Welcome to APES!! Have a seat and talk about this with the people around you: Should the government raise taxes on gasoline to reflect its true cost? a. Yes; that would make people conserve gasoline. b. Yes, but poor people would need subsidies to help them buy gasoline. c. No; I don‛t want to pay more for gasoline. d. I don‛t care; I have enough money to pay for expensive gasoline. This lecture will help you understand: • Our energy sources • Coal • Natural gas • Crude oil • Alternative fossil fuels • Environmental impacts of fossil fuels • Political, social, and economic aspects • Conserving energy and enhancing efficiency Central Case: Oil or wilderness on Alaska’s North Slope? • Alaska’s remote North Slope ­A pristine wilderness to some ­Untapped oil riches to others • The Arctic National Wildlife Refuge is the focus of intense debate ­Should the “1002 Area”be opened to drilling? • Opponents fear that drilling will sacrifice our national heritage for little gain The three regions of Alaska’s North Slope • The National Petroleum Reserve–Alaska (NPR–A) ­Supposed to remain untapped unless the nation faces an emergency ­Open ecologically sensitive areas for drilling in 2006 • Prudhoe Bay consists of state lands that are drilled for oil ­Which is transported via the trans­Alaska pipeline to the port of Valdez • The Arctic National Wildlife Refuge (ANWR) ­Federal land set aside for wildlife and to preserve pristine ecosystems ­It has been called the “Serengeti of North America” Alaska’s North Slope We use a variety of energy sources • We use energy in our homes, machinery, and vehicles and to provide comfort and conveniences • Most of our energy comes from the sun ­Solar, wind, hydroelectric, photosynthesis, biomass • Fossil fuels = highly combustible substances from the remains of organisms from past geologic ages • A great deal of energy emanates from Earth’s core ­Geothermal power • Immense amounts of energy reside in an atom’s bonds ­This energy provides us with nuclear power Fossil fuels: our dominant source of energy • Global consumption is at its highest level ever • The high­energy content of fossil fuels makes them efficient to burn, ship, and store • Electricity = a secondary form of energy that is easy to transfer and apply to a variety of uses Oil, coal, and natural gas have replaced biomass as our dominant sources of energy Resources are renewable or nonrenewable • Renewable energy = supplies will not be depleted by our use ­Sunlight, geothermal energy, and tidal energy • Nonrenewable energy = we will use up Earth’s accessible store in decades to centuries ­Oil, coal, natural gas, nuclear energy ­To replenish the fossil fuels we have depleted so far would take millions of years Fossil fuels are created from fossils • Fossil fuels were formed from organisms that lived 100–500 million years ago • Aerobic decomposition = organic material is broken down and recycled in the presence of air • Anaerobic decomposition = occurs with little or no air ­Deep lakes, swamps ­Produces fossil fuels Fossil fuel reserves are unevenly distributed • Some regions have substantial reserves ­Whereas others have very few • How long a nation’s reserves will last depends on how much the nation extracts, uses, exports, and imports • Nearly 67% of the world’s proven reserves of crude oil lie in the Middle East ­Russia holds the most natural gas ­The U.S. possesses more coal than any other country Developed nations consume lots of energy • People in developed regions consume far more energy than those in developing nations ­Using 100 times more energy per person • Energy use in industrialized nations is evenly divided between transportation, industry, and other uses • Developing nations use energy for subsistence activities ­Agriculture, food preparation, and home heating ­They use manual or animal energy, not fossil fuels Regions vary greatly in energy consumption The U.S. has 4.5% of the population but uses 20% of the world’s energy It takes energy to make energy • We don’t get energy for free • To harness, extract, process, and deliver energy requires substantial inputs of energy ­Drilling for oil requires roads, wells, vehicles, storage tanks, pipes, housing, etc. ­All this requires energy • Net energy = the difference between energy returned and energy invested ­Net energy = energy returned – energy invested Energy returned on investment (EROI) • Energy returned on investment (EROI) = energy returned/energy invested ­Higher ratios mean we receive more energy than we invest ­Fossil fuels have high EROI • EROI ratios can change ­They decline when we extract the easiest deposits first ­We now must work harder to extract the remaining reserves ­U.S. oil EROI ratios have gone from 100:1 to 5:1 Coal • The world’s most abundant fossil fuel ­Created 300–400 million years ago • Coal = organic matter (woody plant material) ­Compressed under very high pressure in swamps to form dense, solid carbon structures ­Very little decomposition occurred Coal is mined using two major methods • Strip mining = for deposits near the surface ­Heavy machinery removes huge amounts of earth to expose the coal • Subsurface mining = underground deposits are reached by digging tunnels to follow seams (layers) of coal • Mountaintop removal = entire mountaintops are cut off ­Environmentally destructive ­Common in the Appalachian Mountains Coal use has a long history • Cultures have used coal for centuries ­Ancient China, Roman Empire, the Hopi nation • Coal helped drive the Industrial Revolution ­It fueled furnaces to produce steam • Coal is used to generate electricity ­Converting water to steam, which turns a turbine • The U.S. and China are the primary producers and consumers of coal ­It provides half the U.S. electrical generating capacity A typical coal­fired power plant Coal varies in its qualities • Coal varies in water and carbon content and its amount of potential energy • Peat = organic material that is broken down anaerobically ­It is wet, near the surface, and not well compressed • Additional pressure, heat, and time turn peat into coal ­Lignite = least compressed ­Sub­bituminous and bituminous ­Anthracite = most compressed and has the most energy Coal contains impurities • It has sulfur, mercury, arsenic, and other trace metals • The sulfur content depends on whether coal was formed in salt water or freshwater ­Coal in the eastern U.S. is high in sulfur because it was formed in marine sediments • Impurities are emitted when coal is burned ­Unless pollution control measures are used ­Ways to reduce pollution must be found • The Earth holds enough coal to last a few hundred years Natural gas burns more cleanly than coal • The fastest growing fossil fuel in use today ­25% of global commercial energy consumption • It is versatile and clean­burning ­Emits ½ as much CO2 as coal, ⅔ as much as oil • It is used to generate electricity, heat homes, and cook • Liquefied natural gas (LNG) = gas converted to liquid ­Can be shipped but there are risks of explosions • Russia leads the world in production ­The U.S. leads the world in use • World supplies are projected to last about 60 more years Natural gas is formed in two ways • Natural gas = methane (CH4) and other volatile hydrocarbons • Biogenic gas = pure methane created at shallow depths by bacterial anaerobic decomposition of organic matter ­“Swamp gas” • Thermogenic gas = methane and other gases arise from compression and heat deep underground • Most of the gas that is extracted commercially • Kerogen = organic matter that results when carbon bonds begin breaking ­Source material for natural gas and crude oil Natural gas is often wasted • Coalbed methane = from coal seams ­Leaks to the atmosphere during mining ­Contributes to climate change • In remote oil­drilling areas, natural gas is flared (burned off) ­In Alaska, gas captured during oil drilling is being reinjected into the ground for future use • Landfills produce biogenic natural gas ­Operators are capturing and selling it Natural gas extraction becomes challenging • The first gas fields simply required an opening ­The gas moved upward • Most remaining fields require pumping by horsehead pumps • Most accessible reserves have been depleted ­Fracturing pumps high­pressure salt water into rocks to crack them Offshore drilling on the seafloor • Requires technology to withstand wind, waves, and currents ­Produces 1/3 of our oil and 13% of our natural gas • In 2008, Congress lifted a drilling moratorium along U.S. coasts ­In 2010, President Obama said vast areas would be opened for drilling • British Petroleum’s Deepwater Horizon exploded ­Producing the worst oil spill in U.S. history Heat and pressure form petroleum • Oil is the world’s most used fuel ­Accounts for 35% of world’s energy use ­The U.S. uses the most, but China’s and India’s use is increasing • Crude oil (petroleum) = a mixture of hundreds of different types of hydrocarbon molecules ­Formed 1.5–3 km (1–2 mi) underground ­Dead organic material was buried in marine sediments and transformed by time, heat, and pressure Petroleum geologists find deposits • Petroleum occurs in isolated deposits ­Collecting in porous layers under impermeable layers • Geologists drill cores and survey the ground and air to predict where fossil fuels may lie • Of the 11.6–31.5 billion barrels of oil in the Arctic National Wildlife Refuge, only 4.3–11.8 billion barrels are “technologically recoverable” with current technology Not all oil can be extracted • Some oil is so hard to extract, it is not worth the cost ­As