ENERGY TODAY CHAPTER 8
Energy for the Global Economy • The U.S. is the largest consumer of energy. • Energy use is increasing in most countries.
How We Use Energy • Residential and commercial= houses, office buildings, shopping malls… • Industrial sector= manufacturing plants, paper mills, oil refineries, steel mills, automobile plants, agriculture, mining, construction • Transportation= light duty vehicles, freight trucks, air transport, trains, boats/ships
8.2 Historical Uses of Energy • First, humans used sunlight for energy- ate plants/animals and burned wood for fuel • Mid-1700s – burned coal (also energy from the sun) • 1900’s + - coal, oil and natural gas (advanced technology = greater need for more fuel and more energy content.
8.3 America’s Energy Transitions • When wood burns, it produces about 2760 calories per gram. Coal contains more than 2 times the energy as wood. Therefore, wood replaced coal. • Oil/natural gas use became more common in the 1920s. Oil is easier to use and cleaner than coal. They are also easier and cheaper to transport. By the end of WWII, petroleum was the dominant fossil fuel.
Fossil Fuels – oil, gas, coal Oil: • iseasily stored, transported and consumed • is the leading energy source in the U.S. • Crude oil is the decay of organic matter • Most petroleum is in the form of either liquid crude oil or vapor called natural gas.
Petroleum also exists in solids- tar sands (Alberta, Canada) and shale beds (Colorado, Utah, Wyoming) Most scientists believe oil formed from remains of tiny oceanic plants/animals. These organisms formed layers and layers of material that eventually, under pressure, formed sedimentary rocks such as limestone, and shale. Oil is a hydrocarbon, formed from H and C atoms
After the petroleum formed, it migrated through the rock into permeable and porous rocks. Concentrations of petroleum form reservoirs. • Oil and gas seep up and out until capped by impermeable rock. The lighter gas then migrates to the top.
Most Oil If Found Deep Within The Earth’s Crust In deciding where to drill for oil, scientists look for 1) shale and limestone 2) permeable/porous rock such as sandstone and limestone that may be reservoir rock and 3) a layer of impermeable rock
Oil + Oxygen → CO2 + H2O + heat energy + wastes Wastes may be unburned hydrocarbons, carbon monoxide, nitrogen oxides and sulfur gases.
Uses of Petroleum • The many uses of petroleum • List 5 items from the list that surprised you.
8.5 Natural Gas • Burns cleaner than coal and oil • Burns almost completely and produces almost no harmful byproducts • Natural gas + oxygen → CO2 + H2O + heat
The Industrial Sector Is The Largest User Of Natural Gas • More homes are heated with natural gas than any other type of fuel. • Natural gas is used for raw material processing, food preparation, refinery fuel and power generation • Natural gas provides the base ingredients for products such as plastic, fertilizer, anti-freeze, and fabrics
NATURAL GAS • Is a component of petroleum. • Is mostly methane (CH4) with some ethane, propane and butane. • Natural gas is less dense than petroleum so it is found above petroleum
8.6 Coal • Main source of producing electricity in the U.S. • Large reserves in the U.S. • Coal + O2→ CO2 + heat + waste • Wastes are sulfur dioxide, nitrogen oxides, carbon monoxide, soot, and fly ash
Sulfur is naturally found in coal • Nitrogen oxides form in extreme heat in furnaces and engines • Soot is unburned coal • CO2 is released when coal (C) is burned . Because it is a greenhouse gas, technologies are developed to reduce the amount released.
ORIGIN OF COAL • Coal is fossilized plant matter (can often see bits of wood, bark, leaves and roots) • It is an organic substance made of mostly carbon with small amounts of hydrogen, oxygen, nitrogen and sulfur • Forms in hot, moist places, in stagnant waters- equatorial regions.
Plants die, are buried by water and sediments, and then attacked by anaerobic bacteria. H and O are released by the bacterial action, leaving mostly carbon. • peat → subbituminous coal (lignite) → bituminous coal → anthracite • As heat and pressure affect the peat, water is squeezed out, methane gas escapes and the carbon content becomes more concentrated. • Peat = organic material • subbituminous (lignite) and bituminous coal = sedimentary rock • Anthracite = metamorphic rock
Increasing heat and carbon content Increasing moisture content Lignite (brown coal) Peat (not a 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 Stepped Art Fig. 15-11, p. 383
Anthracite is most desirable for heating because it burns with little smoke. Hard to ignite because most volatiles are gone. Lignite lights easily with lots of smoke. Dangerous because of its high volatility. • Energy content of coal determines its quality and usefulness as a fuel. Anthracite has highest heat content. Bituminous is used mostly for electric power generation.
Coal deposits in the east are of higher quality (bituminous) than those in the West (lignite) which are closer to the surface. • 1/8 of U.S. land lies over coal beds.
MINING METHODS • In past, coal was mined underground, where large rooms were mined with pillars left to support the roof. Work was dangerous, hard and unpleasant. • Now, mining is automated.
60% OF COAL TODAY IS SURFACE MINED • Overlying surface rock (overburden) is removed. • Surface mining(open pit mining) is less dangerous to miners and recovers more coal than underground mining. • Less than 10% of coal, however, is shallow enough to be surface mined • Coal is often located under farm land which must be reclaimed.
NATURAL CAPITAL DEGRADATION Extracting, Processing, and Using Nonrenewable Mineral and Energy Resources Steps Environmental Effects Mining Disturbed land; mining accidents; health hazards; mine waste dumping; oil spills and blowouts; noise; ugliness; heat Exploration, extraction Solid wastes; radioactive material; air, water, and soil pollution; noise; safety and health hazards; ugliness; heat Processing Transportation, purification, manufacturing Use Noise; ugliness; thermal water pollution; pollution of air, water, and soil; solid and radioactive wastes; safety and health hazards; heat Transportation or transmission to individual user, eventual use, and discarding Fig. 14-15, p. 356
TRADE-OFFS Coal Advantages Disadvantages Severe land disturbance, air pollution, and water pollution Ample supplies (225–900 years) High net energy yield Severe threat to human health when burned Environmental costs not included in market price Low cost Large government subsidies Well-developed technology High CO2 emissions when produced and burned Air pollution can be reduced with improved technology Radioactive particle and toxic mercury emissions Fig. 15-15, p. 385
Come up with an acronym (saying) to remember the 4 stages of coal. • Which type of coal is considered a metamorphic rock?
8.7 ELECTRICAL ENERGY • Coal may be the largest and most important source of energy for generating electricity, are also used. • Hydropower, nuclear and natural gas are 3 other energy sources used to produce electricity.
HYDROPOWER • Used almost entirely for generating electricity. • Produces 2.7% of electricity in the U.S. (2005) • Low cost and clean energy • Few sites available to expand use
8.9THERMAL POLLUTION • The goal of power plants is to produce steam. To produce steam, you need large amounts of water that need to be heater to high temperatures. What do you do with all that hot water?
The hot water cannot be released directly into the air or a body of water because: • Blue-green algae may replace more desirable algae. This algae can multiply rapidly and use up oxygen in the water, resulting in fish kills. • Trout may die off because warm water cannot hold as much dissolved oxygen as cold water.
20% OF THE WORLD’S POPULATION DOES NOT HAVE ACCESS TO ELECTRICITY (1.4 billion)