Energy & Electricity
History of Electricity/Grid Electricity “system” created in US 1881 Purpose was electricity for lights 1881 cost: $0.24/kWh! (now ~$0.10) Early 1900’s: inter-city transmission lines 1930s-1950s: rural electrification, federally-run electric generating plants (hydro) 1950s- now: nuclear power, environ. controls, fuel costs, Three Mile Island
“Making” electricity For wind & hydro, skip step 1 For PV solar skip 1 and 2 coal, natural gas, nuclear fission, wood, solar energy steam, water, air Boiler (1) (2) Turbine Generator (3)
Electricity delivery
Making electricity not efficient infosite/elec&env7/roleofenergy7_3/effi ciencyinpowerstat/energylosses/energylo sses.htm Doesn’t include losses along transmission lines, another 5-10%
Coal-fired electricity Pros Cheap Abundant New technologies to help with emissions Cons Resource finite Emissions Carbon SO x NO x Particulate Matter Mercury Mining Health & environment Transportation
Natural gas Pros Cleaner than coal Dispatchable “Combined cycle” makes plants more efficient Cons Costs variability & uncertainty Emissions Supply questionable
Nuclear power Pros No CO 2 emissions Cheap? Abundant fuel 3% of all topsoil is U235 Cons Cheap? High impact/low occurrence risk No closure to life cycle Waste, Yucca mountain Security
Hydroelectric power Pros Emissions very low Opportunity for storage Cheap Flood control Water supply Cons Devastating to wildlife and surrounding area Owner has control of the river downstream Dependent on weather
“Renewables” Solar, Wind, Thermal, Tidal Pros Low emissions Resource requirements low Energy independence Cons Costs Intermittency Location Not necessarily renewable
What’s your consumption mix? Consumption mix: the fraction of each type of generation a specific region, state, business, or individual consumes Can then figure out what the environmental impact of that entity’s consumption is Split up into 4 groups
What information do I need? Type of nearby generators Power plants, dams, windmills, solar arrays Proportion – amount of total generation made up by each type 40% type A, 30% type B, 30% type C
Regions: NW, NE, SE, SW Generation Types: Coal Natural Gas Petroleum Nuclear Hydroelectric Solar Wind Geothermal Biomass Other
Guesses for your region?
Solar Intensity
Wind Intensity
Natural Gas Pipelines
Precipitation
Coal Deposits
Northeast US
Southeast US
Southwest US
Northwest US
US Generation Mix
Guesses for Pennsylvania?
Pennsylvania
California
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? Include interstate trading These numbers have a significant impact, so new generation mixes, which include trading, are created for each state
CA: Where Does the Electricity Come From? Net Imports (TWh)
California imports from other states
The California Consumption Mix
Electricity wrap-up Most power generated by burning fossil fuels The problem is not that we will run out! Burning these things likely produces unwelcome effects on a planet-wide level % of electrification good proxy of level of development and quality of life 25% of the world is not electrified (~1.6 billion people)
Other social costs? Air Standard pollutants Hg, Se, Cd Water Acid mine drainage Water system disruption Fishing Waste Spent batteries and cells Spent nuclear fuel Safety issues Rail Pipelines Turbines Aesthetics Wind turbines Steam Transmission lines Smog Externality: “Costs that society must pay which are not borne by the producers”
In green design, we try to find ways to generate the positives associated with electricity without the negatives Advanced nuclear Carbon sequestration Combined heat & power Large scale renewables Distributed generation 3 things you can do to help: 1. Conservation every unit of output you save means 3 units of input saved 2. Conservation pay attention to things around you which consume power 3. Conservation make power consumption a factor in deciding which things you purchase