Assuming no action is taken to reduce these emissions, the U.S. will emit approximately 8,000 million metric tons (8,800 million tons) of CO2 by 2030, increasing 2005 emission levels by more than 33 percent 86% of the emission will be for power generation

Clean CoalScrubbers and electrostatic precipitaorsLow Nox burnersCrushing and washing coalFluidized bed Capture and sequester CO2

Reducing emissions Soot: Electrostatic precipitators, along with baghouses (which work

like large industrial-scale vacuum cleaners to capture ash and dust particles in felt or woven fabric bags), have been able to reduce the release of soot-forming particulate matter by 99 percent or more. Today, all coal burning power plants employ one, or in some cases, both of these devices

SO2: Scrubbers can reduce sulfur emissions by 90 percent or more. They are essentially large towers in which aqueous mixtures of lime or limestone “sorbents” are sprayed through the flue gases exiting a coal boiler. The lime/limestone absorbs the sulfur from the flue gas.

NOx: Exhaust gases, prior to going up the smokestack, pass through the system where anhydrous ammonia reacts with the NOx and converts it to harmless nitrogen and water.

Mercury: activated carbon – a powdery substance commonly used to remove odors and contaminants in drinking water systems – has also been shown to be effective in absorbing mercury from the flue gases of coal plants

Fluidized-bed combustors

Fluidized bed combustion Blowing pulverized particles of coal into a

super-hot (approx. 3,000 degrees F) combustion chamber – fluidized-bed combustors suspend larger chunks of coal (about the size of your fingernail) on upward-blowing jets of air. 

The bed material consists of a coal-water fuel paste, coal ash, and a dolomite or limestone sorbent.

Dolomite or limestone in the bed reacts with sulfur to form calcium sulfate, a dry, granular bed-ash material, which is easily disposed of or is usable as a by-product.

A low bed-temperature of about 1,600°F limits NOx formation.

 effective in reducing SO2 and Nox by more than 90%

eliminate the need for a post-combustion scrubber, and they can burn almost any grade of coal.

More than 170 fluidized-bed combustion units now operate in the United States.

From 1980 to 2003, the amount of coal

used to generate electricity in the United States increased by 75 percent;

sulfur dioxide, nitrogen oxide and mercury emissions declined by 40 percent

CO2 sequestrationCarbon sequestration encompasses the

processes of capture and storage of CO2 that would otherwise reside in the atmosphere for long periods of time. Geologic sequestrationTerrestrial sequestration

Geologic sequestration is defined as the placement of CO2 into an

underground repository in such a way that it will remain permanently stored.(1) mature oil and natural gas reservoirs,(2) deep unmineable coal seams, (3) deep saline formations, (4) oil- and gas-rich organic shales, and (5) basalt formations.

Deep Saline Formations

Deep unmineable coalseams

Mature oil and natural gas fields

Terrestrial sequestration involves the net removal of CO2 from the atmosphere by plants and microorganisms and its storage in vegetative biomass and in soils. •Also provides ancillary benefits such as habitat and water quality improvements•increasing carbon uptake through reforestation and amendment of minelands and other damaged soils. •through various land management techniques including no-till farming and wetland restoration.

The Coal Plant of the Future Coal gasification (Synthetic Natural Gas – SNG)

 reacting coal with steam and oxygen under high pressures – produces a gas can be cleaned of more than 99% of its sulfur and nitrogen and remove

Mercury and other potential pollutants the coal gas can be cleaned to purity levels approaching, or, surpassing

those of natural gas.  Integrated gasification combined-cycle: like natural gas, cleaned,

the coal gases are burned in a gas turbine-generator to produce electricity. 

Exhaust gases exiting the turbine are hot enough to boil water, creating steam that drives a steam turbine-generator, producing a second source of electricity.

Integrated gasification combined-cycle power plants are one of the cleanest and most efficient coal-fueled power stations. eliminate virtually all of coal's pollutants, generate considerably more power from a given quantity of coal. 60%

against 33-35% of today's power plants Higher coal-to-electricity efficiencies mean that less coal is used to generate

power hence less carbon dioxide is emitted.

SNG: problemsRequire 50% more coalProduces 50% more CO2Costlier

Natural GasUS proven reserve: 164 trillion cubic feetSupplies 25% of all energy consumed in

USConsumption: 22 trillion cubic feet /yearWorld reserve: <5000 trillion cubic feetFormer USSR and Iran account for more

than 60% of world reserveCleanest Fossil Fuel: Emits 30% less CO2

than oil and 43% less than coal, mostly free of sulfur and NO.

Enhanced RecoveryAny dramatic rise in reserves unlikelyTypically about 2/3rd of all oil deposits are left

in the ground because of difficulty of recoveryMethods used for Enhanced recovery include:

Water and CO2 under high pressure and explosives to increase permeability

Hot water and detergents to decrease viscosityCan increase yield by an additional 40%Can be used for old and new fieldsIncreases risks of pollution and ground

subsidenceAdds to the cost

Alternate Gas sourcesGeopressurized gas: At very great depths oil

breaks down to natural gases which dissolves in pore waters and can be recovered by drilling. Est. Reserve: 150 to 2000 trillion cu. ft

Gas Hydrates: In arctic regions and in marine sediments crystalline solids of gas and water called hydrates occur in commercial quantities. Estimated reserve: 10,000 trillion cubic feet (2 X Fossil Fuel reserve) Potential greenhouse effect of methane

Enhanced recovery by fracturing of ‘tight’ sandstones and gas bearing shale in the Appalachians

Oil shaleSedimentary rocks containing kerogen: a waxy

substance formed from the remains of plant, algae and bacteria.

Oil Shale has to be powdered and distilled to recover “oil”

US reserve=2 to 5 trillion barrels = 2/3rd of World supply.

Enough oil to supply USA for 110 yearsFound in Green River Formation of CO,WY and UTWorld supply = 240X crude oil1 ton of oil = 3 tons of rock and 3 barrels of water, Problem of water, waste disposal and land reclamation

Retorting is the process by which oil is recovered from oil shale by application of heat

Tar SandSedimentary rocks containing semi-solid tar-like petroleum

(Bitumen) Either early stage of oil formation or residues after lighter fraction has migrated

away Too thick to be pumped out

Athabasca Tar Sands of Canada may contain 280-300 billion barrels of recoverable oil (total reserve may be more than 2000 billion barrels). Canada hopes to meet 1/3rd of their oil needs from the tar sands.

15% of world’s oil supply, second only to Saudi Arabia. Venezuela other major country with huge tar sand deposit

Uses natural gas and water, produces 80 kg of greenhouse gas each barrel of oil, destroys boreal forests, bogs, rivers

Same processing and disposal problem as oil shale1 barrel of oil uses up 0.7 barrels of energy

Athabasca tar sand