Conventional Energy

1. Conventional Energy

2. Outline • Energy History • How Energy Is Used • Coal • Oil • Natural Gas • Nuclear Power • Fission • Reactors • Waste Management • Fusion

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 1o C. • Joule - Amount of work done when a force of 1 newton is exerted over 1 meter.

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. • U.S. now imports over half annual oil supply.

5. Current Energy Sources • Fossil fuels currently provide about 86% of all commercial energy in the world. • Hydroelectric dams supply about 7% of commercial power. • Nuclear power makes up about 6.5 % of commercial power, but about 20% of electric power in more-developed countries.

6. Worldwide Commercial Energy Production

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 U.S. and Canada uses more than 300 GJ (equivalent to 60 barrels of oil) of energy annually. • In poorest countries of the world, each person generally consumes less than one GJ annually.

8. Per Capita Energy Use and GDP

9. HOW ENERGY IS USED • Largest share of energy used in the U.S. is consumed by industry (33%). • Residential and Commercial buildings use 20% of primary energy consumed in U.S.. • Transportation consumes about 27% of all energy used in the U.S.. • Three trillion passenger miles and 600 billion ton miles of freight carried annually by motor vehicles in the U.S..

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.

11. U.S. Energy Flow

12. 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).

13. 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.

14. Proven-In-Place Coal Reserves

15. 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.

16. 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 U.S.. • 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.

17. 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.

18. Oil Recovery Process

19. 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 2003, 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.

20. Proven Oil Reserves

21. Oil • Imports and Domestic Supplies • The U.S. 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 U.S. was the world’s leading oil export country. • By 1998, the U.S. was importing 10 million barrels per day - Half of total consumption.

22. 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.

23. 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.

24. Natural Gas • Resources and Reserves • Proven world reserves of natural gas are 5,500 trillion ft3. • Current reserves represent roughly 60 year supply at present usage rates. • Proven reserves in North America are about 250 trillion ft3.

25. Proven Natural Gas Reserves

26. 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.

27. 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.

28. 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.

29. Nuclear Power Plant History

30. 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 are bundled together to make a fuel assembly. • Thousands of fuel assemblies bundled in reactor core.

31. How Do Nuclear Reactors Work • When struck by neutrons, radioactive uranium atoms undergo nuclear fission, releasing energy and more neutrons. • Triggers nuclear chain reaction.

32. Nuclear Fission

33. 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.

34. 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.

35. 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.

36. PWR

37. 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.

38. 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.

39. 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.

41. 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.

42. RADIOACTIVE WASTE MANAGEMENT • Until 1970, the U.S., 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 U.S..

43. 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 U.S.. • 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.

44. Radioactive Waste Management • U.S. 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.

45. 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.

46. CHANGING FORTUNES OF NUCLEAR POWER • 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 U.S..

47. 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 U.S. government has provided $150 billion in nuclear subsidies, but less than $5 billion to renewable energy research.

48. 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.

50. Summary • Energy History • How Energy Is Used • Coal • Oil • Natural Gas • Nuclear Power • Fission • Reactors • Waste Management • Fusion