Nonrenewable Energy Resources

Oil Origin:dead organic matter subjected to high pressure & high temperature Mostly hydrocarbons Most highly used energy source in developed countries

Oil Recovery Primary oil recovery Secondary oil recovery Tertiary oil recovery

Oil Processing Most crude oil is transported by pipeline to a refinery Distillation is used to separate components From heaviest to lightest

Oil Reserves 13 countries of OPEC (organization of petroleum exporting countries) have 67% of world’s reserves

Pros of Conventional Oil Cheap Easily transported Easily extracted High net energy yield

Cons of Conventional Oil Cheap prices have: Encouraged countries to become dependent on oil Encouraged waste Discouraged improvements in efficiency Discouraged switching to other energy sources Pollution Environmental degradation

Shale Oil Oil shale contains kerogen (a mixture of hydrocarbon compounds) Removed by surface or subsurface mining Shale: crushed & heated to vaporize the kerogen Kerogen sent by pipeline to refinery Processed to remove impurities

Cons of Shale Oil Lower net energy yield than conventional oil Requires lots of water Surface mines destroy the environment Water pollution due to leaching from processed shale Subsurface mining is cost prohibitive

Tar Sand Mixture of clay, sand, water, & bitumen (a high-sulfur heavy oil) Removed by surface mining Heated with steam which floats bitumen to the top Bitumen purified into a synthetic fuel Largest deposits are in Alberta, Canada

Cons of Using Heavy Oil from Tar Sand Low net energy yield Requires lots of water Releases lots of air pollutants Processing plants create huge waste disposal ponds

Natural Gas 50-90% methane, other hydrocarbons & H 2 S Conventional N.G. lies on top of crude oil Unconventional N.G. is found in coal beds, shale rock, underground sands & gas hydrates & have promise in the future because of their abundance

World’s Natural Gas Supplies U.S. surpassing Russia as largest natural gas producer (fracking)

Pros of Natural Gas Cheaper than oil High net energy yield Burns hot with less pollution than other fossil fuels Extraction damages the environment less than extracting coal or uranium Easy to process Can be used to power vehicles & in fuel cells

Cons of Natural Gas Some H 2 S & SO 2 can be released during processing Must be converted to liquid form before it can be shipped by tanker Conversion is expensive & dangerous & reduces useful net energy yield by ¼ Leaks of natural gas contribute to global warning(CH 4 ) Fracking Ted Talk: Fracking

Coal Is a solid, rocklike fossil fuel Mostly carbon, some water, & sulfur Three types: Lignite—brown coal, low heat & sulfur content, limited supplies Bituminous—soft coal, most commonly used, high heat content, large supplies, high sulfur Anthracite—hard coal, high heat content, takes longest to form, expensive, low sulfur

Coal Extraction Strip mining Surface mining in which overlying layer of soil & rock stripped off to reach coal Most common method of extraction Environmentally destructive, rain & spoil produces sulfuric acid  water pollution Subsurface mining 40% of U.S. mining Dangerous  accidents, black lung Labor intensive Acid drainage, land subsidence

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How Is Coal Used?

Use of Coal to Generate Energy Pulverized coal is burned at high temperatures Steel pipes containing water run through the fire producing high pressure steam Steam turns a turbine Turbine spins a generator to produce electricity

Coal Supplies 66% of reserves are in the U.S., former Soviet Union, & China

Pros & Cons of Coal Pros Abundant High net energy yield Cons Environmental effects of extraction (erosion, air pollution, water pollution) Extraction is dangerous Dirtiest fossil fuel to burn Expensive to transport

Nuclear Energy Currently 24% of electricity in U.S. Energy created through a controlled nuclear reaction which boils water to power a generator Fuel is nonrenewable & dangerous wastes are created

Nuclear Fission Reactors Split nuclei of atoms of U-235 to release energy in the form of high-energy heat Heat is used to make high-pressure steam Steam spins turbines to generate electricity

Light Water Reactor Parts Core containing fuel rods packed with uranium pellets Control rods which are moved in & out of the core to regulate the rate of fission Moderator keeps chain reaction going (can be water, graphite, or heavy water) Coolant (usually water) circulates through the core to remove heat & produce steam for generation of electricity

Advantages of Nuclear Power No emission of air pollutants 1/6 the CO 2 of coal-generated electricity Water pollution & land disruption are low to moderate Many safeguards in place to prevent accidents

Cons of Nuclear Power Radioactive wastes/spent fuel Can be reprocessed or stored long term (for between 10,000 to 240,000 years) Fuel rods stored in pools of water on site No underground storage facilities have ever been built After 15 to 40 years of operation nuclear plants must be decommissioned

Safety of Nuclear Power Plants 1979 Three Mile Island Partial loss of reactor coolant 50% of core melted & fell to the bottom of the reactor Unknown amounts of radiation escaped NRC estimates a 15-45% chance of a complete meltdown at a U.S. reactor in the next 20 years

What Do We Do With Low- Level Radioactive Waste? Must be stored years Between most was put into steel drums & dumped into the ocean Since 1970 they have been buried in government-run landfills

What Should We Do With High-Level Radioactive Waste? Must be stored for thousands of years Proposals: Bury it underground in earthquake resistant & waterproof areas Shoot it into space or into the sun Bury it under the Antarctic ice sheet or Greenland ice cap Dump it into descending subduction zones in the deep ocean Change it into harmless, or less harmful, isotopes

Contaminated Radioactive Sites in the U.S. 45,000 exist Will cost at least $230 billion & 75 years to clean up

What Can Be Done With Worn-Out Nuclear Plants? Three methods proposed: Immediate dismantling Mothballing for years & then dismantling entombment

Nuclear Reactors & the Spread of Nuclear Weapons Today the U.S. & 14 other countries sell nuclear power technology in the international marketplace We live in a world with enough nuclear weapons to kill everyone on earth 40 times

A Sustainable Energy Future for the U.S. Need individual action Government action: Increase fuel efficiency standards for vehicles Establish energy-efficiency standards for buildings & appliances Increase government sponsored R and D Give tax credits & rebates Tax energy

A Sustainable Energy Future for the U.S.—cont. Rely on more renewable energy Provide subsidies & tax credits Increase R and D Reduce pollution & health risk Cut coal use Phase out coal subsidies Levy taxes on coal & oil use Phase out nuclear power & nuclear power subsidies