Chapter 12 Nonrenewable Energy Resources

1. Chapter 12 Nonrenewable Energy Resources

2. We use a variety of energy sources • Energy is the capacity to do work. • Work is when a force acts for a certain distance. • All natural ecosystems must have energy and our modern human civilization must have energy also. In fact, without energy, human civilization ceases to exist.

4. Which sector uses the most energy in the U.S.?

6. Two Rules We Cannot Break: the First and Second Laws of Thermodynamics • First Law of Thermodynamics - energy can never be created or lost; it can only be changed from one type to another.

7. Electrical • Chemical • Mechanical • Heat/thermal • Light • Sound • Kinetic • Potential • Energy transforms to different forms!

8. Second Law of Thermodynamics - high quality energy always degrades to low quality energy (low temperature heat) and can never be recovered.

9. Mechanicalenergy(moving,thinking,living) • Chemical • energy • (photosynthesis) • Chemical • energy • (food) • Solar • energy • Waste • Heat • Waste • Heat • Waste • Heat • Waste • Heat • Fig. 2-14, p. 45

10. What is a BTU? • A British Thermal Unit is the amount of energy need to raise one pound of water one degree Fahrenheit • One BTU = 252 calories • One BTU = 1,055 joules

12. What is a joule (J)? • It is the force of one newton over one meter • Work needed to make 1 watt of power for 1 second • One joule = 0.238 calories • One joule = 0.0009 BTU’s

13. What is a calorie? • A calorie is the amount of energy it takes to heat one gram of H2O one degree Celsius • A food Calorie (with a big “C”) is 1000 calories or a single kcal • One calorie = 4.2 joules • One calorie = 0.004 BTU’s

14. What is a kilowatt-hour? • A kilowatt-hour is using a thousand watts of electricity for one hour. • If you turned on ten 100-watt light bulbs for an hour, you have used up one kilowatt-hour.

15. 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

16. Fossil fuels: our dominant source of energy Oil, coal, and natural gas have replaced biomass as our dominant sources of energy • Global consumption is at its highest level ever • The high-energy 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

17. The energy stream of the U.S. is complex The U.S. energy stream is dominated by coal, oil, and natural gas

18. Nonrenewable Energy • Nonrenewable energy resources- we will use up Earth’s accessible store in decades to centuries • fossil fuels (coal, oil, natural gas) and nuclear fuels.

19. Energy Use • Commercial energy sources- those that are bought and sold, such as coal, oil and natural gas. • Subsistence energy sources- those gathered by individuals for their own use such as wood, charcoal and animal waste.

20. 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

21. Energy Return on Energy Invested • Calculation of how much energy we get out of an energy source for every unit of energy expended on its production. • EROI= energy obtained from the fuel energy invested to obtain • Higher ratios mean we receive more energy than we invest • Fossil fuels have high EROI

22. Process of Energy Use

23. Overall Fuel Efficiency of U.S. Automobiles

24. Electricity Generation • The burning fuel from coal transfers energy to water, which becomes steam. • The kinetic energy contained within the steam is transferred to the blades of a turbine, a large device that resembles a fan. • As the energy in the steam turns the turbine, the shaft in the center of the turbine turns the generator. • This mechanical motion generates energy.

25. A typical coal-fired plant

26. Energy Efficiency • Most coal burning power plants are about 35% efficient. • Combined cycle-a power plant that uses both exhaust gases and steam turbines to generate electricity.

27. Cogeneration • Cogeneration- using a fuel to generate electricity and to produce heat. • If steam is used for industrial purposes or to heat buildings it is diverted to turn a turbine first. • This improves the efficiency to as high as 90%.

28. Energy Fuels used for electricity generation in the U.S. in 2012

29. 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

30. Coal • Coal- a solid fuel formed primarily from the remains of trees, ferns, and other plant materials that were preserved 280-360 million years ago. • Four types of coal ranked from lesser to greater age, exposure to pressure, and energy content. • These four types are: lignite, sub-bituminous, bituminous, and anthracite. • The largest coal reserves are in the United States, Russia, China, and India.

31. Coal

32. 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 • Sub-bituminous and bituminous • Anthracite = most compressed and has the most energy

33. 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

34. Clean coal technologies • Clean coal technologies = technologies, equipment, and approaches to remove chemical contaminants while generating electricity from coal • Scrubbers chemically convert or remove pollutants • Removing sulfur dioxide or nitrogen oxides • Coal that contains lots of water can be dried • Gasification = coal is converted into cleaner synthesis gas (syngas) • Which can be used to turn a gas or steam turbine • These technologies have reduced pollution • But clean coal is still a dirty way to generate power

35. Can we capture and store carbon? • Even very clean coal still releases greenhouse gases • Carbon capture and carbon storage (sequestration) • CCS captures CO2 emissions • Then converts it to a liquid and stores it underground or in the ocean • The $1.5 billion FutureGen project will design, construct, and operate a coal-burning power plant for electricity while capturing and storing carbon underground • This technology is still too unproven to depend on • It prolongs our dependence on fossil fuels

36. 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

37. Advantages and Disadvantages of Coal

38. 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

39. Petroleum

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

41. We drill to extract oil • Exploratory drilling = small, deep holes to determine whether extraction should be done • Oil is under pressure and often rises to the surface • Drilling reduces pressure, and oil becomes harder to extract • Primary extraction = the initial drilling and pumping of available oil • Secondary extraction = solvents, water, or steam is used to remove additional oil, but it is expensive • We lack the technology to remove every bit of oil • As prices rise, it becomes economical to reopen a well

42. Petroleum products have many uses Petroleum products are central to our lives

43. We may have depleted half our reserves • We have used up 1.1 trillion barrels of oil • Half our 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

44. Advantages and Disadvantages of Petroleum

45. Natural Gas • Natural gas- exists as a component of petroleum in the ground as well as in gaseous deposits separate from petroleum. • Contains 80 to 95 percent methane and 5 to 20 percent ethane, propane, and butane.

46. 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 clean-burning • 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

47. Natural gas is often wasted • Coalbed methane = from coal seams • Leaks to the atmosphere during mining • Contributes to climate change • In remote oil-drilling 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

48. 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 high-pressure salt water into rocks to crack them

49. Advantages and Disadvantages Natural Gas

50. Other Fossil Fuels/Synfuels • Oil sands- slow-flowing, viscous deposits of bitumen mixed with sand, water, and clay. • Bitumen (tar or pitch)- a degraded type of petroleum that forms when a petroleum migrates close to the surface, where bacteria metabolize some of the light hydrocarbons and others evaporate.