Nonrenewable Energy Resources

Oil

Origin:dead organic matter subjected to high pressure & high temperatureMostly hydrocarbonsMost highly used energy

source in developed countries

Oil Recovery

Primary oil recoverySecondary oil recoveryTertiary oil recovery

Oil ProcessingMost crude oil is transported by pipeline to a refineryDistillation 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

CheapEasily transportedEasily extractedHigh net energy yield

Cons of Conventional OilCheap prices have: Encouraged countries to become

dependent on oil Encouraged waste Discouraged improvements in

efficiency Discouraged switching to other energy

sources

PollutionEnvironmental degradation

Shale OilOil shale contains kerogen (a mixture of hydrocarbon compounds)Removed by surface or subsurface miningShale: crushed & heated to vaporize the kerogenKerogen sent by pipeline to refineryProcessed to remove impurities

Cons of Shale OilLower net energy yield than conventional oil Requires lots of waterSurface mines destroy the environmentWater pollution due to leaching from processed shaleSubsurface mining is cost prohibitive

Tar Sand

Mixture of clay, sand, water, & bitumen (a high-sulfur heavy oil)Removed by surface miningHeated with steam which floats bitumen to the topBitumen purified into a synthetic fuelLargest deposits are in Alberta, Canada

Cons of Using Heavy Oil from Tar Sand

Low net energy yield Requires lots of waterReleases lots of air pollutantsProcessing plants create huge waste disposal ponds

Natural Gas50-90% methane, other hydrocarbons & H2SConventional N.G. lies on top of crude oilUnconventional 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 GasCheaper than oilHigh net energy yieldBurns hot with less pollution than other fossil fuelsExtraction damages the environment less than extracting coal or uraniumEasy to processCan be used to power vehicles & in fuel cells

Cons of Natural Gas

Some H2S & SO2 can be released during processingMust be converted to liquid form before it can be shipped by tankerConversion is expensive & dangerous & reduces useful net energy yield by ¼Leaks of natural gas contribute to global warning(CH4)FrackingTed Talk: Fracking

CoalIs a solid, rocklike fossil fuelMostly carbon, some water, & sulfurThree 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 ExtractionStrip 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 acidwater pollution

Subsurface mining 40% of U.S. mining Dangerousaccidents, black lung Labor intensive Acid drainage, land subsidence

Mountaintop Removal

http://www.youtube.com/watch?v=ZDAFQjLoxCM

How Is Coal Used?

Use of Coal to Generate Energy

Pulverized coal is burned at high temperaturesSteel pipes containing water run through the fire producing high pressure steamSteam turns a turbineTurbine spins a generator to produce electricity

Coal Supplies

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

Pros & Cons of CoalPros 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 generatorFuel 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 heatHeat is used to make high-pressure steamSteam spins turbines to generate electricity

Light Water Reactor Parts

Core containing fuel rods packed with uranium pelletsControl 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 pollutants1/6 the CO2 of coal-generated electricityWater pollution & land disruption are low to moderateMany 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 builtAfter 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 100-500 yearsBetween 1940-1970 most was put into steel drums & dumped into the oceanSince 1970 they have been buried in government-run landfills

What Should We Do With High-Level Radioactive Waste?

Must be stored for thousands of yearsProposals: 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 existWill 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 30-100 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 marketplaceWe 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 actionGovernment 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