017 Non-Renewable Ch 15

1. Environment & Ecology 017 Non-Renewable Ch 15

2. Central Case: Oil or wilderness on Alaska’s North Slope? To Drill or Not to Drill in the ANWR

3. Alaska’s North Slope

4. Fossil fuels provide most of our energy

5. Renewable energy: supplies will not be depleted by our use Sunlight, geothermal energy, and tidal energy Nonrenewable energy: at our current rates of consumption, we will use up Earth’s accessible store of these sources in a matter of decades to centuries Oil, coal, natural gas, nuclear energy They cannot be replaced in any time span useful to our civilization. Resources are renewable or non-renewable

6. They were formed from organisms that lived 100-500 million years ago. Produced when organic material is broken down in an anaerobicenvironment Bottoms of deep lakes, swamps, and shallow seas Fossil fuels are created from fossils diatoms

7. Petroleum & Natural Gas Formation

8. Fossil fuel reserves are unevenly distributed • Nearly 67% of the world’s proven reserves of crude oil lie in the Middle East. • Russia contains the most natural gas. • The U.S. possesses more coal than any other country.

9. Global fossil fuel reserves

10. It takes energy to make energy • To harness, extract, process, and deliver energy requires substantial inputs of energy. • Roads, wells, vehicles, storage tanks

11. Energy returned on investment (EROI) • Energy returned on investment (EROI): calculated as: energy returned ÷ energy invested • Higher ratios mean we receive more energy than we invest. • Fossil fuels have high EROI, however… • Ratios decline when we extract the easiest deposits first and now must work harder to extract the remaining reserves. • i.e., the EROI for petroleum: 1940s = 100:1, today = 5:1

12. Coal • The world’s most abundant fossil fuel • Coal: organic matter (woody plant material) that was compressed millions of years ago under very high pressure to form dense, solid carbon structures • Very little decomposition occurred

13. Coal contains impurities • Sulfur, mercury, arsenic, and other trace metals • Sulfur content depends on whether coal was formed in salt water or freshwater.

14. Coal is mined using two methods • Strip mining: for deposits near the surface • Subsurface mining: underground deposits • First uses of coal were for direct heating and running steam engines • Today, coal is burned to produce electricity. • Coal combustion turns water to steam, which turns a turbine.

15. Top producers and consumers of coal Fossil fuel use is unevenly distributed

16. Natural gas • The fastest growing fossil fuel in use today • 25% of global commercial energy consumption • Natural gas: consists of methane (CH4) and other volatile hydrocarbons • Biogenic gas: created at shallow depths by bacterial anaerobic decomposition of organic matter • “Swamp gas” • Thermogenic gas: results from compression and heat deep underground • Found above coal or crude oil

17. Top producers and consumers of natural gas

18. Natural gas extraction becomes more challenging • The first gas fields simply required an opening and the gas moved upward. • Most remaining fields require pumping. • Most accessible reserves have been depleted. • Extraction today uses sophisticated techniques such as fracturing, which pumps high-pressure salt water into rocks to crack them.

19. April 2010 Offshore drilling produces much of our gas Deepwater Horizon

20. Heat and pressure underground form petroleum • Oil is the world’s most used fuel. • Its worldwide use over the past decade has risen 17%. • 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.

21. Top producers and consumers of oil

22. Petroleum geologists infer deposit location and size • Estimates for ANWR’s oil deposits = 11.6–31.5 (average = 20.7) billion barrels, enough for 33 months at current consumption rates • But only 4.3–11.8 (average = 7.7) billion barrels are technically recoverable, equivalent to 1 year of consumption

23. Not all oil can be extracted • Some oil would be so hard to extract, it is not worth the cost. • As prices rise, economically recoverable amounts approach technically recoverable amounts. • Proven recoverable reserve: the amount of oil (or any other fossil fuel) that is technically and economically feasible to remove under current conditions • Technology limits what can be extracted. • Economics determines what will be extracted.

24. We drill to extract oil, which has many uses • Exploratory drilling: small, deep holes to determine whether extraction should be done • Oil is under pressure and often rises to the surface. • Once pressure is relieved, pumping is required. • Once extracted, oil is refined. • Separates the hydrocarbons (i.e., gasoline from tar)

25. A petroleum refinery

26. Petroleum products have many uses Oil is refined to create many products, so we should be concerned as we continue depleting it.

27. We may have already depleted half our reserves • Some people calculate that we have used up about 1.1 trillion barrels of oil — ½ of the world’s reserves • Reserves-to-production ratio (R/P ratio): the amount of total remaining reserves divided by the annual rate of production (extraction and processing) • At current levels of production (30 billion barrels/year), we have about 40 years of oil left. • We will face a crisis not when we run out of oil, but when the rate of production begins to decline.

28. We are facing an oil shortage U.S. oil production has already peaked

29. Global oil production is peaking Discoveries of new oil fields peaked 30 years ago, and since then we’ve been extracting and consuming more than discovering.

30. Oil sands can be mined and processed • Oil sands (tar sands): sand deposits with 1–20% bitumen, a thick form of petroleum rich in carbon, poor in hydrogen • Degraded and chemically altered crude oil deposits • Removed by strip mining • Specialized refineries upgrade it into synthetic crude oil • Primarily found in Venezuela and Alberta, Canada

31. Oil shale is abundant in the U.S. west • Oil shale: sedimentary rock filled with kerogen (organic matter) that can be processed to produce liquid petroleum • More than 40% is found in the U.S., mostly on federally owned land in the west • Supplies may equal 600 billion barrels of oil

32. Methane hydrate shows potential • Methane hydrate: molecules of methane in a crystal lattice of water ice molecules • Found in seafloor sediments below 300m • Abundant sources, but undeveloped technology will limit extraction • This resource will likely remain inefficient and expensive.

33. These alternative fossil fuels have downsides • Their net energy values are low because they are expensive to extract and process. • They have low EROI ratios: about 3:1 compared to the 5:1 ratio on crude oil. • Extraction processes devastate the landscape and pollute waterways. • Combustion pollutes the atmosphere just as much as crude oil, coal, and gas. • Will contribute to climate change

34. Fossil fuel emissions pollute the air Carbon emissions from fossil fuel combustion have increased sharply.

35. Fossil fuel use pollutes water • Leaking underground storage tanks can pollute groundwater. • Non-point source oil pollution ultimately ends up in oceans. • Catastrophic tanker oil spills impact marine environments. • Coal mining causes acid mine drainage and habitat destruction. • Drilling requires new roads and infrastructure, which fragment habitats.

36. Scientists anticipate negative impacts in ANWR • Some scientists anticipate damage if ANWR is drilled. • Vegetation killed • Degraded air and water quality • Other scientists say little harm will be done. • ANWR will be developed with environmentally sensitive technology and approaches.

37. Drilling in ANWR will not fill U.S. oil demand ANWR’s estimated 7.7 billion barrels represents just one year’s supply for the U.S at current consumption rates.

38. Nations can become dependent on foreign energy • We are vulnerable to supplies becoming unavailable or expensive. • The U.S. imports 67% of its crude oil, meaning other nations control our energy supplies.

39. The oil embargo of the 1970s caused panic • OPEC’s (Organization of Petroleum Exporting Countries) oil embargo caused widespread panic, skyrocketing prices, and spurred inflation.

40. Oil supply and prices affect nation’s economies • Because the politically volatile Middle East has the majority of oil reserves, crises are a constant concern for the U.S. • Despite political disagreements, the U.S. has a close relationship with Saudi Arabia because Saudi Arabia owns 22% of the world’s oil reserves.

41. Residents may or may not benefit from reserves • Extraction can benefit residents of the area with: • Increased job opportunities • Residents in Alaska are paid dividends by the government • But residents are not always compensated for pollution and displacement. • Profits go to oil companies and governments. Nigeria

42. How much longer can we depend on fossil fuels? • Because they are fossil fuels they DO have a life expectancy • “Oil has 40 – 50 years left” • In 1960 they said this too! – what has happened is that we have found new reserves of oil and new technology has made the oil we use last longer

43. Nuclear Power • US Power Reactors • 104 commercial reactors generating 20% of electric power • The US is the world’s largest supplier of nuclear power • No new power reactor has been built in the US since 1978

44. Nuclear Power • Conflict. • Less air pollution • Less env. damage for extracting • But there are issues of nuclear weaponry, radioactive waste disposal, and previous accidents. • The U.S. generates the most electricity from nuclear power. • 20% of U.S. electricity • Other nations rely more heavily on nuclear power (i.e., France gets 78% of its electricity from nuclear power).

45. Fission releases nuclear energy • Nuclear energy:the energy that holds together protons and neutrons within the nucleus of an atom

46. Coal versus nuclear power

47. Spent fuel rods must be stored • Nuclear waste will remain radioactive for thousands of years. • Is currently held in temporary storage at nuclear power plants across the U.S. and the world • Spent fuel rods are sunk in pools of cooling water to minimize radiation leakage. • U.S. power plants store 56,000 metric tons of high-level radioactive waste, as well as much more low-level radioactive waste. • Waste is held at 125 sites in over 39 states. • Over 161 million U.S. citizens live within 125 km (75 mi) of temporarily stored waste.

48. Waste Storage Alternatives • Leave It Where It Is • Deep Geologic Disposal • Yucca Mountain, Nevada • Salt Cave Disposal • WIPP near Carlsbad, New Mexico • Very Deep Holes (6 miles) • Ice-Sheet Disposal • Space Disposal • Sub-Seabed Disposal • Island Geologic Disposal • Deep-Well Injection Disposal • Vitrification (Glass Waste) • Reprocessing

49. U.S. storage of high-level radioactive waste

50. Waste storage at Yucca Mountain, Nevada Nuclear waste managers want to send all waste to a central repository that can be heavily guarded With final approval, Yucca Mountain will begin receiving wastes by 2017.