Transcript Chapter 12
Chapter 12 Part 1 STNT – 35 Do the Math – page 321, 324 Do the Math – Calculating Electricity Supply Questions – Science Applied pg. 376-7 Internet activity – Vampire Appliances Cost Chapter 12 Nonrenewable Energy Resources All Energy Use Has Consequences 1. What events of the 1960s led to the first Earth Day in 1970? 2. What are the causes of oil spills? 3. Give an example for each. 4. What are the risks associated with coal? 5. Why is natural gas called the “clean” fossil fuel and why is it not “clean”? 6. What are the environmental risks with natural gas extraction? Spill Brings “gaps in knowledge” To Light 80,000 chemicals in the U.S. cataloged by the government regulators. The health risks of most of these are unknown. January 9,2014 Licorice-smelling chemical leaked from an old storage tank into the Elk River in West Virginia. 4-methylcyclohexane methanol. Chemicals in U.S. are generally treated as innocent until proven guilty. Forms of Energy • Chemical - Stored in chemical bonds between atoms • Electrical - Result of the movement of electrons • Electromagnetic - Energy that travels in waves • Kinetic - Energy due to motion • Potential - Energy stored • Mechanical • Potential and kinetic energy present in a mechanical system such as a turbine or generator • Nuclear • Stored energy in nucleus of atom released by splitting the atom – fission or combining atoms fusion. • Thermal • Energy content related to heating effects Nonrenewable Energy • Nonrenewable energy resources • Types • Fossil fuels • Nuclear fuels. • What are the “take-home points of this graph? 2008 Energy Units • Basic unit is the joule (J) • GJ – gigajoule • 1 billion joules • 1 X 109 • EJ – exajoule • 1 billion gigajoules Energy Consumption • Greatest total energy consumption? • Greatest per capita energy consumption? • Compare total/per-capita energy use of the China and India. • Types of energy used in developing vs developed countries: Energy Use Commercial energy sources Those that are bought and sold Developed countries Subsistence energy sources Those gathered by individuals for their own use such as wood, charcoal and animal waste. Developing countries Energy demand increases societies change the type of fuels they use. Patterns of Energy Use in U.S. Inputs Outputs “take home” points from graph Energy U.S. and Global • Types • Comparison • Explanation U.S. U.S. Global The top 15 countries extract 78% of the world's fossil fuels, and only four of the top 15 are developed countries. Imports and Exports • U.S. produces 70% of the energy it uses. • 30% from other countries – mostly oil • Energy Use Varies • Energy users most to least: Energy Types and Quality • Certain forms of energy are best suited for particular purposes. • Transportation - Gas or diesel – liquid energy • High energy to mass ratio • Speed to provide and cut off the energy • Energy efficiency • Efficiency in the process to obtain the fuel. • Efficiency in the process that converts the fuel to work. • Energy Laws 35% effective 2/3 lost during transformation/ash Inefficiencies in Coal Extraction and Use EROEI Energy Return On Energy Investment How much energy from an energy source for each unit of energy expended on production EROEI = __ energy from fuel____________ energy invested to obtain the fuel In order to obtain 100J of coal energy, 5J of energy is expended. EROEI = ___________ Coal Cost to extract the coal Cost to build the equipment to extract the coal Building the power plant Disposing of the waste from the power plant Science Applied pg. 376-7 1. Why is corn-based ethanol a big business? 2. Does ethanol reduce air pollution? 3. What is the difference between a modern carbon and a fossil carbon? 4. Compare the EROEI of ethanol to coal. 5. What are the environmental negatives to using corn for ethanol? 6. What are the alternatives to corn ethanol? 1. Most efficient? 2. Least efficient? 3. What happens to the efficiency when you put 4 people in the car? 4. What is the most common number of people in a car? 5. Public vs. Private transportation – pros and cons. Do the Math Imagine you have unlimited time and you need to go from Washington, DC to Cleveland, Ohio – roughly 600 km. Use table 12.1 and calculate the amount of MJ of energy for each mode. Air = Car = Train = Bus = If a gallon of gas contains 120MJ, how many gallons does it take to make the trip by car? Overall Fuel Efficiency of U.S. Automobiles 30% of energy used for transportation Light trucks – SUVs, minivans, pickups – ½ auto sales. Fuel efficient vehicles?? Café Standards • Corporate Average Fuel Efficiency. • Regulations enacted by Congress in 1975, after the Arab Oil Embargo. • Intended to improve the average fuel economy of cars and light trucks. • Manufacturer must pay a penalty $5.50 per 0.1 mpg less than standard, multiplied by the manufacturer's total production for the U.S. Gas Guzzler Tax Applies to the sales of vehicles with estimated gas mileage below certain specified levels. 1980, the tax was $200 for a fuel efficiency of 14-15 mpg. 1985 increased to $1800. 1980, the tax was $550 for fuel efficiencies of 13 mpg and below, and was changed in 1986 to $3,850 for ratings below 12.5 mpg. Only applies to passenger cars. Trucks, sport utility vehicles (SUV), and minivans are not covered because these vehicle types were not widely available in 1978 and were rarely used for non-commercial purposes. The tax is collected by the Internal Revenue Service (IRS) and normally paid by the manufacturer or importer. • 1992 Clinton “We won’t push to tighten the efficiency standards if you will agree – with federal money– to research super-energy-efficient vehicles. • More than a decade later, they had produced cars that could go 80 miles on a single gallon of gas. • But there was never any legally enforceable requirement to actually produce these cars. And the automakers didn’t. • They said using the super-light-weight materials they had developed would add $7,000 to $10,000 to the cost of a family sedan. • President George W. Bush abandoned that program • He launched a multi-decade research program to develop a car propelled by a hydrogenpowered fuel cell. • With global warming environmental activists want to tighten CAFE standards. • Opponents, including automakers, argue that such a move would make cars too expensive and, because they would be lighter and smaller, more dangerous. Starting in 2011 the CAFE standards are newly expressed as mathematical functions depending on vehicle "footprint", a measure of vehicle size determined by multiplying the vehicle’s wheelbase by its average track width. 2012 Honda Fit with a footprint of 40 sq ft must achieve fuel economy 36 mpg. Ford F-150 with its footprint of 65–75 sq ft must achieve CAFE fuel economy of 22 mpg. CAFE has separate standards for "passenger cars" and "light trucks", despite the majority of "light trucks" actually being used as passenger cars. Electricity Coal, oil, natural gas and the sun are primary sources of energy Electricity is a secondary source of energy, an energy carrier. Electricity is clean at point of use but can be produced by burning fossil fuels and pollutants are released at location of production. U.S. 40% of energy is used to produce electricity but only 13% is available at the end use. Electricity Generation Generator • Consists of copper wire coils and magnets. • As the turbine spins, the magnets in the generator to pass over the wire coils. • This generates a flow of electrons through the copper wire producing alternating current that passes into electrical transmission lines. Energy Efficiency Most coal burning power plants are about 35% efficient. Capacity- maximum electrical output 500 MW capacity = 500 MW of electricity Multiply by 24 for MWh – convert to kWh Capacity factor The fraction of the time the plant is operating. Maintenance, refueling, repairs Do the Math – Calculating Electricity Supply 1. A typical home in U.S. uses approximately 900 kWh of electricity per month. On an annual basis this would be ___________ 2. How many homes can a 500 MW power plant with a 0.9 capacity factor support? Cogeneration • Cogeneration • Using fuel to generate electricity and produce heat. • Combined heart and power – 90% efficient • Steam used for industry to heat buildings can be used to turn turbine for electricity. Energy Used for Electricity in U. S. • Primary source for electricity? • Why? • Not used for electricity? • Why not? Vampire Appliances Appliances that consume electricity even when they are turned off by going into a standby mode. Top 5 energy vampires Computers, modems, routers Instant-on TVs Surround sound systems Cable or satellite TV boxes Household items with a clock – microwave, DVD planer Vampire Appliances Identification Has an external power supply Has a remote control Has a continuous display such as a clock Charges batteries These can be connected to power strips and then turn off the power strip and they will not consume electricity. Internet Activity • www.savewithsrp.com/advice/appliance/energyv ampires.aspx • Scroll to bottom – How much do vampire appliances cost. • Enter the number of each device you have – total cost at bottom • Determine the annual cost of your vampire appliances • National Appliance Energy Act • Set minimum efficiency standards for numerous categories of appliances. Chapter 12 Part 2 STNT - 35 Three separate charts – coal, oil, natural gas 2 columns for each – Advantages, Disadvantages Complete before coming to class Coal Increase in time and pressure = denser, more carbon, more energy per gram and more expensive • Coal – a solid fuel formed from plant remains. Lignite and Anthracite have lowest sulfur content. Sub-bituminous and bituminous have the highest. Producers • Largest producers • China, then U.S. • Largest coal reserves • U.S. • Russia • China Advantages and Disadvantages of Coal Advantages • Easy to exploit by surface mining. • Energy-dense. • Plentiful. • Economic costs are low. • Easy to handle and transport • Needs little refining. • Stable, non-explosive, no spill dangers • U.S. government subsidies keep prices low Disadvantages • Release impurities into air when burned - particulates. • Contains trace metals mercury, lead, and arsenic. • Combustion increases SO2 and CO2 into atmosphere global climate change. • More CO2 than oil/natural gas. • Ash is left behind. Ash holding ponds. • Mining produces runoff. • Subsurface – more technology and costs more. • Transport by trucks. Scrubbers • Equipment that takes out the harmful substances forming a neutral compound in the scrubber. • Eliminated in waste sludge. Sulfur Dioxide Scrubbers • Coal chemicals other than carbon, including sulfur. • When coal is burned, the sulfur combines with the oxygen SO2, which is emitted into the air through a plant’s stacks. • In atmosphere: • SO2 + H2O H2SO4 • A scrubber works by spraying a wet slurry of limestone into a large chamber where the calcium in the limestone removes the sulfur. Carbon Sequestration • Carbon capture and storage. • Capture of CO2 from power plants or other industrial processes. • Transport of the captured and compressed CO2 (usually in pipelines). • Underground injection and geologic storage into deep underground rock formations. These formations are often a mile or more beneath the surface and consist of porous rock that holds the CO2. Overlying these formations are impermeable, non-porous layers of rock that trap the CO2 and prevent it from migrating upward. • “Confined aquifer for CO2” Surface Mining Control and Reclamation Act SMCRA - is the primary federal law that regulates the environmental effects of coal mining in the United States. SMCRA created two programs: one for regulating active coal mines second for reclaiming abandoned mine lands. Petroleum • A mixture of hydrocarbons, water, and sulfur that occurs in underground deposits. • Formed from the remains of ocean-dwelling animal remains esp. phytoplankton. • Fluid nature for mobile combustion. • Countries with the most petroleum: Petroleum Flaring is the burning off of the natural gas to prevent explosions. • Flows out like artesian well. • Transported by pipeline or tanker. • Often petroleum is covered by natural gas (methane). • May also be mined Petroleum • Crude oil • Liquid petroleum removed from the ground. • Refineries • Convert crude oil into many compounds by heating. • Each product boils at a different temperature. OPEC Organization of Petroleum Exporting Countries • Members include major oil exporting companies such as Saudi Arabia, Nigeria, Venezuela and others. • Price of energy is driven by the principle of supply and demand – items scarcer are more expensive. • OPEC regulates the price of oil for its members. • Now with increase in oil production in U.S. and Canada, OPEC has lost some of its power to control oil prices. Advantages and Disadvantages of Petroleum Advantages Disadvantages Convenient to transport and use Relatively energydense Releases carbon dioxide – atmosphere when burned Possibility of leaks when extracted and transported Cleaner-burning than coal – less CO2 than coal. • Releases sulfur, mercury, lead, and arsenic when burned. • 85% of oil entering marine waterways comes from runoff U.S. Subsidies keep prices low Laws • Energy Policy and Conservation Act • Result of the 1973-74 oil embargo where oil from OPEC to the U.S was cut off. • The United States established policy to establish a reserve of up to 1 billion barrels of petroleum, Strategic Petroleum Reserve (SPR). • Energy Policy Act • Act provides loan guarantees for entities that develop or use innovative technologies that avoid the by-production of greenhouse gases. • Increases the amount of biofuel that must be mixed with gasoline sold in the United States. Keystone Pipeline • Pipeline system to transport petroleum from Alberta, Canada , Montana and North Dakota to refineries in Texas on Gulf Coast. • Concerns • Oil spills along the pipeline – polluting air and water supplies (crosses the Ogallala Aquifer) • Extraction of tar sands creates more greenhouse gases. • Proponents • Decrease U.S. dependency on foreign oil. ANWR Artic National Wildlife Refuge • Pipeline for oil from Alaska to tankers to take oil to continental U.S. • Concerns • Might melt permafrost. • Interfere with species – mating and habitats. Oil, Tar, Bituminous Sands • An unconventional petroleum deposit. • Naturally occurring mixtures • 90% of sand, clay, water • 10% saturated with a dense and extremely viscous form of petroleum, bitumen. (Tar) • Natural bitumen deposits are reported in many countries but in extremely large quantities in Canada. Problems with Oil Sands • Squeezing oil out of tar sand uses • 2 to 4 tons of tar sand and • 2 to 4 barrels of water to produce a single barrel of oil. • Enormous shovels carve out open pits in the tar sands. • Oil and sand is taken to a processing facility. Processing Facility • Tar sand is combined with water to form a slurry. • Sand sinks to the bottom of the mixture while the bitumen floats to the top. • Bitumen is extracted, the run-off is piped into large, stagnant tailing ponds of sand, water, and bitumen impurities. • Process releases 3X more CO2 than processing petroleum. Natural Gas Exists as a component of petroleum in the ground Lighter than oil, lies above oil in petroleum deposits. Also in gaseous deposits separate from petroleum. Contains 80 to 95 percent methane and 5 to 20 percent ethane, propane, and butane. Uses: Electricity Industry Manufacture fertilizer Cooking, heating LPG Liquefied Petroleum Gas Natural gas in a liquid form Disadvantages Less energy dense Advantages Accessible everywhere Uses In place of natural gas Barbeque grills Portable heaters Hydraulic Fracturing “Fracking” • It is a process of pumping millions of gallons of water along with a mix of sand and chemicals deep into the Earth to break apart the rock below and free the gas locked inside it. Natural Gas Field Fracking • Drilling with water, sand and “proprietary” chemicals. • Problems/Solutions with water: • Natural gas is found in arid areas. • Process requires millions of gallons of clean water. • 20% return of water but contaminated with drilling chemicals and heavy metals. • Previously contaminated water was injected in deep wells in earth. • Charge the water separating particles which fall to the bottom as solids and taken to landfills. • Some companies frack without water • Evidences of increase in earthquakes in areas of fracking. • Many occurring in areas of few to no earthquakes previously. • Increase in some areas from 20 to 100 a year. • Thought to be result of injections wells for contaminated water. Video • Animation of Hydraulic Fracking (6:37) • http://www.youtube.com/watch?v=VY34PQUiwOQ • http://www.youtube.com/watch?v=CrpqrpOuLsE Natural Gas Advantages Disadvantages • Contains fewer • When unburned, impurities and therefore methane escapes into emits almost no sulfur the atmosphere. dioxide or particulates. • Methane is 25X more potent than CO2 • Emits only 60% as much • Exploration of natural carbon dioxide as coal. gas has the potential of contaminating groundwater. Liquefied Coal • CTL – coal to liquid • Advantages • Because there is so much coal in U.S. this could eliminate U.S. dependency on oil. • Can be used for transportation. • Disadvantages • Expensive. • Greenhouse gas emissions more than twice that of oil. Chapter 12 - Part 3 – STNT 35 Do the Math Chart – Advantages and Disadvantages of Nuclear Energy Read and take notes or Print and highlight Deadly Meltdown – Chernobyl Yucca Mountain Nuclear Waste Repository Energy Use and Intensity • Total energy use: • Per capita energy use: • Energy intensity: • “Take-home point”: The Hubbert Curve • M. King Hubbert • Point at which world oil production would reach a maximum (peak point) and the point at which we would run out of oil. • Difference between upper and lower estimates? • Where are we on the graph? “Take-home point”? The Future of Fossil Fuel Use • If current global use continues, we will run out of conventional oil in less than 40 years. • Coal supplies will last for at least 200 years, and probably much longer. • Rather than “When will we run out of oil?” We should ask “How can we transition away from fossil fuels before their use causes further problems.” • Concerns • Cost of fossil fuels. • Influence of CO2 on global climate change. Isotopes • Atoms of the same element but have different numbers of neutrons. • Additional neutrons will add: • The atom will be affected: Nuclear Changes • Changes in matter when the nuclei of certain isotopes change. • Radioactive isotopes • Isotopes that have become unstable due to their extra neutrons. • Release protons and neutrons from the nucleus of the atom – Radioactive decay. Radioactive Decay • Spontaneous release of material from the nucleus. • Changes the radioactive element into a different element. • Example • Uranium-235 decays to form thorium-231 • The decay of Uranium-235 releases a great deal of energy that can be captured as heat. • How do nuclear power plants use this heat? Half-Life • Way to measure rate of radioactive decay of a quantity of a radioactive element. • The time it takes for one-half of the original radioactive parent atoms to decay. • Identifiable by counting the number of protons and neutrons to see what the element has converted into. Do The Math 1. The half-life of radon gas is approximately four days. Four weeks after the introduction of radon into a sealed room, the fraction of the original amount remaining is closest to: A. ½ B. 1/8 C. 1/32 D. 1/64 E. 1/128 Do The Math 2. A sample of radioactive waste has a halflife of 10 years and an activity level of 2 curies. After how many years will the activity level of this sample be 0.25 curie? A. 10 years B. 20 years C. 30 years D. 40 years E. 80 years Nuclear Changes: Fission • Nuclear fission: • Neutron released due radioactive decay hits another atom. • This collision releases barium, krypton and 3 neutrons. • Practical application • Nuclear power plants • Uranium - half-life of 703.8 million years. Nuclear Reactors Production of Electricity Uranium: 1 g uranium 235 = 2 – 3 times more energy 1g coal Containment structure – Fuel rods, control rods, steam generator Process Control rods - meltdown Open Pit Mining for Uranium • Removes near-surface deposits • Requires the removal of rock/soil to access the ore. 40 tons of waste for each ton of ore. • Mining companies are not required by law to contain and treat waste rock. • Seepage from waste rock may contain traces of uranium,, heavy metals, and acids. • Release of dust and radon gas. Rainwater runoffs require the development of large evaporation ponds for storage and expensive treatment facilities for processing. • Extract and concentrate the uranium. • Nuclear power plants require U235 however most ore is U238 which does not fission as easily. • U238 must be enriched to increase concentration. Production from Mines in tonnes Country 2013 Kazakhstan Canada Australia 22451 9331 6350 Niger 4518 Namibia Russia Uzbekistan USA 4323 3135 2400 1792 Nuclear Energy in the U.S. • 20% of electricity generated in U.S. is from nuclear energy. • Construction of new power plants: • Expensive • Public protests, legal battles • Uncertainty about appropriate locations for radioactive waste disposal. Nuclear Energy in Florids 5 nuclear reactors 3 locations • Progress Energy's Crystal River plant north of Tampa • Florida Power & Light's St. Lucie southeast of Ft. Pierce • FPL's Turkey Point miles south of Miami The US is the world's largest producer of nuclear power. • 100 Nuclear Plants in U.S. • 3 under construction • 437 Nuclear Plants World Wide • 71 under construction World Wide Radioactive Waste • Types of Radioactive Waste • High-level radioactive waste • Low-level radioactive waste • Uranium mine tailings • Disposal of all waste is regulated by the government: • Low Level Radioactive Policy Act • All states must have facilities to handle low level radioactive waste. Nuclear Waste Disposal Nuclear fuel fist cools in a waterfilled pool and then transferred to massive casks that sit on land. Must be stored in highly secure locations because of danger to living organisms and possible use by terrorists groups. By law the federal government is responsible for nuclear fuel disposal. Advantages and Disadvantages of Nuclear Energy Advantages Disadvantages No air pollution is Possibility of accidents produced Countries can limit their Disposal of the need for imported oil radioactive waste Pollutants are produced in the mining and transport of uranium Nuclear Accidents 3 Mile Island Power Station http://www.youtube.com/watch?v=7Od0aJXyM8k Worst nuclear disaster in U.S. Operator did not notice that a cooling water valve had been closed the previous day. Lack of cooling water around the reactor core. Reactor core overheated and was severely damaged. Unknown amount of radiation was released from the plant to the outside environment. No documented increase in adverse health effects. Reactor has not been used since. Chernobyl • Accident occurred during a test of the plant when, • in violation of safety regulations, operators deliberately disconnected emergency cooling systems and removed control rods. • The nuclear reactions continued without control, the plant overheated, explosions and fire damaged the plant beyond use. • Wind blew radiation across Europe where it contaminated crops and milk from cows grazing on contaminated grass. Results of Chernobyl Thousands of cases of thyroid cancer, most nonfatal caused by absorption of radioactive iodine emitted. http://www.youtube.com/watch?v=VuiWFVamQWg Capping Chernobyl Site • Manufactured in one area then moved on tracks over the building containing the destroyed reactor. • Then the reactor will be dismantled and the radioactive waste disposed of. • Taller than the statue of Liberty. Changes in Chernobyl Birds with smaller brains. Increase in spiders, decrease in butterflies. Dead leaves and trees on the forest floor are not decaying – even after almost 30 years. Changes in color patterns on some insects. Fukushima Nuclear Disaster • 2011 when plant was hit by a tsunami. • 2nd largest nuclear disaster to Chernobyl. • No short term radiation exposure fatalities. • Expected future cancer deaths – leukemia, thyroid, breast. Fukushima • Nuclear disaster was "manmade" . • Direct causes were all foreseeable. • Plant was incapable of withstanding the earthquake and tsunami. • Failed to meet the most basic safety requirements, such as assessing the probability of damage, preparing for containing collateral damage from such a disaster, and developing evacuation plans. Nuclear Waste • Nuclear Waste Policy Act - 1982 • Establish a site to identify and construct and • • underground repository for spent nuclear reactor fuel and high-level radioactive waste from federal defense programs. Yucca Mountain in Nevada • Project was defunded by Nevada Senator and Senate Majority Leader Harry Reid in 2010. Atomic Energy Act • Provides for the development and regulation of the uses of nuclear materials and facilities in the U.S. Yucca Mountain • Deep storage facility for spent nuclear fuel and other radioactive waste near Nevada test site in Yucca Mountain ridge. • Approved in 2002 and terminated in 2011. • Terminated for political, not technical or safety reasons. Nuclear Waste Train • Plans for trains to haul radioactive waste from nuclear power plants to disposal sites. • 150 ton casks filled with used radioactive nuclear fuel. • Expected to be used 8 times a year. • Requires buffer cars to maintain a safe distance between crew and radioactive cargo. • Responsibility of U.S. Nuclear Regulatory commission and Department of Transportation. Nuclear Fusion • Promising, unlimited source of energy, but the difficulty is containing the heat produced. • Same reaction that powers the sun and other stars. • Occurs when lighter nuclei are forced together to produce heavier nuclei producing a great amount of heat. • For electricity • Two hydrogen isotopes fusing together into a helium atom. • Small amount of mass is lost and huge amount of energy is liberated. • A reactor for this will need to heat materials to temperatures 10 times the temperature in the core of the sun.