Chapter 11 Fossil Fuels

1. Chapter 11Fossil Fuels

2. Overview of Chapter 11 • Energy Sources and Consumption • How Fossil Fuels are Formed • Coal • Coal Reserves and Mining • Environmental Impacts • Oil and Natural Gas • Exploration for Reserves of Oil and Natural Gas • Environmental Impacts • Arctic National Wildlife Refuge • Synfuels • US Energy Strategy

3. Energy Sources and Consumption • Energy sources used to be local • Now they are worldwide • Fossil fuels • Nuclear energy • Electricity • Energy consumption is different between developing and developed nations • 20% of world’s population use 60% of the world’s energy sources

4. Per capita energy consumption of selected developed and developing countries

5. Energy consumption in the US • Industries (production) use the most • Heating, cooling, and illuminating building is 1/3

6. Fossil Fuels • 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 • Non-renewable resource • Fossil fuels are created too slowly to replace the reserves we use

7. How Are Fossil Fuels Formed? • 300 million years ago • Climate was mild • Vast swamps covered much of the land • Dead plant material decayed slowly in the swamp environment

8. How Are Fossil Fuels Formed • Over time, layers of sediment accumulated over the dead plant material • Coal • Heat, pressure and time turned the plant material into carbon-rich rock (coal) • Oil • Sediment deposited over microscopic plants • Heat pressure and time turned them into hydrocarbons (oil) • Natural Gas • Formed the same way as oil, but at temperatures higher than 100 °C

9. Coal • Occurs in different grades • Based on variations in heat and pressure during burial • Lignite • Subbitumimous • Bituminous • Anthracite • Most, if not all, coal deposits have been identified • Primarily in northern hemisphere

10. Coal • US has 25% of world’s coal supplies • Known coal deposits could last 200 years • At present rate of consumption

11. 2 Types of Coal Mining • Surface mining (right) • Chosen if coal is within 30m of surface • mineral and energy resources are extracted near Earth’s surface by first removing the soil, subsoil, and overlying rock strata • Subsurface mining • Extraction of mineral and energy resources from deep underground deposits

12. Environmental Impacts of Mining Coal • Surface Mining Control and Reclamation Act (1977) • Requires filling (reclaiming) of surface mines after mining • Expensive! • Reduces Acid Mine Drainage • Requires permits and inspections of active coal mining sights • Prohibits coal mining in sensitive areas • Mountaintop Removal • Fills valleys and streams with debris

13. Environmental Impacts of Burning Coal • Releases large quantities of CO2 into atmosphere • Greenhouse gas • Releases other pollutants into atmosphere • Mercury • Sulfur oxides • Nitrogen oxides • Can cause acid precipitation

14. Making Coal Cleaner • Scrubbers • Fluidized Bed Combustion (below)

15. Oil and Natural Gas • Oil and gas provide 60% of world’s energy • They provide 63% of US’s energy

16. Petroleum Refining • Numerous hydrocarbons present in crude oil (petroleum) are separated • Based on boiling point • Natural gas contains far fewer hydrocarbons than crude oil • Methane, ethane, propane and butane

17. Oil and Natural Gas Exploration • Oil and natural gas migrate upwards until they hit impermeable rock • Usually located in structural traps

18. Oil Reserves • Uneven distribution globally • More than half is located in the Middle East

19. Natural Gas Reserves • Uneven distribution globally • More than half is located in Russia and Iran

20. How long will Supplies Last? • Difficult to determine and estimates vary • Depends on: • How many more deposits will be located • What technology might be available extract deeper resources • Changes in global consumption rates • Experts indicate there may be shortages in 21st century

21. Environmental Impacts of Oil and Natural Gas • Combustion • Increase carbon dioxide and pollutant emissions • Natural gas is far cleaner burning than oil • Production • Disturbance to land and habitat • Transport • Spills- especially in aquatic systems • Ex: Alaskan Oil Spill (1989)

22. 1989 Alaskan Oil Spill

23. 1989 Alaskan Oil Spill • Exxon Valdez hit a reef and spilled 260,000 barrels of crude oil into sound • Largest oil spill in US history • Led to Oil Pollution Act of 1990

24. Case in Point - Arctic National Wildlife Refuge

25. Synfuel and Other Fossil Fuel Resources • Synfuel • A liquid or gaseous fuel that is synthesized from coal and other naturally occurring sources • Used in place of oil or natural gas • Include: • Tar sands • Oil shales • Gas hydrates • Liquefied coal • Coal gas (right)

26. US Energy Strategy • Objective 1: Increase Energy Efficiency and Conservation • Requires many unpopular decisions • Examples • Decrease speed limit to conserve fuel • Eliminate government subsidies • Objective 2: Secure Future Fossil Fuel Energy Supplies • 2 oppositions: environmental and economic

27. US Energy Strategy • Objective 3: Develop Alternative Energy Sources • Who should pay for this? Gas taxes? • Objective 4: Meet the First Three Objectives Without Further Damage to the Environment

28. National Energy Policy (2005)