chapter 12 energy from fossil fuels environmental science
TRANSCRIPT
Chapter 12 Energy from Fossil Fuels
Environmental Science
In The Past
Disadvantages Electricity from Coal Burning
• Pollution from primary energy source of burning coal, especially CO2 global warming
• Coal contains sulfur, mercury and sometimes radioactive contaminants that when burned enter our atmosphere to make it to water ways, etc
• Sulfur oxide compounds create acid rain and acidic soil & waterways making it hard on biota•Environmental effects of the mining process also like habitat alterations, mineral leaching, erosion, formation of sinkholes, etc•Only 35%efficiency of 2ºenergy source
OPEC Members
• AFRICA: Algeria, Angola, Nigeria, Libya• S. AMERICA: Ecuador, Venezuela• MIDDLE EAST: Saudi Arabia, Iran, Iraq, Kuwait, Qatar,
United Arab Emirates
US Oil Production and Consumption•OPEC: Organization of Petroleum Exporting Countries•Arab Oil Embargo: OPEC Arab members blocked exports of oil to US from Oct 1973 to March 1974 for the US support of Israel in Yom Kippur War•Strategic Reserve
Economics of Energy Use
Supply side economic fixes to high energy pricesIncrease domestic production
Exploratory drillingAlaska Pipeline
Demand side fixes to high energy prices: Decrease consumption
CAFÉ Standards, Fuel efficiency (Corporate Average Fuel Economy)Conservation goals and energy efficiency55 mph speed limitsAlternative energies technological development, tax incentives and government investments
Consumption, Domestic Production, and imports of Petroleum
Hubbart Predictions • U.S. Oil production would peak (1970s)• Dependence on OPEC oil will increase• Oil production will follow a bell-shaped curve
Issues of Foreign Dependence?
• Trade imbalances• Military actions• Pollution of oceans• Coastal oil spills• Variations in cost of purchases• Threat of supply disruptions• Limitations of nonrenewable resource
What does a barrel really cost?
• $14 in initial costs
• + $80 for military support services
• = $94 per barrel of oil
Other Fossil Fuels
• Natural Gas– Cost subject to market fluctuation– Currently have a 50 year supply– Pipeline dangerous b/c kept at high pressure– Used for heating/furnace– Can run a modified car, liquified gas– Made into synthetic oil
Other Fossil Fuels
• Coal– 56% of electricity– 250 year supply– Produce more coal than use– Mining issues?– Lots of waste (20,000 tons CO2, 800 tons SO2
– Synfuels! (by-products are an issue)
Other Fossil Fuels
• Oil Shales and Oil Sands– Once heated, vapors condensed into something
similar to crude oil– Use/modification extremely impractical at the
moment
Issues of Using Fossil Fuels
Cogeneration
ANWR
• Read Ethics section on page 305-306• I’ve assigned you a side
– Black: Pro drilling– Red: Anti-drilling
• Research and have a debate/discussion on Monday
Mining Techniques• Mining is the extraction of valuable minerals or other geological
materials from the earth, usually from an ore (rock) body, mineral vein or coal seam
• Process: mining usually involves first removing overlying soil and rock (the overburden) and putting this into valleyfills or tailing piles
• Surface mining is more common (98% of metallic ores) includes: Open pit mining (big deep holes), Strip mining (removing surface layer), Mountain Top Removal (often used with coal deposits)
• Subsurface Mining including: drift mining (horizontal access tunnels), shaft mining (vertical) and slope mining
• In-situ leaching (uses acids to dissolve the minerals, usually U)• Tailings are the excess waste rock, minerals and contaminants
Mining Techniques
• Copper Ore is typically the mineral chalcopyrite (CuFeS2) or sometimes found in malachite mineral CuCO3•Cu(OH)2
• Average grade of 0.6% for Cu ore• Extractive metallurgy Process: pulverize
the ore, solubolize it with acids (leaching) or with smelting (heating and electrolysis), then isolate the Cu through redox chemical reactions
Coal Mining Reclamation• Surface mining is common
proactive in WyomingReclamation of Wyoming prairies and rolling hills is often very successful
Not as complicated an ecosystem as those with mountains, forests and river beds
Mountain Top Removal mining, often used in Appalacian Mountains in the East, has been less suscessful with reclamation•724 miles of Appalacian streams buried by valley fills from 1985 to 2001, loss of biodiversity•Nearby streams higher levels of acid content (sulfur run-off from coal) and thus more dissolved minerals and heavy metals•Blasting releases dust and flyrock with high sulfur content causing corrosion of structures•Sometimes no reforestation, possible erosion issues
Surface Mining Control and Reclamation Act“smackra” SMCRA 1977, under President Carter, is primary federal law
regulating env. impact of coal miningIt requires Coal Companies to:• set up bonds controlled by the government to pay for reclamation cost
estimates• Restore/reclaim land by recontouring/regrading land to original topography,
adding topsoil and/or nutrients, replanting native vegetation (fast growing secondary successional species), monitoring for either 5 or 10 years after
• Possible remediations (or fines) for excessive sulfur (H2SO4 acid) tailings include: neutralize with alkaline/base substances like limestone (CaCO3), NaOH, NaHCO3, and ammonia NH3, cover tailings to reduce precipitation contact; bioremediation with sulfate-reducing bacteria; tailings ponds/retention basins to prevent airborne movement
In-situ mining for Uranium• Injected solutions to dissolve
minerals, then extraction and recrystalization