Conventional Energy

1. Conventional Energy Chapter 21 Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

2. Outline: • Energy History • How Energy Is Used • Coal • Oil • Natural Gas • Nuclear Power • Fission • Reactors • Waste Management • Fusion Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

3. WHAT IS ENERGY • Work - Application of force through a distance. • Energy - The capacity to do work. • Power - Rate at which work is done. • Calorie - Amount of energy necessary to heat 1 gram of water 1oC. • Joule - Amount of work done when a force of 1 newton is exerted over 1 meter. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

4. Energy History • Muscle power provided by domestic animals has been important since dawn of agriculture 10,000 years ago. • World Oil Use peaked in 1979. • Oil prices rose ten-fold in 1970’s. • Early 1980’s saw increased interest in conservation and renewable energy. • Oil glut in mid 1980’s caused prices to fall. • US now imports over half annual oil supply. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

5. Current Energy Sources • Fossil Fuels currently provide about 85% of all commercial energy in the world. • Biomass fuels contribute about 6% of commercial energy. • Other renewable sources make up 4-5% of commercial power. • Nuclear power makes up 4-5% of commercial power. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

6. Worldwide Commercial Energy Production Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

7. Per Capita Consumption • Richest 20 countries consume nearly 80% of natural gas, 65% of oil, and 50% of coal production annually. • On average, each person in the US and Canada uses more than 300 GJ of energy annually. • In poorest countries of the world, each person generally consumes less than one GJ annually. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

8. Per Capita Energy Use and GNP Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

9. HOW ENERGY IS USED • Largest share of energy used in the US is consumed by industry (36.5%). • Residential and Commercial buildings use 34% of primary energy consumed in US. • Transportation consumes about 26% of all energy used in the US. • Three trillion passenger miles and 600 billion ton miles of freight carried annually by motor vehicles in the US. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

10. How Energy Is Used • About half of all energy in primary fuels is lost during conversion to more useful forms while being shipped, or during use. • Nearly two-thirds of energy in coal being burned to generate electricity is lost during thermal conversion in the power plant. • Another 10% is lost during transmission and stepping down to household voltages. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

11. COAL • Fossilized plant material preserved by burial in sediments and compacted and condensed by geological forces into carbon-rich fuel. • Most laid down during Carboniferous period (286 million to 360 million years ago). Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

12. Coal • Resources and Reserves • World coal deposits are ten times greater than conventional oil and gas resources combined. • Under current consumption rates, this could last several thousand years. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

13. Proven-In-Place Coal Reserves Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

14. Coal • Mining • Between 1870 and 1950, more than 30,000 coal miners died of accidents and injuries in Pennsylvania alone. • Several thousands have died of respiratory diseases. • Black Lung Disease - Inflammation and fibrosis caused by accumulation of coal dust in the lungs or airways. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

15. Coal • Air Pollution • Coal burning releases radioactivity and toxic metals into the atmosphere. • Coal combustion is responsible for 25% of all atmospheric mercury pollution in the US. • Coal contains up to 10% sulfur by weight. • Unless removed by washing or flue-gas scrubbing, sulfur is released and oxidizes to sulfur dioxide or sulfate. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

16. OIL • Petroleum is formed very similar to oil - Organic material buried in sediment and subjected to high pressure and temperature. • Oil Pool usually composed of individual droplets or thin film permeating spaces in porous sandstone or limestone. • At least half of total deposit is usually uneconomical to pump out. • Secondary oil recovery techniques. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

17. Oil Recovery Process Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

18. OIL • Resources and Reserves • Total amount of oil in the world is estimated at 4 trillion barrels. (Half is thought to be ultimately recoverable) • In 1999, proven reserves were estimated at 1 trillion barrels. • As oil becomes depleted and prices rise, it will likely become more economical to find and bring other deposits to market. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

19. Proven Recoverable Oil Reserves Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

20. Oil • Imports and Domestic Supplies • The US has used about 40% of its original recoverable petroleum resource. • Of the 120 billion barrels thought to remain, 58 billion are proven-in-place. • Until 1947, the US was the world’s leading oil export country. • By 1998, the US was importing 10 million barrels per day - Half of total consumption. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

21. Oil • Oil Shales and Tar Sands • Estimates of total oil supply usually do not reflect large potential from unconventional oil sources such as shale oil and tar sand. • Could potentially double total reserve. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

22. NATURAL GAS • World’s third largest commercial fuel. • 23% of global energy consumption. • Produces half as much CO2 as equivalent amount of coal. • Most rapidly growing energy source. • Difficult to ship long distances, and to store in large quantities. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

23. Natural Gas • Resources and Reserves • Proven world reserves of natural gas are 3,200 trillion cubic feet. • Current reserves represent roughly 60 year supply at present usage rates. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

24. Proven-In-Place Natural Gas Reserves Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

25. Unconventional Gas Sources • Methane hydrate - Small individual molecules of natural gas trapped in a crystalline matrix of frozen water. • Thought to hold 10,000 gigatons of carbon, or twice as much as combined amount of all traditional fossil fuels combined. • Difficult to extract, store, and ship. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

26. NUCLEAR POWER • President Dwight Eisenhower, 1953, “Atoms for Peace”speech. • Nuclear-powered electrical generators would provide power “too cheap to meter.” • Between 1970 and 1974, American utilities ordered 140 new reactors for power plants. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

27. Nuclear Power • After 1975, only 13 orders were placed for new nuclear reactors, and all of those were subsequently cancelled. • In all, 100 of 140 reactors on order in 1975 were cancelled. • Electricity from nuclear power plants was about half the price of coal in 1970, but twice as much in 1990. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

28. Nuclear Power Plant History Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

29. How Do Nuclear Reactors Work • Most commonly used fuel is U235, a naturally occurring radioactive isotope of uranium. • Occurs naturally at 0.7% of uranium, but must be enriched to about of 3%. • Formed in cylindrical pellets (1.5 cm long) and stacked in hollow metal rods (4 m long). • About 100 rods and bundled together to make a fuel assembly. • Thousands of fuel assemblies bundled in reactor core. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

30. How Do Nuclear Reactors Work • When struck by neutrons, radioactive uranium atoms undergo nuclear fission, releasing energy and more neutrons. • Triggers nuclear chain reaction. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

31. Nuclear Fission Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

32. How Do Nuclear Reactors Work • Reaction is moderated in a power plant by neutron-absorbing solution (Moderator). • In addition, Control Rods composed of neutron-absorbing material are inserted into spaces between fuel assemblies to control reaction rate. • Water or other coolant is circulated between the fuel rods to remove excess heat. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

33. Kinds of Reactors • Seventy percent of nuclear power plants are pressurized water reactors. • Water circulated through core to absorb heat from fuel rods. • Pumped to steam generator where it heats a secondary loop. • Steam from secondary loop drives high-speed turbine producing electricity. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

34. Kinds of Reactors • Both reactor vessel and steam generator are housed in a special containment building preventing radiation from escaping, and providing extra security in case of accidents. • Under normal operating conditions, a PWR releases very little radioactivity. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

35. PWR Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

36. Kinds of Reactors • Simpler, but more dangerous design is a boiling water reactor. • Water from core boils to make steam, directly driving turbine generators. • Highly radioactive water and steam leave containment structure. • Canadian deuterium reactors - Operate with natural, un-concentrated uranium. • Graphite moderator reactors - Operate with a solid moderator instead of a liquid. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

37. Alternative Reactor Designs • High-Temperature, Gas-Cooled Reactors • Uranium encased in tiny ceramic-coated pellets. • Process-Inherent Ultimate Safety Reactors • Reactor core submerged in large pool of boron-containing water within a massive pressure vessel. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

38. Breeder Reactors • Breeder reactors create fissionable plutonium and thorium isotopes from stable forms of uranium. • Uses plutonium reclaimed from spent fuel from conventional fission reactors as starting material. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

39. Breeder Reactors Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

40. Breeder Reactor Drawbacks • Reactor core must be at very high density, thus liquid sodium used as a coolant. • Corrosive and difficult to handle. • Core will self-destruct within a few seconds if primary coolant is lost. • Produces weapons-grade plutonium. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

41. RADIOACTIVE WASTE MANAGEMENT • Until 1970, the US, Britain, France, and Japan disposed of radioactive waste in the ocean. • Production of 1,000 tons of uranium fuel typically generates 100,000 tons of tailings and 3.5 million liters of liquid waste. • Now approximately 200 million tons of radioactive waste in piles around mines and processing plants in the US. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

42. Radioactive Waste Management • About 100,000 tons of low-level waste (clothing) and about 15,000 tons of high-level (spent-fuel) waste in the US. • For past 20 years, spent fuel assemblies have been stored in deep water-filled pools at the power plants. (Designed to be temporary.) • Many internal pools are now filled and a number plants are storing nuclear waste in metal dry casks outside. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

43. Radioactive Waste Management • US Department of Energy announced plans to build a high-level waste repository near Yucca Mountain Nevada in 1987. • Facility may cost between $10 and 35 billion, and will not open until at least 2010. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

44. Decommissioning Old Nuclear Plants • Most plants are designed for a 30 year operating life. • Only a few plants have thus far been decommissioned. • General estimates are costs will be 2-10 times more than original construction costs. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

45. CHANGING FORTUNES • Public opinion has fluctuated over the years. • When Chernobyl exploded in 1985, less than one-third of Americans favored nuclear power. • Now, half of all Americans support nuclear-energy. • Currently, 103 nuclear reactors produce about 20% of all electricity consumed in the US. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

46. Changing Fortunes • With natural gas prices soaring, and electrical shortages looming, many sectors are once again promoting nuclear reactors. • Over the past 50 years, the US government has provided $150 billion in nuclear subsidies, but less than $5 billion to renewable energy research. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

47. NUCLEAR FUSION • Nuclear Fusion - Energy released when two smaller atomic nuclei fuse into one large nucleus. (Sun) • Temperatures must be raised to 100,000,000o C and pressure must reach several billion atmospheres. • Magnetic Confinement • Inertial Confinement • Despite 50 years and $25 billion, fusion reactors have never produced more energy than they consume. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

48. Summary: • Energy History • How Energy Is Used • Coal • Oil • Natural Gas • Nuclear Power • Fission • Reactors • Waste Management • Fusion Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.

49. Cunningham - Cunningham - Saigo: Environmental Science 7th Ed.