Chapter 18

Fossil Fuels and the Environment

Fossil Fuels

Forms of stored solar energy created from incomplete biological decomposition of dead organic matter

Buried (swamp-like environment) and oxidized

• Crude Oil• Natural Gas• Coal

Crude Oil• Crude Oil

– Naturally occurring petroleum, normally pumped from wells in oil fields (primary production)

• secondary production: steam or CO2 injected to push oil up

– Refinement of crude oil produces most of the petroleum products we use today

Natural Gas

• Natural Gas– Naturally occurring

gaseous hydrocarbon generally produced in association with crude oil or from gas wells

– An important efficient and clean burning fuel (cleaner than oil) commonly used in homes and industry

Oil in the 21st Century

• The U.S has an energy problem caused by dependence on fossil fuels, especially oil

• Maximum global production is expected between 2020 and 2050

• The challenge is to plan for the decline in oil supply and shift to alternative energy sources

Methane Hydrates

• White ice-like compound made up of molecules of methane gas

• Trapped in “cages” of frozen water in the sediments of the deep seafloor or within areas of permafrost

• “transitional” fuel source– combustion produces less CO2 than

conventional fossil fuels

• Coal-bed methane

Environmental Effects of Oil and Natural Gas

• Recovery: damage to fragile ecosystems, water and air pollution, land subsidence, and waste disposal

• Refining: soil, water and air pollution• Delivery and Use: energy to power

automobiles, produce electricity, etc.

Arctic National Wildlife Refuge

• Pristine wilderness area in Alaska with large oil reserve

• Favor of:– oil is needed– create jobs– new tools and

drilling practices means less impact

Arctic National Wildlife Refuge

• Against drilling:– should remain as a

wilderness– ice roads require

much water from ponds

– heavy vehicles will scar the open tundra

Coal

• Solid, brittle, carbonaceous rock that is one of the world’s most abundant fossil fuels.

• Classified according to energy content as well as carbon and sulfur content– low sulfur coal emits less sulfur dioxide, so

more desirable– high sulfur coal: acid rain (burned) and acid

mine drainage (water in mines)

Coal Mining and the Environment

• Strip Mining– A surface mining

process in which the

overlying layer of

soil and rock is

stripped off to reach

the coal-acid mine drainage

-erosion

-sediment pollution

• Underground Mining– Associated with environmental problems

including acid mine drainage, land subsidence and coal fires

- spoil piles

- mine collapse

- mine fires

• Transport of Coal– freight trains; coal-slurry pipelines

• The Future of Coal– 90% of fossil fuel reserves– Scrubbing: removes sulfur dioxides; lower

temperature (reduce air pollution)

• Allowance Trading– Reduces pollution– EPA grants utility companies tradable

allowances for polluting

Oil Shale and Tar Sands

• Oil Shale– A fine-grained sedimentary rock– exceeds global reserves of oil– The oil is a synfuel– requires much energy to extract and make

usable; not competitive with cost of crude oil or other conventional fossil fuels

• Tar Sands– Sedimentary rocks or sands impregnated with

tar oil, asphalt or bitumen