1. Fossil Fuels and the Environment

2. Fossil Fuels Fossil fuels are forms of stored solar energy
Plants convert solar energy to chemical energy through photosynthesis
Incomplete decomposed organic matter then covered up
Converted to oil, natural gas, and coal
Provide 90% of energy consumed

6. Crude Oil and Natural Gas
Most geologist accept the hypothesis that these derived from organic matter
Buried in what are known as depositional basins
Oil and gas primarily found along plate boundaries
Exceptions to this include Texas, Gulf of Mexico and the North Sea

7. Crude Oil and Natural Gas
Source rock is fine grained, organic- rich sediment
At a depth at least 500 m
Subjected to increased heat and pressure that initiates the chemical transformation
Elevated pressure causes sediment to be compressed
This initiates upward migration to lower- pressure reservoir rock

8. Crude Oil and Natural Gas
Reservoir rock is coarser grained and relatively porous
sandstone and porous limestone
Trap
Natural upward migration of the oil and gas is interrupted or blocked
Rock that helps form a trap known as cap rock, often shale

11. Petroleum Production Primary production Enhanced recovery
Involves simply pumping the oil from wells
Recovers only 25% of petroleum in reservoir
Enhanced recovery
Increase the amount recovered to about 60%
Steam, water, or chemicals injected into the reservoir to push oil towards wells

12. Petroleum Production
Next to water, oil is the most abundant fluid in the upper crust
Concentrated in a few fields
Proven oil reserves are the part of the total resource that has been identified and can be extracted now at a profit
Domination of energy use in North America but not reserves.
Leads to trade imbalance

16. Oil in the Twenty-First Century
Recent estimates of proven oil reserves suggest that oil and natural gas will last only a few decades.
When will we reach peak production?
Likely to be between
Will have to adjust to potential changes in lifestyle and economies in a post- petroleum era

17. Oil in the Twenty-First Century
Argument that we are head toward a potential crisis
We are approaching the time when approximately 50% of the total crude oil available from transitional oil fields will have been consumed.
Proven reserves are about 1.2 trillion barrels. World consumption is quickly using what is left.

18. Oil in the Twenty-First Century
For every three barrels of oil we consume, we are finding only one barrel.
Forecasts that predict a decline in production of oil are based on many assumptions but most expert agree it is coming in the next few decades.
In the US production of oil as we know it now will end by World production by 2100.

19. Oil in the Twenty-First Century
Before shortages we need to planning and appropriate action to avoid
Military confrontation
Food shortages
Social disruption
Need to develop alternative energy sources
Solar energy
Wind power
Nuclear power

20. Natural Gas Only begun to utilize this resource
Transported by pipelines
Worldwide estimates of recoverable gas will last about 70 years.
In US about 30 years
Considered a clean fuel
Produces fewer pollutants than burning oil or coal
Could be a transition fuel to alternative energy

21. Coal-Bed Methane
The process of coal formation also produces a lot of methane that is stored within coal
Estimated amount is about five-year supply
Promising energy source however there are several environmental concerns
Disposal of large volumes of salty water
Migration of methane, which may contaminate surrounding areas

22. Coal-Bed Methane Environmental benefits
Produces a lot less carbon dioxide than does burning coal or petroleum.
Reduces the amount of methane released into the atmosphere

23. Methane Hydrates
Beneath the seafloor there exist deposits known as methane hydrates
White, ice like compound made up of molecules of methane gas molecular “cages” of frozen water
Forms as a result of microbial decomposition on the sea floor and then trapped in ice
Also found on land in permafrost

24. Methane Hydrates
Found in ocean where deep, cold seawater provides high pressure and low temperatures.
Not stable at lower pressure and warmer temperatures
Documented cases of releases seen off coast of Norway
Potential energy source but currently no way to mine or transport the gas

25. Environmental Effects of Oil and Natural Gas
Recovery, refining, and use of oil and natural gas cause well documented environmental problems.
Air and water pollution, acid rain, and global warming

26. Recovery Possible environmental impacts on land include:
Use of land to construct pads for wells, pipelines, and storage tanks and to build a network of roads and other production facilities.
Pollution of surface waters and groundwater from: leaks from broken pipes or tanks containing oil or other chemicals and salty water (brine) that is brought to the surface in large volumes with the oil.

27. Recovery
Accidental release of air pollutants, such as hydrocarbons and hydrogen sulfide (a toxic gas).
Land subsidence (sinking) as oil and gas are withdrawn.
Loss or disruption of and damage to fragile ecosystems, such as wetlands or other unique landscapes.

28. Recovery
Environmental impacts associated w/ oil production in marine environment:
Oil seepage into the sea from normal operations or large spills from accidents.
Release of drilling muds containing heavy metals, such as barium, that may be toxic to marine life.
Aesthetic degradation from the presence of offshore oil drilling platforms, which some people think are unsightly.

30. Refining
At refineries, crude oil is heated so that its components can be separated and collected
Fractional distillation
Accidental spills and slow leaks
Over years large amount of hydrocarbons released, polluting soil and ground water
Variety of chemicals used in the industrial process which have the potential to pollute.

31. Air pollution most serious impact associated with use (burning)
Delivery and Use
Crude oil mostly transported on land by pipelines and across the ocean in tankers
Both have danger of oil spill
Air pollution most serious impact associated with use (burning)
Contributes to urban smog

37. Coal
Partially decomposed vegetation, when buried in a sedimentary environment, may be slowly transformed into the solid, brittle, carbonaceous rock.
Most abundant fossil fuel
At current consumption rate could last 250 years

40. Coal Classified according to its energy and sulfur content
Anthracite
Bituminous
Subbituminous
Lignite
Energy content greatest in anthracite and lowest in lignite
Lower sulfur coal emits less sulfur dioxide

43. Coal Mining and the Environment
In US thousands of sq miles disturbed by coal mining
Only about half reclaimed
The process of restoring and improving disturbed land, often by reforming the surface and replanting vegetation.

44. Strip Mining
A surface process in which overlying layers of soil and rock is stripped off to reach the coal.
Over half of the coal in US mined this way
One serious problem is acid mine drainage
The drainage of acidic water from mine sites
Happens in eastern US where there is abundant rain fall

45. Strip Mining
Acid mine drainage occurs where surface water infiltrates spoil banks
Water reacts with sulfide minerals to produce sulfuric acid.
The acid then pollutes streams and groundwater

47. Strip Mining
In arid and semiarid regions the land may be more sensitive to activities related to mining
Exploration and road building
Soils thin and water scarce
Makes reclamation more difficult
Reclamation can minimize damage
Laws vary by site

49. Strip Mining Appalachian Mountain’s of West Virginia
Technique known as “mountaintop removal”
Strip-mining levels tops of mountains and fills valleys w/ mining waste
Flood hazard increases as valleys filled w/ mine waste and toxic waste water is stored behind coal waste sludge dams
Also produces voluminous amounts of coal dust

50. Surface Mining Control Act of 1977
Strip Mining
Surface Mining Control Act of 1977
US government has required that mined land restored to support pre-mining use
Prohibit mining on prime ag land
Reclamation includes
Disposing of wastes
Contouring the land
Replanting vegetation

51. Underground Mining Accounts for 40% of coal mined in the US
Some of the environmental problems:
Acid mine drainage from the mines and waste piles has polluted thousands of kilometers of streams.
Land subsidence can occur over mines.
Coal fires in underground mines may be either naturally caused or deliberately set.

53. Transport of Coal
Transporting coal from mining areas to large population centers where energy is needed.
Significant environmental issue
Freight trains and slurring pipelines have been used

54. The Future of Coal Burning of coal Coal 90% of our energy reserves
produces 60% of electricity used and
25% of total energy consumed in US
Coal 90% of our energy reserves
However coal power plants emit
70% of sulfur dioxide
30% of nitrogen oxides
35% of carbon dioxide

55. The Future of Coal
Clean Air Amendments of 1990 mandate reducing these emissions.
Option for cleaner coal include:
Chemical and/or physical cleaning of coal prior to combustion.
New boiler designs that permit lower temp of combustion.
Injection of material rich in calcium carbonate into the gases following burning.
Scrubbers-removes sulfur dioxides

56. The Future of Coal
Conversion of coal at power plants into gas before burning.
Convert coal to oil.
Consumer education about energy conservation and efficiency to reduce the demand for energy.
Development of zero emissions coal- burning electric power plants

57. The Future of Coal
As oil and gas reserves dry up more pressure put on coal.
Increased use of coal will have significant environmental impact.
More land strip mined.
Burning coal produces large amounts of air pollutants
Handling of large quantities of coal through all stages has potentially adverse environmental effects.
include aesthetic degradation, noise, dust, and release of harmful or toxic trace elements into the water, soil, and air.

58. EPA grants utility companies tradable allowances for polluting
Allowance Trading
EPA grants utility companies tradable allowances for polluting
1 allowance good for 1 ton of sulfur dioxide
Could then be traded and sold by brokers
Idea is to reduced overall pollution through economic market forces

59. Fine grained sedimentary rock containing organic matter (kerogen).
Oil shale
Fine grained sedimentary rock containing organic matter (kerogen).
When heated to 500oC oil shale yields oil
Destructive distillation
The oil from shale called synfuel

60. Tar Sands
Sedimentary rocks or sands impregnated with tar oil, asphalt, or bitumen.
Recovered by mining the sands and then washing the oil out with hot water.
Most in Alberta, Canada
Strip mined
Similar problem as with shale, greater volume

62. Oil shale Recovery done both surface and subsurface
Disposal of waste a problem because shale must be retorted
Volume of waste 20-30% greater than original volume.
Despite this oil shale may developed as oil prices rise.