1 Where Does Electricity Come From? 2 Overview of Electricity 3 Power Generation 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 5 Coal Fired Power Plant 6ov.au/electricity/infosit e/elec&env7/roleofen ergy7_3/efficiencyinp owerstat/energylosse s/energylosses.htm 7 8 9 10 11 12 Advanced Coal Technologies Increases Efficiency to up to 65% - increased cost, materials etc. 13 Life Cycle of Coal-Fired Electricity 14 Nuclear Pros No CO 2 emissions Cheap? Cons Cheap? High impact/low occurrence risk No closure to life cycle 15 Natural Gas Pros Cleaner than coal Dispatchable Cons Costs variability & uncertainty Emissions Supply questionable 16 Hydro Pros Emissions very low Opportunity for storage Cheap Cons Devastating to wildlife and surrounding area Dependent on weather 17 Renewables Solar, Wind, Thermal, Tidal Pros Low emissions Resource requirements low Energy independence Cons Costs Intermittency Location Not necessarily renewable 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 1900s - intercity transmission lines 1930s-1950s: rural electrification, federally- run electric generating plants (hydro) 1950s- now: nuclear power, environ. controls, fuel costs, Three Mile Island 19 Where does my electricity come from? Creating generation mixes 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 21 Guesses for Pennsylvania? 22 Solar Intensity 23 Wind Intensity 24 Precipitation 25 Coal Deposits 26 US Generation Mix Other: Solar, Wind, Biomass, Geothermal, etc 27 Guesses for Pennsylvania? 28 Pennsylvania Generation Mix 29 Is that the whole story? What if power plants near me dont generate enough electricity to meet my needs? Pennsylvania does, but what about California and New York? 30 Include Interstate Trading Lots of electricity transfer in the United States, especially following deregulation in 1996 Currently, interstate electricity transfer ignored, but its 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 31 Where Does the Electricity Come From? Net Imports (TWh) Source: EPA eGrid California Distances 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 34 Completed Optimization Showing Electricity Transactions (Shipments) in TWh 35 California Transfers 36 The California Consumption Mix NOTE: Exporting states retain their original generation mixes 37 Overview Policy Problem: Should energy be transported from the source to the demand as fuel or electricity? Economics Environmental Impacts Social Impacts 38 Overview of Problem 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 40 US Coal Supply and Population A ton of coal is shipped by rail an average distance of 800 miles 41 Life Cycle of Coal-Fired Electricity 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%) 43 Base Case Economic Results 44 Air Emissions (30 years) 45 Comparative Annual Energy Consumption 46 Some Alternatives Coal to Methane or Hydrogen Coal Slurry Pipeline AC Transmission High Temperature Superconductors Barge and Rail