1. Coal and Natural Gas

2. NATURAL GAS Natural Gas Liquefied petroleum gas (LPG):
mostly methane (CH4), small amounts of toxic hydrogen sulfide (H2S)
Cleaner burning, less CO2 than other fossil fuels
Hydrogen sulfide smells like rotten eggs, can cause shortness of breath, dizziness, death
Liquefied petroleum gas (LPG):
Propane (C3H8) and butane (C4H10) are liquefied and removed can be used for heating or cooking.
Transported to rural areas not served by Pipelines

3. Methane is a Green House Gas 20 to 24 times more powerful at warming the atmosphere than CO2.
We import some of our natural gas from Canada
Natural gas provides 23% of U.S. energy: 12% for electricity, 52% to heat homes

4. Unconventional Natural Gas
Methane Hydrates:
Methane is trapped in ice under permafrost in the tundra and bottom of the ocean
If it melts and is released, it could
cause underwater landslides/tsunamis
Global Warming

5. Trade-Offs Conventional Natural Gas Advantages Disadvantages
Ample supplies (125 years)
Nonrenewable resource
High net energy yield
Releases CO2 when burned
Low cost (with huge subsidies)
Methane (a greenhouse gas) can leak from pipelines
Less air pollution than other fossil fuels
Lower CO2 emissions than other fossil fuels
Difficult to transfer from one country to another
Moderate environmental impact
Figure 16.11
Trade-offs: advantages and disadvantages of using conventional natural gas as an energy resource. QUESTION: Which single advantage and which single disadvantage do you think are the most important?
Shipped across ocean as highly explosive LNG
Easily transported by pipeline
Sometimes burned off and wasted at wells because of low price
Low land use
Good fuel for fuel cells and gas turbines
Requires pipelines
Fig , p. 368

6. COAL
Formed in several stages as the buried remains of land plants ( mya) were subjected to intense heat and pressure.
Mostly Carbon
small amounts of
Sulfur,
Mercury
radioactive materials
Burned in power plants to produce
62% of World’s Electricity
50% of USA’s Electricity

7. COAL Coal is the most abundant fossil fuel not as versatile as oil
high environmental impact
25% more CO2 than oil
most deadly emission is mercury
Coal also releases more radioactive particles into the atmosphere than nuclear power plants

8. Sulfur dioxide, leads to acid rain
And…
Sulfur dioxide, leads to acid rain
Nitrogen oxides (NOx) released; NO, NO2
These can react further in the atmosphere to produce Ozone (a pollutant).

9. Bituminous (soft coal) Anthracite (hard coal)
Increasing heat and carbon content
Increasing moisture content
Peat (not a coal)
Lignite (brown coal)
Bituminous (soft coal)
Anthracite (hard coal)
Heat
Heat
Heat
Pressure
Pressure
Pressure
Partially decayed plant matter in swamps and bogs; low heat content
Low heat content; low sulfur content; limited supplies in most areas
Extensively used as a fuel because of its high heat content and large supplies; normally has a high sulfur content
Highly desirable fuel because of its high heat content and low sulfur content; supplies are limited in most areas
Figure 16.12
Natural capital: stages in coal formation over millions of years. Peat is a soil material made of moist, partially decomposed organic matter. Lignite and bituminous coal are sedimentary rocks, whereas anthracite is a metamorphic rock (Figure 15-8, p. 343). QUESTION: Are there coal deposits near where you live or go to school?
Fig , p. 368

10. Wash the coal, break it into small pieces, let the sulfur settle out (a little cleaner)
Waste heat
Cooling tower transfers waste heat to atmosphere
Turbine
Coal bunker
Generator
Flue gases
Fly ash
and toxic heavy metals: arsenic
chromium
lead, mercury
Cooling loop
Stack
Pulverizing mill
Condenser
Filter
Figure 16.13
Science: Coal-burning power plant. Heat produced by burning pulverized coal in a furnace boils water to produce steam that spins a turbine to produce electricity. The steam is cooled, condensed, and returned to the furnace for reuse. A large cooling tower transfers waste heat to the troposphere. The largest coal-burning power plant in the United States in Indiana burns 23 metric tons (25 tons) of coal per minute or three 100-car trainloads of coal per day and produces 50% more electric power than the Hoover Dam. QUESTION: Is there a coal-burning power plant near where you live or go to school?
Boiler
Toxic ash disposal
Fig , p. 369

11. About two-thirds of the world's proven coal reserves are found in:
U.S.
China
Russia

12. Even worse than burning coal, is burning culm or waste coal- low energy left-overs from mining
This stuff typically sits out in piles and leaches acids and arsenic into the ground water and rivers. Burning it still produces toxic ash.

13. What else can be done with coal?
Coal can be converted into synthetic natural gas (SNG)
Coal can be converted into liquid fuels (such as methanol or synthetic gasoline)
Drawbacks
Costs are high.
Burning them adds more CO2 to the troposphere than burning coal.
Need a lot of coal (2x more)
Clean Coal?

14. What the Frack?