Energy and Resources
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ENERGY AND RESOURCES Chapters 23, 19, 20, 21 WE WERE WARNED: TOMORROW’S OIL CRISIS Part 1 (10 minutes): http://www.youtube.com/watch?v=1vPi7SEzz Wg Minerals and Mining CHAPTER 23 MINERAL RESOURCES Rocks provide the minerals we use Mining is used to obtain minerals Fossil fuels, groundwater?? Most minerals are in low concentrations, so scientists attempt to find concentrated sources of minerals before mining begins Metals can be extracted within ore Rocks are a solid aggregation of minerals Minerals are naturally occurring solid chemical elements or compounds Metals are elements that are typically lustrous, opaque, malleable conductors Most metals are not found in a pure state, but are found within an ore (a grouping of minerals) Common economically valuable metals: copper, iron, gold, aluminum Metals need to be processed to separate them from the ore and make them ready for use Chemical or physical removal Smelting Harmful byproducts? Tailings MINERAL RESOURCES We also mine/use many non-minerals Construction Materials: Sand, gravel, Fertilizers: phosphates, Other economic value: limestone, salt, potash, diamonds Fuels: Uranium, Fuels that are not technically minerals: coal, petroleum, natural gas, oil sands, oil shale, methane Conflict over mining products “blood diamonds” MINING METHODS Mining makes a huge contribution to the economy $57 B in raw materials (2009) $454 B in processed materials (2009) 1.2 million jobs Mining exerts a huge impact on the environment! Strip mining Subsurface mining Open Pit mining Placer mining Mountaintop mining Solution mining Ocean mining https://www.youtube.com/wa tch?v=ioqauAoZwVY TYPES OF MINING (DESCRIPTIONS AND IMPACTS) TYPES OF MINING (DESCRIPTIONS AND IMPACTS) TYPES OF MINING (DESCRIPTIONS AND IMPACTS) TYPES OF MINING (DESCRIPTIONS AND IMPACTS) TYPES OF MINING (DESCRIPTIONS AND IMPACTS) TYPES OF MINING (DESCRIPTIONS AND IMPACTS) CAN MINING IMPACTS BE REGULATED OR REVERSED? Mining companies are required to restore sites when finished (in the United States) Reclamation Removal of buildings and structures Soils: biotic potential? Waters: drainage and reclamation Policies General Mining Act of 1872 Hardrock Mining and Reclamation Act of 2009 Mineral Leasing Act of 1920 SUSTAINABLE MINERAL USE Non-renewable resource in limited supply Economically recoverable mining Technically recoverable mining How long will deposits last? Discovery of new reserves New extraction technologies Changing pressures from society, technology, and consumers Recycling Gold versus Platinum E-waste THERE’S NO TOMORROW http://www.youtube.com/watch?v=VOMWzjrRiBg 0:00-7:10 Introduction Fossil Fuels, Their Impacts, and Energy Conservation CHAPTER 19 SOURCES OF ENERGY Since the Industrial Revolution, our main source of energy has been: Sun Photosynthesis Fossil Fuels Fossil Fuels (Coal, Oil, Natural Gas) High energy content allows for Used for Shipping Burning Storing Transportation Heating/Cooking Electricity (secondary form of energy that can be transported over long distances) Others Geothermal Tides Nuclear Energy Biomass Solar, Wind GRAPH THE GLOBAL CONSUMPTION OF FOSSIL FUELS OVER THE PAST 50 YEARS FOSSIL FUELS Come from fossils Depends upon Starting material Temperature and pressure Anaerobic decomposers (Aerobic versus Anaerobic decomposition) Time Because of all these factors, deposits for FF are unevenly distributed Developed Nations consume more than Developing Nations (20% by United States) Oil •Saudi Arabia (20%) •Venezuela (13%) Natural Gas •Russia (24%) •Iran (15.8) Coal •United States (28.9%) •Russia (19%) IT TAKES ENERGY TO MAKE ENERGY Net energy expresses the difference between energy returned and energy invested EROI (Energy Returned on Investment) EROI= Energy returned/Energy invested The higher the EROI ratio, the more energy we get per unit we invest Oil and natural gas were 100:1 in 1940, 30:1 in 1970 and are about 5:1 now….WHY? COAL Most abundant fossil fuel Hard, dark substance that form from organic matter (almost always woody plant matter) that gets compressed under high pressure where little or no decomposition has taken place Starts as peat and them becomes coal Deposition mostly occurred 300-400 million years ago in swampy environments The high pressure of formation results in a dense, solid carbon structure Has been used by humans for thousands of years, but demand began increasing with the start of the steel industry (1875) Provides 50% of electrical energy in the US China (39%) and US (16%) are the primary producers China (39%) and US (15.5%) are the primary consumers COAL We extract coal by Types of coal (changes in water, carbon, and energy content) Strip mining Subsurface mining Mountaintop removal mining Lignite (least compressed=less carbon=less energy per unit volume) Sub-bituminous Bituminous Anthracite (most compressed=more carbon=more energy per unit volume) Coal can also vary in its impurities = important for reducing pollution We get energy from coal by Combusting (burning) coal to convert water to steam which turns a turbine NATURAL GAS Versatile and clean-burning compared to other fuels (emits ½ the carbon or coal and 2/3 the carbon of oil) Consists of methane and other hydrocarbons Uses: heating our homes, electricity At low temps (in a liquid state) it can be shipped long distances Russia (21%) and US (19%) are the largest producers US (21%) and Russia (15%) are the largest consumers At current rates of use, we have about 60 years left NATURAL GAS Formation Biogenic gas: shallow, anaerobic decomposition swamp gas gas from landfills Thermogenic gas: deep underground compression Kerogen: can form natural gas and crude oil, most gas is found above oil or coal Most commercially extracted gas is thermogenic Coalbed methane: commonly leaks out during mining processes Miners now try to trap and use this gas or burn it off (called flaring) FRACKING Gas naturally moves upwards because of pressure underground and its low molecular weight Because we have already mined so much gas, many sites now require gas to be pumped to the surface with a “horsehead pump” Fracturing techniques (known as “fracking”) break into rock formations using water under high pressure, hold the crack open with sand or glass beads, and extract the gas This process bring up many concerns! OFFSHORE DRILLING Natural gas (13%) and oil (1/3) come from the Gulf of Mexico and southern California coast Drilling into the seafloor on the continental shelf (this is where more of the remaining resources probably are) Platforms must withstand wind, waves, currents Some actually float Potential Issues? Moratorium on offshore drilling lifted in 2008 and then expanded in 2010 Deepwater Horizon Backtracking and stoppage of new approvals OIL/PETROLEUM Oil is our most used fuel, accounting for 35% Used since 1854 (Pennsylvania) Crude Oil (a sludgelike liquid) usually forms 1.5-3km below the surface from dead plant material trapped under marine waters millions of years ago (just like natural gas) Globally, 200 gallons are used per person Use has increased 15% in the last decade and does not show signs of slowing (US, China, India) Russia (12%) and Saudi Arabia (12%) are the largest producers (followed by US at 10%) United States (22%) and China (10%) are the largest consumers HOW DO WE GET OIL? Geothermal heating allows crude oil to migrate up through rock pores and collect in layers Geologists search for oil by drilling, using seismic surveys, and mapping underground rock formations These methods have estimated that 11.6-31.5 billion barrels of oil lay beneath the Arctic National Wildlife Refuge, of which 4.3-11.8 are recoverable currently Proven Recoverable Reserve Technology determines what can be extracted Market Price determines how much will be extracted • Drilling extracts oil • Exploratory Drilling • Primary Extraction: Oil rises on its own from pressure • Secondary Extraction: 2/3 of oil may remain trapped, solvents and/or water and steam are used • $$$$$ • Not everything can be removed with our current technology USES OF OIL Petroleum products Separation of components of crude oil (based on size of hydrocarbon chains) must take place at a refinery Heating, cooking, transportation, asphalt, plastics, lubricants, fabrics, pharmaceuticals, fertilizers, pesticides ARE WE RUNNING OUT OF OIL? Estimates are that we have used around ½ of the world’s oil reserves Reserves-to-production ratio (R/P ratio) Total remaining reserves/annual production rate 1.2 trillion barrels/30 billion barrels = 40 more years When should we start to worry? When we run out “Peak Oil”……now Hubbert’s Peak Should we worry? Suburbs as slums of the future Conservation of energy and alternative energy soruces OIL SANDS (TAR SANDS) Sand and clay that contain 1-20% bitumen, a thick form of petroleum Too thick to extract conventionally, so strip mining is often used at the surface Deposits more than 75m below ground are removed using steam injection or chemical solvents After extraction, it must be sent to a refinery that can upgrade the fuel by adding hydrogen and removing carbon ¾ of deposits are found in Venezuela and Alberta (may almost as much in Canada as oil in Saudi Arabia) OIL SHALE Sedimentary rock filled with kerogen (organic matter) that can be processed to produce liquid petroleum Forms through the same process as oil, but not buried deeply enough Mined through strip mining or subsurface mines It can be burned like coal or baked to extract liquid petroleum 40% of world reserve is found in US west High fuel prices are attracting people to oil shale METHANE HYDRATE Found in sediments on the ocean floor Is stable at these conditions (temperature/pressure) Formed by anaerobic decomposition and thermogenic formation below the surface There are immense amounts available, but we do not know how to extract them safely Release of gas that could cause landslides/tsumani/global warming DRAWBACKS OF ALTERNATIVE FUELS 1. Low EROI 2:1 or 3:1 for oil shale 5:1 for crude oil 2. Environmental impacts 3. Strip mining that devastates landscapes Pollution of waterways Non-recovered areas Emissions Carbon dioxide, methane, air pollutants IMPACTS OF FOSSIL FUELS Pollution Air: Irritants, carcinogens, asphyxiation, poisons, photochemical smog, bioaccumulation Water: Mostly non-point source problem, although we usually hear about the point source problems in the news Drive climate change Exxon Valdez (1989) Cars, homes, industry, gas stations ….. All create runoff that can contaminate waterways and groundwater (drinking water) Retired carbon from long-term reservoir underground and release it into the air Carbon from the fuel combines with oxygen in the air to form Carbon Dioxide Methane is also a powerful greenhouse gas Alters the environment Acid drainage from coal mining Road networks Infrastructures SOLUTIONS? Clean coal technologies Techniques that aim to remove chemicals during the process of generating electricity from coal Carbon capture and carbon storage (sequestration) Scrubbers Dry coal Gasification (syngas) Capturing emissions, converting the gas to a liquid and then storing it in the ocean or underground in rock Mattoon, Illinois Will it stay underground? Will it trigger earthquakes? Will it contaminate groundwater? Will it acidify the ocean? Will it prolong our dependence on diminishing fossil fuels? Directional Drilling ISSUES Political Issues National can become dependent on foreign energy OPEC (Organization of Petroleum Exporting Countries) Economic Issues Supply and prices can change economies of nations Strategic Petroleum Reserve Social Issues Local people may or may not benefit from reserves CONVERSION TO RENEWABLE ENERGY? Option 1: Use it until its gone Option 2: increase funding to develop energy alternatives to start a rapid shift Option 3: middle group, reduce our dependence gradually Energy efficiency: get more and use less Energy conservation: use less Cars Café Standards (corporate average fuel efficiency standards) Low taxes on gas in US Cash for Clunkers Personal choice Increased efficiency Cogeneration THERE’S NO TOMORROW http://www.youtube.com/watch?v=VOMWzjrRiBg 7:10-12:01 Oil, Coal, Natural Gas Conventional Energy Alternatives: Nuclear energy, bioenergy, hydroelectric power CHAPTER 20 CONVENTIONAL ENERGY ALTERNATIVE Play a minor yet substantial role in energy and electricity budgets today Fuelwood and Biomass= 10% Nuclear= 6% Hydropower= 2% Less impact that fossil fuels, but more than renewable alternatives Growth in use is slower than with fossil fuels NUCLEAR POWER What’s its reputation? No air pollution Radioactive waste Accidents Commonly used in US (20%), France (76%), and Japan How does it work? Fission (splitting of atoms) releases nuclear energy Energy (heat, light, radiation) is converted into thermal energy and use to generate electricity Must use large, heavy atoms like uranium-235 (which is not a renewable resource) NUCLEAR POWER If not controlled, the chain reaction of nuclear fission would start a positive feedback loop releasing enormous amounts of energy (like an atomic bomb) Nuclear reactors control this reaction inside power plants Process: -Mining: Only 1% of naturally occurring uranium is U235, so the more common U238 must be processed to be at least 3% U235 -Usage: enriched uranium is formed into metallic tubes called fuel rods, moderators and control rods make sure that the reaction takes place at the desired rate -Storage: after enough uranium has decayed, energy generation is no longer adequate, so the fuel rods must be replaced RISKS AND BENEFITS OF NUCLEAR ENERGY Benefits No air pollution Emissions 4-150 times less than fossil fuel combustion Less chronic health risks and safer work environments Less mining=less damage to landscapes Risks Radioactive waste disposal Waste will emit radiation for thousands of years Waste used to be dumped into the oceans in barrels, now it is held in temporary storage at power plants Yucca Mountain Potential for dangerous accidents Three Mile Island and meltdowns Chernobyl Overall, growth has slowed, new plants aren’t really being built NEW IDEAS Breeder reactors Use U238, which usually goes unused as a waste product 99% of all uranium is U238, so it makes better use of fuel, makes more power, and produces less waste Can be more dangerous because sodium (rather than water) is used as a coolant Are more expensive Create plutonium as a byproduct, which can be used in nuclear weapons Fusion Same process that drives the sun Forces nuclei of lightweight elements together Difficult to do without very high temps (millions of degrees) Requires more energy input than output at this point (EROI of less than 1) BIOENERGY/BIOMASS ENERGY Organic materials derived from living or recently living organisms contains chemical energy from photosynthesis Wood, charcoal, manure Used widely in the developing world Renewable with no net release of carbon dioxide, but it is hard to just the renewability of the resource Biopower can be used in the same way as coal to generate power for electricity, or as a liquid fuel for cars SOURCES OF BIOENERGY Waste products (mostly burned) Bioenergy crops (mostly used for liquid fuels) Co-firing Gasification Scales of production Advantages Fast-growing grasses and trees Combustion strategies Forestry industry, pulp mills, paper mills Agricultural waste (cornstalks, corn husks) Animal wastes Organic waste from landfills Reduction of emissions of some pollutants Resources more evenly spread out Disadvantages Depriving soil of nutrients ETHANOL AND BIODIESEL IN CARS Ethanol Ethanol is produced from fermentation and is added to gas to reduce emissions (any car can run on up to 10% ethanol) 1990 Clean Air Act Flex-fuel vehicles This may not be a sustainable energy choice Overuse of land to grow crops Competition with food production drives up food prices Low EROI 1.5:1 Biodiesel Produced from vegetable oils, used cooking grease, or animal fat Fat is mixed with small amounts of ethanol or methanol in the presences of a catalyst Diesel engines can run on 100% biodiesel, but a 20% mix is more common Lower emissions and competitive prices Biotour Some environmental impacts from growing these crops NEW BIOFUELS AND NEW IDEAS Algae/pond scum Carbon capture potential Cellulosic ethanol No food value, but abundant in all plants Switchgrass (EROI 5:1) Is bioenergy carbon-neutral? In theory yes! But what if we burn forests to plant crops? What is we use fossil fuels to generate the biofuel? HYDROELECTRIC POWER/HYDROPOWER Kinetic energy of moving water turns turbines and generates electricity 2 approaches Storage techniques: Catching water in reservoirs like dams Run-of-River approach: sacrifices reliability of water flow, but minimizes impacts of large dams Accounts for 2.2% of worlds energy supply, 16% of electricity production Dam building began in earnest in the 1930’s and peaked in the 1960’s BENEFITS AND DRAWBACKS Advantages Renewable No carbon emissions (except for those released in the construction of the dam) High EROI of 10:1 Disadvantages Destruction of habitats and flow of natural water cycle Suppresses flood plains Thermal pollution Geologic impacts from weight of water It is unlikely that we will see much more expansion because most of the rivers are already being used THERE’S NO TOMORROW http://www.youtube.com/watch?v=VOMWzjrRiBg 12:07-17:15 Energy Alternatives New Renewable Energy Alternatives: Solar, Wind, Geothermal, Ocean, Hydrogen CHAPTER 21 NEW RENEWABLES Why are they considered new? 1. They are not used on a wide scale (less than 1% today) 2. The technology is still being developed 3. They will likely play a large role in the future All can provide energy for: electricity Heating of air and water Fuel for vehicles Growth is occurring quickly Wind power has grown 50% each year since 1970 Why? Green-collar jobs Policy Feed-in tariff policy SOLAR ENERGY Methods for harnessing solar energy Passive solar: design of buildings, building materials that absorb sun in the winter and keep interior cool in the summer Low south facing windows Window overhangs Thermal mass Vegetation Active solar: devices that focus, move or store solar energy Flat-plate solar collectors SOLAR ENERGY Solar cookers CSP (Concentrated solar power): curved mirrors focus sun on oil in pipes, this heat oil drives turbines to generate electricity Must be in sunny areas, but has great potential PHOTOVOLTAIC CELLS The most direct way to produce electricity is using PV systems Light causes a plate to release electrons which are attracted by electrostatic force to opposing plates Wires connecting plates allows for the flow of a current that can be used as electricity This is what runs your calculator or watch, as well as homes and buildings Thin-film solar cells are lightweight and less bulky, they are also cheaper. Net-Metering versus battery storage BENEFITS AND DRAWBACKS Benefits Inexhaustible as an energy source Energy hitting the planet is more than enough Clean technologies with no moving parts that last for 2030 years Local, decentralized power Reduces deforestation Development of green-collar jobs Drawbacks Location Cost Efficiency WIND ENERGY Wind turbines turn blades which rotate a nacelle to convert kinetic energy of wind into electrical energy Some turbines yaw to respond to wind direction Growth is fast, doubling every 3 years Government has had a series of short-term tax credits Could supply up to 1/5 of our electrical needs by 2030 Offshore sites hold promise Wind is about 20% greater over water and has less turbulence BENEFITS AND DRAWBACKS Benefits No emissions (other than manufacturing equipment) EROI of 11:1 Use less water than conventional power plants Can be used on small and large scales Farmers and ranchers can lease their land for development Drawback Intermittent resource (batteries or hydrogen cells can be used to store energy for later) Wind varies globally Local residents often oppose wind farms NIMBY Threat to birds and bats GEOTHERMAL ENERGY Energy that arises from beneath the Earth’s surface (caused by pressure and radioactive decay of elements) Remember The Geysers in California? Can sometimes be harnessed at the surface from geysers, but more often we have to drill into heated groundwater GEOTHERMAL ENERGY Reduced emissions but may not be sustainable EGS (Enhanced Geothermal Systems) may allow geothermal to be used everywhere Overuse Change in geothermal activity of the planet Engineers pump water into extremely deep wells to create artificially heated groundwater May cause minor earthquakes Heat pumps can be used just about anywhere GSHP’s OCEAN ENERGY SOURCES Kinetic energy from natural motion of the water can generate electrical energy Tidal Energy Wave and Current Energy Dams across the outlets of tidal basins Technology is still being developed Thermal Energy can be used to heat chemicals that would spin turbines and create energy Ocean Thermal Energy Conversion (OTEC) HYDROGEN All energy alternatives can be used to generate electricity, but it is only useful if it can be stored Fuel cells that consist of hydrogen may be an alternative to this problem Electricity generated from an alternative source could be used to produce hydrogen Fuel cells (batteries of hydrogen) could then produce electrical energy for cars, phones, heating, ect. Hydrogen fuel can be produced from water or other matter This is why most car run on gasoline from oil Hydrogen gas doesn’t really exist on Earth Electrolysis of water produces pure hydrogen without emitting any pollution Environmental impact will depend upon Source of hydrogen Source of electricity for electrolysis FUEL CELLS Isolated hydrogen gas can be used to produce electricity within fuel cells Basically the opposite of electrolysis BENEFITS AND DRAWBACKS Benefits We will never run out Energy efficient Silent and non-polluting Drawbacks Lack of infrastructure Leakage of hydrogen can deplete stratospheric ozone THERE’S NO TOMORROW http://www.youtube.com/watch?v=VOMWzjrRiBg 17:15-End Challenges
