Energy: Fossil Fuels

Transcription

1 Energy: Fossil Fuels

2 Power Units Power is the at which work is done/energy is consumed. Energy= ability to do work. The joule is a unit of both work and energy. Power = energy/time or work/time Power Units: o Watt = I Joule/second o Kilowatt (kw) = 10 3 W o Megawatt(MW) = 10 6 W o Gigawatt (GW) = 10 9 W o Terawatt (TW) = W

3 Discuss with your table partner: A correct unit for energy is the because. It is not since this would indicate. Rewrite the power formula to solve for energy. Determine which of the following is a correct unit for energy and explain why. A.Watt/hour B.Watt-hour C. Watt D. Hour/Watt

4 Discuss with your table partner: If a 75 Watt light bulb is turned on for 4,000 hours per year, how much energy is consumed by this bulb each year? If energy costs $.11/kwh, how much does it cost to light this bulb each year? (kwh = kilowatt- hour)

5 Discuss with your table partner: Review the 1 st and 2 nd Laws of Thermodynamics and the definition of entropy.

6 First Law of Thermodynamics: o Energy is ; o Einstein showed energy & matter can be interconverted; E = mc 2

7 Second Law of Thermodynamics: when energy is converted from one form to another, o Entropy. Entropy is a measure of ; increased entropy means increased. o Degraded energy generally in the form of.

8 Discuss with your table partner: Compare the energy usage in more developed nations to less developed. Review the different types of energy. More Developed Nations Less Developed Nations

9 Energy Use in the U.S. The United States is the largest user (& waster) of commercial energy. U.S. has 4.6% of world population, but uses 24% of the energy; 84% of the U.S. energy comes from nonrenewable fossil fuels of the U.S. energy comes from nuclear power; only 7% of the U.S. energy is renewable sources (hydropower, geothermal, solar, biomass).

10 What is Net Energy? Net energy: The total useful energy available from a resource. Example: if 8 units of energy are wasted for every 10 units extracted, then there is a net energy of 2 units; Net energy ratio: The ratio of useful energy produced to the energy used to produce it; the higher the ratio the greater the net energy yield; Example: for the above problem the net energy ratio is 10/8 = 1.25.

11 Net Energy Ratios Net energy ratios for various energy systems used for transportation.

12 Oil Petroleum or crude oil is a fossil fuel, produced by the decomposition of deeply buried organic matter. Crude oil is a complex mixture of hydrocarbons, with small amounts of sulfur, oxygen, & nitrogen impurities; primary oil recovery involves drilling a well & pumping oil that flows by gravity into the bottom of the well; secondary oil recovery involves injecting water in nearby wells to force remaining heavy oil to the surface; tertiary or enhanced oil recovery involves using

13 iscuss with your table partner: Which form of oil recovery has the highest net energy? Which has the lowest? Explain your answers. Oil Recovery has the lowest net energy because recovery has the highest net energy.

14 Crude oil and natural gas are often found together in sedimentary rock, with the oil dispersed in pores of the rock formation. Oil drilling platform Gas well Oil well Pipeline Pump Oil storage Mined coal Coal seam

15 Crude Oil Refining The processing of crude oil is called refining. It involves separating components based on their Low Boiling point High Boiling point gasoline & aviation fuel are among the most volatile components; heating oil is less volatile, but still burns readily; diesel oil is still less volatile, and is a common fuel for trucks, buses, & heavy machinery; grease, wax, & asphalt are the least volatile, most dense materials separated; petrochemicals derived from oil are used for synthesizing industrial organic chemicals, pesticides, plastics, synthetic fibers, paints, medicines, & many other products.

16 Lowest Boiling Point Gases Gasoline Aviation fuel Heating oil Diesel oil Naphtha Heated crude oil Furnace Grease and wax Asphalt Highest Boiling Point

17 Organization of Petroleum Exporting Countries (OPEC) In 2006 OPEC produced 43% of the world's oil (down from 65% in 1973) OPEC members: Algeria, Ecuador, Gabon, Indonesia, Iran, Iraq, Kuwait, Libya, Nigeria, Qatar, Saudi Arabia, UAE & Venezuela Important Non-OPEC oil producers include Mexico and Canada (oil sand)

18 Barrels of oil per year (billions) ANWR (Arctic National Wildlife Reserves) potential oil supply 14 compared to US projected demand Projected U.S. oil consumption Arctic refuge oil output over 50 years

19 Conventional Oil: Advantages Ample supply for years Low cost Easily transported within & between countries Low land use Technology is well developed Efficient distribution system

20 Conventional Oil: Disadvantages Releases CO 2 when burned Can cause water pollution Pollutes air when produced and burned Nonrenewable. Will need to find substitute in the future Large government subsidies Environmental costs not included in market price Artificially low price encourages waste and discourages search for alternatives

21 Oil Sand Background: Mining Terms Overburden: The layer of material that the mineral resource. Spoil: The material (overburden) that from over a mineral resource. Tailings: The material from a mineral resource (ore). Overburden Mineral Resource Spoil Tailings

22 Oil sand, tar sand -contains bitumen Canada and Venezuela: -oil sand have more oil than in Saudi Arabia Extraction Oil Sand 4 metric tons of overburden removed to produce 1 metric ton of bitumen Each barrel of oil requires Releases _ times as much CO 2 as conventional oil Low net energy yield

23 Video on Oil Sands:

24 Oil Shale Oil shales contain kerogen After distillation: shale oil 72% of the world s reserve is in arid areas of western United States; Lack of water needed for extraction and processing Low net energy yield Video on Oil Shale:

25 Oil Sands and Oil Shale: Advantages Moderate cost (oil sand) Large potential supplies, especially oil sands in Canada Easily transported within and between countries Efficient distribution system in place Technology well-developed (oil sand)

26 Oil Sands and Oil Shale: Disadvantages needed for processing Severe Pet coke waste from refining process (ex. near Chicago and Detroit neighborhoods) Severe water pollution More flammable than traditional crude (recent train fires) Low net energy yield Environmental costs not included in market price

27 Oil Spills - volatile organics can kill many aquatic organisms (especially plankton & larvae), - floating oil coats birds & marine mammals,, - heavy oil sinks to ocean bottom & washes into estuaries where it contaminates crabs, oysters, etc.

28 Exxon Valdez Oil Spill March 24, 1989, Exxon Valdez spilled oil in Prince William Sound Over 1,600 km (1,000 mi) of shoreline was coated Exxon ruled negligent in 1991 federal lawsuit, and paid $1 billion to Alaska in fines Exxon ruled guilty in 1994 lawsuit, and awarded $5 billion in damages to fishing industry, landowners, and AK residents

29 Preventing Oil Spills A may have prevented the Valdez catastrophe All new tankers must have a double hull, and all singlehulled tankers are supposed to be phased out by 2015, but the oil industry is working to weaken these requirements. Oil Protection Act of 1990 was supposed to regulate supertankers, but oil companies have found a way around the law by operating barges instead of tankers

30 Deep Horizon Oil Spill: Gulf of Mexico On April 20 th, 2010, methane in a deep water oil well caused an explosion. For 3 months oil gushed into the deep ocean before being capped An estimated 200 million gallons spilled.

31 Methods of Cleaning-up Oils Clean-up efforts included: Skimming Burning Removal from beaches Sorbents (Pads to absorb oil) Use of dispersants ( ) Booms to contain spill, sorbents and other materials must be disposed of as a hazardous waste.

32 Deep Horizon Oil Spill: Gulf of Mexico Corexit was the primary dispersant used and was highly controversial. Corexit is a carcinogen with the potential to bioaccumulate. The OSHA Materials Safety Data Sheet (MSDS) states: No toxicity studies have been conducted on this product. On May 19 th, the EPA gave BP 24 hours to choose a less toxic dispersant. By July 30 th, about 1.8 million gallons of dispersant, mostly Corexit, had been deployed.

33 Deep Horizon Oil Spill: Gulf of Mexico

34 Deep Horizon Oil Spill Methane: About 200,000 tons of CH 4 were released As of Sept. 2010, most of the methane appeared to be gone. Methane-eating microbes (methanotrophs) are probably responsible Downside:, so waters became depleted.

35 CAFE Standards: Corporate Average Fuel Economy After the 1973 Oil Embargo, the US Energy Policy & Conservation Act of 1975 set standards for the average fuel efficiency for each From , the CAFE standards were 27.5 mpg for passenger vehicles and 20.7 mpg for light trucks/suv s Increases in standards through both the EISA (Energy Independence and Security Act in 2007 and Obama Administration regulations. Increases to average for (new) passenger vehicles by 2025.

36 Natural Gas Natural gas is a mixture of 50 90% methane (CH 4 ), with other hydrocarbons and the toxic gas hydrogen sulfide (H 2 S). When a natural gas field is tapped, propane (C 3 H 8 ) & butane (C 4 H 10 ) gases are removed as liquefied petroleum gas (LPG). Natural gas is typically transported in.

37 Transporting Natural Gas Pipelines extend for hundreds of miles, which can be hazardous Pipelines can also leak into the atmosphere. Natural Gas is also transported in ships and trucks

38 Conventional natural gas is. Russia has largest reserves of conventional natural gas. Unconventional natural gas is found in coal beds, tight sands, dissolved in deep hot water, and frozen on the ocean floor. US has large reserves of unconventional natural gas

39 Fracking: Hydraulic Fracturing New technology uses high pressure water and chemicals injected horizontally into deposits to fracture and release the gas. Environmental Concerns: Marcellus Shale is a major deposit of natural gas in the NE (Pennsylvania, New York) Videos on Fracking:

40 Natural Gas: Advantages CO 2 emissions per unit energy produced is for natural gas compared to other fossil fuels. than other fossil fuels Easily transported by pipeline Low land use Ample supplies

41 Natural Gas: Disadvantages Nonrenewable resource Releases CO 2 when burned Environmental costs not included in price Difficult to transfer from one country to another Can be shipped across ocean only as highly explosive LNG Groundwater pollution from fracking

42 Coal Coal is a fossil fuel, produced from the buried remains of swamp plants that died during the Carboniferous period (geologic era ending 286 million years ago). Stages in the formation of coal over millions of years. Note the three types of coal.

43 Coal Sources & Uses Largest reserves of coal are in United States, the former Soviet Union countries, and China. Coal provides about 25% of the world's commercial energy (22% in U.S.) Used to generate 64% of world's electricity (57% in U.S.) Used to make China gets from coal, largest user.

44 Waste heat Coal bunker Turbine Generator Cooling loop Cooling tower transfers waste heat to atmosphere Pulverizing mill Boiler Condenser Filter Stack Toxic ash disposal

45 Mountaintop Removal Mining

46 Mercury Emissions from Coal Coal is naturally contaminated with mercury, which is released when it is burned. Coal-burning power plants and industrial boilers are the greatest contributor to mercury pollution.

47 Air Pollution from Coal: Acid Rain and Soot Coal contains sulfur and nitrogen impurities. Sulfur dioxide (SO 2 ) and nitrogen oxides (NO x ) are emitted from coal burning. These molecules react in the atmosphere to form. 2/3 of all SO 2 and ¼ of all NO x comes from electricity generated by fossil fuels (especially coal). East coast uses a greater percentage of coal and has more acid rain.

48 Recent NASA Images of China s Air Pollution ews/wp/2013/01/15/unbelievable-photos-ofhow-bad-beijings-air-has-gotten/

49 Air Pollution from Coal: Soot Carbon soot both contributes to global warming and is a harmful air pollutant (fine particulate matter.) Methods of Reducing Air Pollution: Videos on Coal:

50 Scrubbers can reduce Sulfur Dioxide Emissions

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52 TRADE-OFFS Coal Advantages Ample supplies ( years) High net energy yield Low cost Well-developed technology Air pollution can be reduced with improved technology Disadvantages Severe land disturbance, air pollution, and water pollution Severe threat to human health when burned Environmental costs not included in market price Large government subsidies High CO 2 emissions when produced and burned Radioactive particle and toxic mercury emissions

53 Conversion of solid coal to -Synthetic natural gas (SNG) by coal gasification - Methanol or synthetic gasoline by coal liquefaction Advantages Large potential supply Synthetic fuels Disadvantages Low to moderate net energy yield Higher cost than coal Vehicle fuel Moderate cost Requires mining 50% more coal Environmental costs not included in market price High environmental impact Large government subsidies Lower air pollution than coal when burned High water use Higher CO 2 emissions than coal

54 Methane Hydrates Methane hydrates are methane molecules (CH 4 ) encased in an ice lattice Stable only at Boils off at STP, and is extremely volatile Not currently safe methods to extract Videos on methane hydrates: