Chapter 11 Fossil Fuels

Overview 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 Arctic National Wildlife Refuge Synfuels US Energy Strategy

Energy Sources and Consumption Energy sources used to be local Now they are worldwide Fossil fuels (55.5% imported) 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 (developed uses 8x’s more than developing)

Per capita energy consumption of selected developed and developing countries

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

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 We will have to transition to other sustainable fuels in the future

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 Plants include giant ferns, horsetails, and club mosses

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

Coal Occurs in different grades Lignite Subbitumimous Bituminous 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

Coal Types and Quality Lignite –poor quality, dark brown, 30% carbon, $11.41 (per 2000 lbs to mine), heat value 6000 btu/lb Subbituminous – Poor quality but better, dull black, 40% carbon, $7.12, heat value 9000 btu/lb Bituminous – also called soft coal, high sulfur , 50-70% carbon, $24.15 to mine, 13000 btu/lb Antracite- black, high quality, low sulfur,90% carbon, $40.90 to mine, 14,000 btu/lb (fig 10.1)

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

2 Types of Coal Mining Surface mining (right) Subsurface mining 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 Surface mine near Wyoming

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 Most land destructive tecnique

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 Dead trees enveloped in acid fog on Mt. Mitchell, North Carolina

Making Coal Cleaner Scrubbers Fluidized Bed Combustion (below) Coal and limestone suspended Coal burns and limestone neutralizes most of sulfur dioxide Heat converts water to steam This powers industrial processes

Oil and Natural Gas Oil and gas provide 60% of world’s energy They provide 63% of US’s energy, 23% provided by coal

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

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

Oil Reserves Uneven distribution globally More than half is located in the Middle East which includes Iran, Iraq, Kuwait, Oman, Qatar, Saudi Arabia, Syria, Yemen, and the United Arab Emirates

Natural Gas Reserves Uneven distribution globally More than half is located in Russia and Iran (app. 48% of worlds deposits)

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 to extract deeper resources Changes in global consumption rates Experts indicate there may be shortages in 21st century Long lines at gas station as a result of the OPEC oil embargo in 1973

Environmental Impacts of Oil and Natural Gas Combustion Increase carbon dioxide and pollutant emissions (nitrogen oxides/photochemical smog) 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)

1989 Alaskan Oil Spill Water currents caused the oil to spread hundreds of miles

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 Worker attempting to cleanup rocky shoreline of Eleanor Island

Case in Point - Arctic National Wildlife Refuge

Synfuel and Other Fossil Fuel Resources 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)

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

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

National Energy Policy (2005)