen oxides Produces NO sulfur oxides (sulfur mixes with the

limestone)◦ 2 – Coal Gasification

Mix crushed coal w/ steam & air to produce CH4 & CO2! Sulfur is naturally removed, so no scrubbers are

needed.NOTE: “Clean Coal” isn’t perfect –

still have CO2 released!

Petroleum / Crude Oil ◦ Hundreds of hydrocarbon

compounds

◦ How is it created??? Microscopic aquatic organisms

don’t decay much. Sediment piles on top, and they become oil!

◦ How are they separated? Based on boiling points! Fractional Distillation

How Oil & Natural gas form… They migrate upward (low density) and are

trapped by impermeable rock layers.

OIL: mostly in the Persian Gulf

NATURAL GAS: mostly in Russia & Iran

ALSO: Much

may be found in the cont.

shelf!

Difficult to say…◦ Oil production will peak between 2010 & 2020.

◦ Improving tech will allow us to extract more & produce oil from natural gas, coal & synfuels.

Then the oil peak will move to 2050 – 2100

Dependence of the United States and other countries on Middle Eastern oil has potential international security

implications as well as economic impacts.

Burning (combustion), obtaining fuels (production & transport)◦ Increased carbon dioxide emissions

Every gallon of gas releases 20lb. of carbon dioxide

◦ Acid deposition (Nox)

Natural Gas does not pollute as much as oil◦ Relatively clean, efficient source with almost no S◦ Produces less CO2, fewer hydrocarbons and few

particulate matter

Supertanker hit Bligh Reef Spilled 10.9 million gallons of crude into Prince

William Sound, Alaska Killed a LOT of wildlife

◦ 30,000 birds (ducks, loons, cormorants, eagles)◦ 3,500- 5,000 sea otters◦ Killer whale & harbor seal population disrupted◦ Salmon migration disrupted◦ No fishing for the year in the area

Cleaned the area using mechanized steam cleaning and rinsing (killed shoreline organisms)

Cost estimated at 10 billion OIL POLLUTION ACT (1990)

Established liability for damages to natural resources resulting from spills

Requires double hulls on all oil tankers that enter US waters.

250 mill gallons of crude were dumped into the Persian Gulf (6x that of Exxon).

Oil wells were set on fire & lakes of oil spilled into the desert

Initial cleanup efforts hampered by the war.

1980 NE Alaska declared wilderness area. ~7.7 B barrels of oil within the refuge Bush supports opening refuge to drilling.

◦ Senate voted against development 2002.◦ Continues to be debated today in congress.

Conservationists believe that oil exploration posed permanent threats to the delicate balance of nature in the Alaskan wilderness.

Synfuels “Synthetic Fuels” Derived from coal & other natural sources

◦ Liquid or gaseous◦ Include:

Tar sands Oil shales Gas hydrates Liquefied coal Coal gas

Remember: They’re alternatives, but they’re not perfect!!!

…Lots of CO2 emissions!

Synfuels: Tar Sands aka “Oil Sands” Sand deposits permeated with thick oil called

bitumen. Must be heated underground to make it fluid

enough to pump. Must be refined like crude oil Lots of it!

◦ (1/2 again as much fuel as world oil reserves) Reserves in Venezuela & Canada

Synfuels: Oil Shales Rocks containing a mixture of hydrocarbons

called kerogen. Must be crushed & heated, and kerogen must be

refined. Not yet cost efficient, although there’s lot of it! Reserves in Australia, Estonia, Brazil, Sweden,

USA, China

Synfuels – Gas Hydrates aka “Methane Hydrates” Ice-encrusted natural gas Deposits in

◦ Arctic Tundra (deep below permafrost)◦ Deep ocean sediments

Expensive to mine Reserves in Russia

Synfuels Coal Liquefaction

◦ Nonalcoholic liquid (similar to oil)

◦ Produced from coal◦ Less polluting than solid

coal◦ Too expensive now

Coal Gasification◦ Produce combustible

methane◦ C + H2O CH4 + CO2

◦ Burns almost as cleanly as natural gas

US Energy Policy!1. Increase energy efficiency & conservation

Low $ encourages high consumption… should we increase the price??

Gov’t Subsidies reduce the price to stimulate the economy Gov’t Taxes increase the price to generate revenue

Which is better???

2. Secure future fossil fuel energy supplies Only a temporary strategy…

3. Develop alternative energy sources Gasoline tax may help this…

4. Accomplish the first three objectives without further damaging the Environment Duh!!

Remember… Policies change every

4-8 years

NUCLEAR ENERGY Energy released in combustion reactions

comes from changes in the chemical bonds that hold the atom together.

Nuclear Energy involves changes within the nuclei of the atom. Small amounts of matter from the nucleus are converted into large amounts of energy

Fission: Larger atoms of certain elements are split into smaller atoms of certain elements. Power Plants.

Fusion: 2 smaller atoms are combined to make 1 large atom of a different element. Mass of the end product is less than the mass of the starting materials released as energy. The Sun.

The AtomNeutron

Proton

Electron

Atomic Number: # of protons

Atomic Mass: # of protons + # of neutrons

Nucleus

Isotope: forms of a given element with different numbers of neutrons therefore different atomic masses.

ex) Hydrogen has 1 P and no N

Deuterium has 1 P and 1 N

Tritium has 1 P and 2 N

As a radioactive element emits radiation, its nucleus changes into the nucleus of a different element that is more stable…. Radioactive decay.

Each radioisotope has its own characteristic rate of decay.◦ Half-Life: the period of time required for one half

of the total amount of a radioactive substance to change into a different material. Iodine- 131 0.02 years ( 8.1 days) Krypton-85 10.4 years Plutonium- 239 24,400 years

Uranium ◦ U-235: produces a fission chain reaction

Critical mass: amount of U-235 required to start a chain reaction

Less than 1% of all uranium is U-235 Known as enriched uranium

URANIUM & PLUTONIUM◦ U-235: produces a fission chain reaction

Critical mass: amount of U-235 required to start a chain reaction

Less than 1% of all uranium is U-235 Known as enriched uranium Half life: 700 million years

◦ U-238 Most common (99.3%) Half life of 4.5 billion years When hit by a neutron it decays into PU-239

◦ PU-239 Produced in breeder reactors from U-238 Half life of 24,000 years Regulated by international inspections because it

can be used in nuclear weapons.

Nuclear Fuel Cycle

1. Mining2. Enrichment

(refining process)

3. Fuel rods4. Fuel assemblies

(200 rods) 5. Reactor

(~ 250 fuel assemblies)

6. Fuel is used7. Fuel is reprocessed8. Fuel is disposed of or

sent for enrichment.

Uranium Fission: U-235 is bombarded with neutrons and

absorbs a neutron becoming unstable and splits into 2 smaller atoms.

Two or 3 neutrons are ejected and collide with other U-235 causing a chain reaction.

This releases an enormous amount of heat steam

ENERGY!!!

How is electricity produced??1. Reactor core- heat produced by nuclear fission is

used to produce steam from liquid water.2. Steam generator- uses steam turn a turbine3. Turbine- generates electricity from steam4. Condenser- cools the steam converting it back to a

liquid.

Above each reactor core is a control rod made of metal alloy capable of absorbing neutrons.

The plant will move this up and down depending on the energy needs throughout the day.

Nuclear Power Plant

SAFETY…The reactor is surrounded by a huge steel pot like structure called a reactor vessel. Reactor vessel & steam generator are placed in a containment building.

Three Water Circuits1. Primary water circuit (orange in fig 11.5)

◦ Heats water using energy produced by the fission rxn.◦ Circulates water under high pressure through the core◦ Superheated water cannot expand stays liquid.

2. Secondary Water Circuit (blue in fig 11.5)◦ Convert the water to steam

3. Tertiary Water Circuit (green in fig 11.5)◦ Provides cool water to the condenser cooling off spent

steam in the secondary water circuit.◦ Water moves to a cooling tower or lake.

Breeder Nuclear Fission Uranium is mostly U-238 (not fissionable) U-238 is converted to Plutonium (Pu-239) which

is fissionable Some neutrons emitted are used to produce

additional plutonium from U-238.A breeder reactor makes more A breeder reactor makes more fissionable fuel than it uses!!!!fissionable fuel than it uses!!!!

Since breeder reactors can use U-238, it has the potential to generate much larger quantity of energy from uranium than traditional nuclear

fission.Old waste from plants in the form of U-238 could

be used as fuel.

Breeder Reaction

Is Nuclear Energy Cleaner? Supporters say nuclear energy is better than

alternatives because it is less polluting and more economical and its fuel is plentiful.◦ Spent fuel & wastes are the only major concerns.

Opponents refute these arguments.◦ We should look at clean coal options◦ Nuclear does not significantly lessen GW b/c only

15% of greenhouse gasses are produced by plant.◦ Uranium mining requires the combustion of fossil

fuels.

Cost of Nuclear Power 104 nuclear power plants supply about 23% of

US electricity.

The US has not ordered a nuclear power plant since 1976. ◦ High cost◦ Take years to plan & build◦ Nuclear regulatory process is cumbersome & expensive.

Nuclear Regulatory Commission must oversee all steps in planning and building each site.

SAFETY in Nuclear Power Plants MELTDOWN = at high temperatures, the metal

that encases the uranium fuel melts, releasing radiation.◦ Also, the water used in a nuclear reactor can boil away,

releasing radiation into the atmosphere.

Two case studies:◦ THREE MILE ISLAND (Eastern Pennsylvania)◦ CHORNOBYL (Former USSR – now Ukraine)

Three Mile Island, PA -1979 Result of human error after cooling system failed. 50% meltdown Containment building kept almost all

radioactivity from escaping No substantial environmental damages and no

immediate human casualties◦ After 10 years, the only human health problem was

increased stress. Increased public wariness, and caused new

safety regulations to be enacted.

Chornobyl, USSR -1986 1 or 2 explosions destroyed the nuclear reactor Only 100% meltdown in world history Radiation quickly spread across Europe Human effects:

◦ Many firefighters containing the fire later died◦ 170,000 people had to permanently abandon their

homes◦ Death toll (as of 1999) was almost 170,000◦ Nearly 400,000 adults and over 1 million children

currently receive government aid for health problems Thyroid Cancer, leukemia, immune problems, birth

defects…◦ Soil/farmland was severely damaged

Chornobyl, USSR -cont What happened??

◦ Design of the reactor was flawed no containment unit & unstable at low power This type of reactor (RBMK) is not used in North America or

Western Europe (too unsafe) Adjacent countries still use it!

◦ Human error Many plant operators had no training!

How was it fixed??◦ Entombed the destroyed reactor in a “sarcophagus”

Recent inspections have revealed safety hazards◦ Numerous cracks in the sarcophagus◦ $$$ to fix it – international donors are helping out.

Aftermath…

Chornobyl gets a dome!

Link to Nuclear Weapons Spent Fuel Rods from nuclear energy reactors

can be used to make bombs Storing it is a nightmare (security issue)

◦ Only a few kilograms are needed to make a bomb as strong as the Nagasaki/Hiroshima bombs

Russian Political instability makes us nervous…◦ Former USSR has enough highly enriched uranium and

plutonium to make 40,000 nuclear bombs.◦ Big push in the international community to help Russia

maintain nuclear security. IRAN- Do you watch the news?!?! US plans to get rid of over 50 tons of surplus

plutonium from dismantling our warheads.◦ Will be converted to MOX (mixed oxide), then burned as

fuel in commercial power reactors.

NEW U.S. NUCLEAR POLICY as of 4-12-10

The United States will not employ nuclear weapons against non-nuclear nations that are Non-Proliferation Treaty (NPT) signatories in

good standing.

IRAN: The U.S. and other nations contend that Iran has violated the treaty's terms by pursuing

atomic weapons, an accusation Iran denies.

RUSSIA: What has happened to their arsenal of weapons from the cold war??

OUTCOME OF THE SUMMIT TO BE DETERMINED…

Radioactive Wastes Low-Level radioactive wastes

◦ Give off small amounts of ionizing radiation◦ Produced by nuclear power plants, research labs,

hospitals, and industries.◦ Low Level Radioactive Policy Act (1980)

All states are responsible for the waste they generate. High-Level radioactive wastes

◦ Initially give off large amounts of ionizing radiation◦ Produced by reactor metals (fuel rods and assemblies),

coolant fluids, and gases in the reactor.◦ FUEL RODS:

Absorb neutrons and form radioisotopes Only used for ~3years Storage nightmare…………………

Storage of Nuclear Waste Best bet is stable, underground rock formations. Vitrification:

◦ solidifying liquid waste into solid glass or ceramic logs.

◦ Stored underground. SC (Savannah River) & NY (West Valley)

YUCCA MOUNTAIN◦ Nuclear Waste Policy Act (1982)

Waste disposal is gov’t responsibility.◦ Yucca Mountain (Nevada) was chosen as

the only candidate for perm. disposal. Problems:

◦ Near a volcano & many earthquakes◦ Could contaminate groundwater

-NIMBY and NIMTOO

Renewable Energy and Conservation

Chapter 12

CHAPTER 12 CLASS ASSIGNMENT You will be assigned a group

◦ FOR HOMEWORK, YOU WILL READ YOUR ASSIGNED SECTION (TOPIC) IN THE TEXT & TAKE NOTES Notes will be checked for credit! Bring in any supplies you may need to make a presentation to

the class on your topic Each person in the group must have one GOOD multiple choice

question ready to hand in on their assigned topic next class.

NEXT CLASS: You will have 1/4 to 1/3 of a period to put your thoughts together on your assigned topic

Presentations on each topic should be about 7- 10 min each with question period following

QUIZQUIZ ON ALL PRESENTATIONS ON ALL PRESENTATIONS THE FOLLOWING CLASSTHE FOLLOWING CLASS