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Published byMelvyn Hoover Modified over 9 years ago
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1 Where Does Electricity Come From?
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2 Overview of Electricity
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3 Power Generation
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4 Coal Pros Cheap Abundant New technologies to help with emissions Cons Environmental emissions (SO 2, NO x, PM, Mercury, etc) Mining impacts Health & environment
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5 Coal Fired Power Plant
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6 http://www.energy.qld.g ov.au/electricity/infosit e/elec&env7/roleofen ergy7_3/efficiencyinp owerstat/energylosse s/energylosses.htm
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12 Advanced Coal Technologies Increases Efficiency to up to 65% - increased cost, materials etc.
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13 Life Cycle of Coal-Fired Electricity
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14 Nuclear Pros No CO 2 emissions Cheap? Cons Cheap? High impact/low occurrence risk No closure to life cycle
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15 Natural Gas Pros Cleaner than coal Dispatchable Cons Costs variability & uncertainty Emissions Supply questionable
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16 Hydro Pros Emissions very low Opportunity for storage Cheap Cons Devastating to wildlife and surrounding area Dependent on weather
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17 “Renewables” Solar, Wind, Thermal, Tidal Pros Low emissions Resource requirements low Energy independence Cons Costs Intermittency Location Not necessarily renewable
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18 History of Electricity/Grid Electricity ‘system’ created in US 1881 Purpose was electricity for lights 1881 cost: 24 cents/kWh! (now ~10 cents) Early 1900’s - intercity transmission lines 1930s-1950s: rural electrification, federally- run electric generating plants (hydro) 1950s- now: nuclear power, environ. controls, fuel costs, Three Mile Island
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19 Where does my electricity come from? Creating generation mixes
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20 What information do I need? 1. Type of nearby generators (Power plants, dams, windmills, solar arrays) 2. Proportion – amount of total generation made up by each type (40% type A, 30% type B, 30% type C) Generally state lines used as borders
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21 Guesses for Pennsylvania?
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22 Solar Intensity
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23 Wind Intensity
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24 Precipitation
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25 Coal Deposits
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26 US Generation Mix Other: Solar, Wind, Biomass, Geothermal, etc
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27 Guesses for Pennsylvania?
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28 Pennsylvania Generation Mix
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29 Is that the whole story? What if power plants near me don’t generate enough electricity to meet my needs? Pennsylvania does, but what about California and New York?
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30 Include Interstate Trading Lots of electricity transfer in the United States, especially following deregulation in 1996 Currently, interstate electricity transfer ignored, but it’s a big part of the market 25% of California power is imported West Virginia exports 70% of theirs These numbers have a significant impact, so new generation mixes, which include trading, are created for each state
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31 Where Does the Electricity Come From? -69.1 -11.9 -3.3 -3.1 1.1 4.8 10.2 11.8 12.3 20.1 29.1 2000 Net Imports (TWh) Source: EPA eGrid
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32 0 595 246 802 718 246 486 875 805 447 719 1229 1160 1133 1161 1258 1252 California Distances
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33 Import-Export Model: Linear Optimization Classic transportation/distribution problem Using two matrices of data (27 x 27) 1. Distances from exporters to importers 2. Shipments of power from exporters to importers Minimize the sum-product of these matrices The “cost” of moving electricity from exporters to importers Subject to the following constraint All electricity in system needs to be “used” – each row/column in shipments matrix must sum to net surplus/deficit calculated from EPA data By changing the amounts in the shipments matrix
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34 Completed Optimization Showing Electricity Transactions (Shipments) in TWh
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35 California Transfers 4.8 10.2 9.2 20.1 24.8 2.1
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36 The California Consumption Mix NOTE: Exporting states retain their original generation mixes
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37 Overview Policy Problem: Should energy be transported from the source to the demand as fuel or electricity? Economics Environmental Impacts Social Impacts
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38 Overview of Problem
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39 Group Activity Individually, take 2 minutes to decide which you think is best and why Consider the life cycle stages Consider economic, environmental and social impacts Consider what infrastructure exists and what might need to be built new Be ready to explain which option you think makes the most sense and why Compare thoughts with 2-3 of your neighbors. Share comments with the class
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40 US Coal Supply and Population A ton of coal is shipped by rail an average distance of 800 miles
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41 Life Cycle of Coal-Fired Electricity
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42 Base Case Assumptions Power Plants identical (SUPC – 40% efficiency, 75% capacity factor) Therefore base production ignored for comparison 1000 MW (plus compensation for 7% transmission line losses) Approximately 1000 miles No siting difficulties or grade crossing upgrades Capital Rail – minimal new track capacity, new trains Transmission – new HVDC lines, substations Amortized over life of investment (cost of capital 8%)
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43 Base Case Economic Results
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44 Air Emissions (30 years)
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45 Comparative Annual Energy Consumption
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46 Some Alternatives Coal to Methane or Hydrogen Coal Slurry Pipeline AC Transmission High Temperature Superconductors Barge and Rail
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