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1、,Energy Resources,Chapter 10,Energy Resources,Supplementing free solar energy99% of heat comes from the sunWithout the sun, the earth would be 240 0C (-400 0F)We supplement the other 1% with primarily non-renewable energy sources,Energy Resources,Renewable (16%)SolarWindFalling, flowing waterBiomass
2、,Non-renewable (84%)OilNatural gasCoalNuclear power,Energy sources and uses,Energy uses in developed countries industrialdomestictransportationNote: Electricity is not an energy source, converted from another source (coal, hydro, nuclear, etc.). 1st Law of Thermodynamics - You cant get more energy o
3、ut of something than you put in2ond Law In any conversion of heat energy to useful work, some energy is always degraded to a lower quality energy,Evaluating Energy Resources,RenewableFuture availabilityNet energy yieldIt takes energy to get energyHabitat degradationCost (initial and ongoing)Communit
4、y disruptionPolitical or international issuesSuitability in different locationsPolluting (air, water, noise, visual),Each type of power project needs to be evaluated for the benefits and costs,The environmental costs of hydroelectricity are much different than windpower, for example,Important Nonren
5、ewable Energy Sources,North American Energy Resources,Average American uses in one day what a personin the poorest countries use in one year,US has only2.4% of worldsoil reserves,OIL and NATURAL GAS,Accumulations of dead marine organisms on the ocean floor were covered by sediments.Muddy rock gradua
6、lly formed rock (shale) containing dispersed oil.Sandstone formed on top of shale, thus oil pools began to form.Natural gas often forms on top of oil.Primary component of natural gas is methane,Oil,Petroleum (crude oil)Costs:RecoveryRefining TransportingEnvironmentalHighest risks are in transportati
7、onRefining yields many productsAsphaltHeating oilDieselPetrochemicalsGasoline,Based on boiling points,Conventional Oil,AdvantagesRelatively low cost High net energy yield Efficient distribution system,DisadvantagesRunning out 42-93 years Low prices encourage waste Air pollution and greenhouse gases
8、Water pollution,Arctic National Wildlife Refuge Controversy: Trade-offs,Would create jobs Oil resources are uncertainUS supply 7-24 months Uncertain environmental impacts,Oil Shale and Tar Sands,Tar Sand:Mixture of clay, sandwater and bitumen -a thick and stickyheavy oil.Extracted by largeelectric s
9、hovels,mixed with hot water and steam to extractthe bitumen.Bitumen heated toconvert to syntheticcrude oil.,Oil Shale:Oily rocks thatcontain a solidmix of hydro-carbons.Global supplies 240 times conventional oilsupplies.,Natural Gas,50-90% methaneCleanest of fossil fuelsApproximate 200 year supplyAd
10、vantages and disadvantages,Coal What is it?,Solid fossil fuel formed in several stages Land plants that lived 300-400 million years agoSubjected to intense heat and pressure over many millions of yearsMostly carbon, small amounts of sulfur,Coal Formation and Types,Coal what do we use it for?,Stages
11、of coal formation300 million year old forestspeat lignite bituminous anthracitePrimarily strip-minedUsed mostly for generating electricityUsed to generate 62% of the worlds electricityUsed to generate 52% of the U.S. electricityEnough coal for about 200-1000 yearsU.S. has 25% of worlds reservesHigh
12、environmental impactCoal gasification and liquefaction,Coal: Trade-offs,Worlds most abundant fossil fuelMining and burning coal has a severe environmental impactAccounts for over 1/3 of the worlds CO2 emissions,Nuclear Energy What is it?,A nuclear change in which nuclei of certain isotopes with larg
13、e mass numbers are split apart into lighter nuclei when struck by neutrons.Nuclei center of an atom, making up0 most of the atoms massIsotopes two or more forms of a chemical element that have the same number of protons but different mass numbers because they have different numbers of neutrons in th
14、eir nuclei.Neutron elementary particle in all atoms.Radioactivity Unstable nuclei of atoms shoot out “chunks” of mass and energy.,Nuclear Energy,Fission reactorsUranium-235FissionResulting heat used to produce steam that spins turbines to generate electricityProduces radioactive fission fragments,Li
15、ght water generator used inall U.S. and 85% world wide.,Great danger of losing coolant!,Locations of U.S. Nuclear Power Plants,The Nuclear Fuel Cycle,Produces highly radioactive materials that must be stored safely for 10,000-240,000 years.,Conventional Nuclear Power: Trade-offs,No new plants in U.S
16、.since 1978.All 120 plants orderedin 1973 have been cancelled.Cost over-runsHigh operating costsThree Mile IslandChernobyl,Three Mile Island - Pennsylvania,March 28, 1979 - Partial Core Melt-Down.No Deaths.Very Little Radiation Vented.Public Relations Disaster.,Chernobyl Ukraine (Former USSR),April
17、26, 1986One of four reactors explodes.31 immediate deaths.116,000 people evacuated.24,000 evacuees received high doses of radiation.Thyroid cancer in children.Damaged reactor entombed in concrete, other reactors returned to service within months.Eventually, remaining reactors out of service.,Dealing
18、 with Nuclear Waste,High- and low-level wastesTerrorist threats storage casks hold 5-10 X more ling-lived radioactivity than the nuclear power plantDisposal proposalsUnderground burialDisposal in space (illegal under international law)Burial in ice sheets (“ “)Dumping into subduction zones (“ “)Buri
19、al in ocean mud (“ “)Conversion into harmless materials (no way to do this with current technology),Yucca Mountain,In 1982, Congress called for a high-level radioactive disposal site to be selected by March 1987, and to be completed by 1998.Final Site Selection Occurred in 1989.Yucca Mountain, Nevad
20、aNot to be completed before 2015.Wastes stored and guarded in one placePossible long-term groundwater contaminationSecurity and safety concerns during waste transport to the siteCritics contend it is safer to store wastes at existing nuclear power plants.,Permanent Underground Disposal of Nuclear Wa
21、stes,Storage Containers,Fuel rod,Primary canister,Overpackcontainersealed,Underground,Buried and capped,Ground Level,Unloaded from train,Lowered down shaft,Personnel elevator,Air shaft,Nuclear waste shaft,Low - Level Waste (materials other than the radioactive isotopes),Includes cooling water from n
22、uclear reactors, material from decommissioned reactors, protective clothing, and like materials.Prior to 1970, US alone placed 50,000 barrels of low-level radioactive waste on the ocean floor.Moratorium in 1970, Ban in 1983.,Energy Efficiency and Renewable Energy,84% of energy is wasted in the Unite
23、d States41% degradation (2ond law of Thermodynamics)43% unnecessaryFuel wasting vehiclesFurnacesPoorly insulated buildingsU.S. unnecessarily wastes 2/3 of the energy that the rest of the worlds population consumes!,Energy Efficiency and Renewable Energy,Four primary energy wasters:Incandescent light
24、 bulb 95%Nuclear Power 86% Cars 75-80%Coal 66%,Energy Efficiencies do more with less!,Ways to Improve Energy Efficiency,Cogeneration combines heat and powerTwo forms of energy (ex. steam and electricity) are provided from the same fuel source. Used in Western Europe, U.S. produces 9% of electricity
25、using cogeneration plants)Efficient electric motorsHigh-efficiency lightingIncreasing fuel economyAlternative vehiclesInsulation Plug leaks,Hybrid and Fuel Cell Cars,Hybrid cars still use traditional fossil fuelsEnergy otherwise wasted charges battery which assists acceleration and hill climbingMore
26、 efficient than internal combustion engine alone, but still uses non-renewable resourcesFuel cell cars not yet available Hydrogen gas is fuelVery efficientLow pollutionMajor infrastructure change needed for fueling stations,Renewable energy sources,SolarFlowing waterWindBiomassGeothermalHydrogen,Usi
27、ng Solar Energy to Provide Heat,Passive solar heating,Active solar heating,Using Solar Energy to Provide High-Temperature Heat and Electricity,Solar thermal systemsPhotovoltaic (PV) cells,Producing Electricity from Moving Water,Large-scale hydropowerSmall-scale hydropowerTidal power plantWave power
28、plant,Producing Electricity from Wind,Producing Energy from Biomass,Biomass and biofuelsBiomass plantationsCrop residuesAnimal manureBiogas Ethanol Methanol,Geothermal Energy,Geothermal heat pumpsGeothermal exchangeDry and wet steamHot waterMolten rock (magma)Hot dry-rock zones,The Hydrogen Revoluti
29、on,Environmentally friendlyExtracting hydrogen efficientlyStoring hydrogenFuel cells,Hydrogen Trade-offs,Entering the Age of Decentralized Micropower,Decentralized power systemsMicropower systems,Solutions: A Sustainable Energy Strategy,What Can You Do?,Energy Use and Waste,Drive a car that gets at
30、least 15 kilometers per liter (35 miles per gallon) and join a carpool.Use mass transit, walking, and bicycling.Super-insulate your house and plug all air leaks.Turn off lights, TV sets, computers, and other electronic equipment when they are not in use.Wash laundry in warm or cold water.Use passive
31、 solar heating.For cooling, open windows and use ceiling fans or whole-house attic or window fans.Turn thermostats down in winter and up in summer.Buy the most energy-efficient homes, lights, cars, and appliances available.Turn down the thermostat on water heaters to 43-49C (110-120F) and insulate hot water heaters and pipes.,
