2Fossil Fuels Fossil fuels are forms of stored solar energy Plants convert solar energy to chemical energy through photosynthesisIncomplete decomposed organic matter then covered upConverted to oil, natural gas, and coalProvide 90% of energy consumed
6Crude Oil and Natural Gas Most geologist accept the hypothesis that these derived from organic matterBuried in what are known as depositional basinsOil and gas primarily found along plate boundariesExceptions to this include Texas, Gulf of Mexico and the North Sea
7Crude Oil and Natural Gas Source rock is fine grained, organic- rich sedimentAt a depth at least 500 mSubjected to increased heat and pressure that initiates the chemical transformationElevated pressure causes sediment to be compressedThis initiates upward migration to lower- pressure reservoir rock
8Crude Oil and Natural Gas Reservoir rock is coarser grained and relatively poroussandstone and porous limestoneTrapNatural upward migration of the oil and gas is interrupted or blockedRock that helps form a trap known as cap rock, often shale
11Petroleum Production Primary production Enhanced recovery Involves simply pumping the oil from wellsRecovers only 25% of petroleum in reservoirEnhanced recoveryIncrease the amount recovered to about 60%Steam, water, or chemicals injected into the reservoir to push oil towards wells
12Petroleum ProductionNext to water, oil is the most abundant fluid in the upper crustConcentrated in a few fieldsProven oil reserves are the part of the total resource that has been identified and can be extracted now at a profitDomination of energy use in North America but not reserves.Leads to trade imbalance
16Oil 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 betweenWill have to adjust to potential changes in lifestyle and economies in a post- petroleum era
17Oil in the Twenty-First Century Argument that we are head toward a potential crisisWe 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.
18Oil 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.
19Oil in the Twenty-First Century Before shortages we need to planning and appropriate action to avoidMilitary confrontationFood shortagesSocial disruptionNeed to develop alternative energy sourcesSolar energyWind powerNuclear power
20Natural Gas Only begun to utilize this resource Transported by pipelinesWorldwide estimates of recoverable gas will last about 70 years.In US about 30 yearsConsidered a clean fuelProduces fewer pollutants than burning oil or coalCould be a transition fuel to alternative energy
21Coal-Bed MethaneThe process of coal formation also produces a lot of methane that is stored within coalEstimated amount is about five-year supplyPromising energy source however there are several environmental concernsDisposal of large volumes of salty waterMigration of methane, which may contaminate surrounding areas
22Coal-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
23Methane HydratesBeneath the seafloor there exist deposits known as methane hydratesWhite, ice like compound made up of molecules of methane gas molecular “cages” of frozen waterForms as a result of microbial decomposition on the sea floor and then trapped in iceAlso found on land in permafrost
24Methane HydratesFound in ocean where deep, cold seawater provides high pressure and low temperatures.Not stable at lower pressure and warmer temperaturesDocumented cases of releases seen off coast of NorwayPotential energy source but currently no way to mine or transport the gas
25Environmental 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
26Recovery 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.
27RecoveryAccidental 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.
28RecoveryEnvironmental 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.
30RefiningAt refineries, crude oil is heated so that its components can be separated and collectedFractional distillationAccidental spills and slow leaksOver years large amount of hydrocarbons released, polluting soil and ground waterVariety of chemicals used in the industrial process which have the potential to pollute.
31Air pollution most serious impact associated with use (burning) Delivery and UseCrude oil mostly transported on land by pipelines and across the ocean in tankersBoth have danger of oil spillAir pollution most serious impact associated with use (burning)Contributes to urban smog
37CoalPartially decomposed vegetation, when buried in a sedimentary environment, may be slowly transformed into the solid, brittle, carbonaceous rock.Most abundant fossil fuelAt current consumption rate could last 250 years
40Coal Classified according to its energy and sulfur content AnthraciteBituminousSubbituminousLigniteEnergy content greatest in anthracite and lowest in ligniteLower sulfur coal emits less sulfur dioxide
43Coal Mining and the Environment In US thousands of sq miles disturbed by coal miningOnly about half reclaimedThe process of restoring and improving disturbed land, often by reforming the surface and replanting vegetation.
44Strip MiningA 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 wayOne serious problem is acid mine drainageThe drainage of acidic water from mine sitesHappens in eastern US where there is abundant rain fall
45Strip MiningAcid mine drainage occurs where surface water infiltrates spoil banksWater reacts with sulfide minerals to produce sulfuric acid.The acid then pollutes streams and groundwater
47Strip MiningIn arid and semiarid regions the land may be more sensitive to activities related to miningExploration and road buildingSoils thin and water scarceMakes reclamation more difficultReclamation can minimize damageLaws vary by site
49Strip Mining Appalachian Mountain’s of West Virginia Technique known as “mountaintop removal”Strip-mining levels tops of mountains and fills valleys w/ mining wasteFlood hazard increases as valleys filled w/ mine waste and toxic waste water is stored behind coal waste sludge damsAlso produces voluminous amounts of coal dust
50Surface Mining Control Act of 1977 Strip MiningSurface Mining Control Act of 1977US government has required that mined land restored to support pre-mining useProhibit mining on prime ag landReclamation includesDisposing of wastesContouring the landReplanting vegetation
51Underground 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.
53Transport of CoalTransporting coal from mining areas to large population centers where energy is needed.Significant environmental issueFreight trains and slurring pipelines have been used
54The Future of Coal Burning of coal Coal 90% of our energy reserves produces 60% of electricity used and25% of total energy consumed in USCoal 90% of our energy reservesHowever coal power plants emit70% of sulfur dioxide30% of nitrogen oxides35% of carbon dioxide
55The Future of CoalClean 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
56The Future of CoalConversion 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
57The Future of CoalAs 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 pollutantsHandling 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.
58EPA grants utility companies tradable allowances for polluting Allowance TradingEPA grants utility companies tradable allowances for polluting1 allowance good for 1 ton of sulfur dioxideCould then be traded and sold by brokersIdea is to reduced overall pollution through economic market forces
59Fine grained sedimentary rock containing organic matter (kerogen). Oil shaleFine grained sedimentary rock containing organic matter (kerogen).When heated to 500oC oil shale yields oilDestructive distillationThe oil from shale called synfuel
60Tar SandsSedimentary 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, CanadaStrip minedSimilar problem as with shale, greater volume
62Oil shale Recovery done both surface and subsurface Disposal of waste a problem because shale must be retortedVolume of waste 20-30% greater than original volume.Despite this oil shale may developed as oil prices rise.