Chapter 11

Fossil Fuels

I. Energy Sources and Consumption

• A. Energy sources that were used were obtained locally and now they are worldwide – Fossil fuels

– Nuclear energy

– Electricity

• B. Energy consumption is different between developing and developed nations – 20% of world’s population use 60% of the world’s

energy sources

• C. Energy density

– Amount of energy contained in a given volume or mass of an energy source

• D. Energy efficiency

– A measure of the fraction of energy used relative to the total energy available in a given source

• E. Per capita energy consumption of selected developed and developing countries

Energy Consumption in the US

• YOU NEED TO KNOW TABLE 11.1 on page 229!

II. US Energy Policy

• A. Objective 1: Increase Energy Efficiency and Conservation

– Requires many unpopular decisions

– Examples

• Decrease speed limit to conserve fuel

• Eliminate government subsidies

• B. Objective 2: Secure Future Fossil Fuel Energy Supplies

– 2 oppositions: environmental and economic

• C. Objective 3: Develop Alternative Energy Sources

– Who should pay for this? Gas taxes?

• D. Objective 4: Meet the First Three Objectives Without Further Damage to the Environment

– Example – 5 cent tax on each barrel of domestically produced oil or ton of domestically produced coal to establish a reclamation fund for some of the environmental damage caused by drilling or mining, production, and refining

III. Fossil Fuels

• A. Combustible deposits in the Earth’s crust

– Composed of the remnants (fossils) of prehistoric organisms that existed millions of years ago

– Includes coal, oil (petroleum) and natural gas

• B. Non-renewable resource

– Fossil fuels are created too slowly to replace the reserves we use

IV. How Are Fossil Fuels Formed?

• A. 300 million years ago

– Climate was mild

– Vast swamps covered much of the land

– Dead plant material decayed slowly in the swamp environment

• B. Coal

– Heat, pressure and time turned the plant material into carbon-rich rock (coal)

• C. Oil

– Sediment deposited over microscopic plants

– Heat pressure and time turned them into hydrocarbons (oil)

• D. Natural Gas

– Formed the same way as oil, but at temperatures higher than 100 °C

V. Coal

• A. Most, if not all, coal deposits have been identified

• B. Occurs in different grades - based on variations in heat and pressure during burial

• C. US has 25% of world’s coal supplies

• D. Known coal deposits could last 200 years

– At present rate of consumption

• E. Two Types of Coal Mining

– 1. Surface mining (right)

• Chosen if coal is within 30m of surface – 60%

– 2. Subsurface mining

• Extraction of mineral and energy resources from deep underground deposits – 40%

• F. Environmental Impacts of Mining Coal

– 1. Surface Mining Control and Reclamation Act (SMCRA) (1977)

• Requires filling (reclaiming) of surface mines after mining

• Reduces Acid Mine Drainage

• Requires permits and inspections of active coal mining sights

• Prohibits coal mining in sensitive areas

Mountain Top Removal

• G. Environmental Impacts of Burning Coal

– 1. Releases large quantities of CO2 into atmosphere • Greenhouse gas

– 2. Releases other pollutants into atmosphere • Mercury

• Sulfur oxides

• Nitrogen oxides

– 3. Can cause acid precipitation

• H. Making Coal Cleaner

– 1. Scrubbers

– 2. Fluidized Bed Combustion (below) – mixes crushed coal with particles of limestone in a strong air current during combustion

• Lower temp. and fewer nitrogen oxides are produced – sulfur reacts with the calcium in the limestone so scrubbers are not needed

VI. Oil and Natural Gas

• A. Oil and gas provide 60% of world’s energy

– They provide 62% of US’s energy

• B. Petroleum Refining

– 1. Numerous hydrocarbons present in crude oil (petroleum) are separated

• Based on boiling point

– 2. Natural gas contains far fewer hydrocarbons than crude oil

• Methane, ethane, propane and butane

• C. Oil and Natural Gas Exploration

– 1. Oil and natural gas migrate upwards until they hit impermeable rock

– 2. Usually located in structural traps

• D. Oil Reserves

– 1. Uneven distribution globally

– 2. More than half is located in the Middle East

• E. Natural Gas Reserves

– 1. Uneven distribution globally

– 2. More than half is located in Russia and Iran

Locating more deposits

Future extraction technologies

Changes in global consumption rates

3. Experts indicate there may be shortages in 21st century

• F. How long will supplies last?

– 1. Difficult to determine and estimates vary

– 2. Depends on:

• G. Environmental Impacts of Oil and Natural Gas

– 1. Combustion

• Increase carbon dioxide and pollutant emissions

• Natural gas is far cleaner burning than oil

– 2. Production

• Disturbance to land and habitat

– 3. Transport

• Spills - especially in aquatic systems

• Ex: Alaskan Oil Spill (1989)

1989 Alaskan Oil Spill

1989 Alaskan Oil Spill

• H. 1989 Alaskan Oil Spill

– Exxon Valdez hit a reef and spilled 260,000 barrels of crude oil into sound

– Second largest oil spill in US history

– Led to Oil Pollution Act of 1990

• I. Gulf Oil Spill – April 22, 2010

– Worst spill in US History and worst accidental oil spill in the world’s history

– 206 million gallons were released

– Deepwater Horizon rig had a gas explosion – 11 people were killed

– Oil gushed for 85 days before a cap could be placed on the well - oil covered 572 miles of Gulf shoreline

– 1.82 million gallons of dispersant were used – unknown effects on humans

13 worst oils spills in history

J. Case Study – ANWR – A national wildlife refuge in Alaska

• 1. 1960 – Congress declared a section of northeastern Alaska protected because of its distinctive wildlife

• 2. 1980 – Congress expanded this wilderness area to form the Arctic National Wildlife Refuge (ANWR)

• 3. the Department of the Interior was given permission to determine the potential for oil discoveries in this area, but exploration and development could proceed only with congressional approval

• 4. 1990’s – pressure to open the refuge to oil development – 1994 the US imported more than 50% of their oil – concluded that oil drilling would harm the ecosystem but the Senate and House of Representatives passed measures to allow it but President Clinton vetoed the bill

• 5. 2001 – President George W. Bush announced his support for opening the refuge to drilling but after many debates, the Senate voted against doing so

• 6. still continues to be a debate that plays heavily in Presidential elections

• 7. Pros and Cons

– Pros – economic

– Cons – habitat damage

K. Fracking – Hydraulic Fracturing

• 1. Process - After a well is drilled, the casing is perforated, typically with explosive charges. A “pad” of fluids is then injected, at a sufficient pressure and rate, to fracture the formation surrounding the perforations. The fractured formations are typically located thousands are feet below the water table. Next, producers inject a “slurry,” which consists of fracking fluids and sand, to extend and develop the fracture.

Fracking Process

• 2. Economic Benefits to Fracking

– a. Development of a domestic energy resource (reducing foreign influences on price).

– b. Creation of jobs.

– c. Financial gains to individuals who lease their property to the natural gas companies.

• 3. Environmental Drawbacks of Fracking – a. Habitat fragmentation/destruction can occur from setting up the drilling site

or from building roads.

– b. Earthquakes can result from the drilling/fracking process.

– c. Methane can leak (into the atmosphere) during the process, resulting in an increase of greenhouse gases.

– d. Subsidence of the land can occur once fracking fluids are removed.

– e. Trucks and drilling equipment consume a nonrenewable fuel and release CO2 (greenhouse gases) and, potentially, SOx (which produce acid rain) and NOx (which produce acid rain and photochemical smog).

– f. Noise pollution is caused by the drilling rigs and by increased truck traffic.

– g. Soil salinization or heavy metal contamination can result from the spraying of wastewater.

– h. The drilling site increases the amount of particulate matter in the air.

• 4. Water Related Environmental Problems of Fracking

– a. Ground water contamination • (1) Fracking liquids or chemicals can contaminate drinking water or

groundwater.

• (2) Liquid waste stored in waste lagoons can leach into groundwater (aquifer).

• (3) Drilling can allow methane (or natural gas) to seep into groundwater.

• (4) Leaks from the well casings can contaminate the water with either fracking liquids or flowback liquids.

• (5) Radioactive isotopes used as tracers in fracking fluids can contaminate groundwater.

– b. Surface water contamination

• (1) Brine (or wastewater) sprayed on roadways can run off and contaminate rivers, streams, and lakes.

• (2) Spills of brine (or wastewater) can contaminate rivers, streams, and lakes.

• (3) Wastewater disposed of in streams and rivers may contain salts, heavy metals, benzene, and/or other components of fracking liquid.

• c. Excessive water use or consumption

– (1) Considerable amounts of water are used in the fracking process. This can result in overdrafts of aquifers.

– (2) Water demands for the fracking process compete with water demands for drinking or irrigation (agriculture).

VI. Synfuel and Other Fossil Fuel Resources

• A. Synfuel

– Synthesized fuel from coal and other naturally occurring sources

– Used in place of oil or natural gas

• B. Include: – Tar sands

– Oil shales

– Gas hydrates

– Liquefied coal

– Coal gas (right)