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Fossil Fuels

Fossil Fuels

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Fossil Fuels

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  1. Fossil Fuels Non-renewable Energy

  2. Sources of Energy • Sun’s radiation • Biomass – wood • Fossil fuels formed from remains of past organisms • Wind and hydroelectric (sun is ultimate source) • Geothermal • Tidal power • Chemical (bonds)

  3. Sources of Energy • Perpetually renewable: solar, geothermal, wind, tidal • Renewable: timber • Nonrenewable: coal, oil , natural gas • Net energy expresses the difference between returned and invested energy • Fossil fuels: formed from organisms of 100 – 500 MYA

  4. Sources of Energy • Most organisms that die undergo aerobic decay: matter is recycled • Fossil fuels produced by anaerobic decay • Unevenly distributed

  5. coal

  6. Coal • Organic matter compressed under high pressure forming dense, solid carbon structures • Coal use has a long history • Peat: precursor to coal • Classified as lignite, sub-bituminous, bituminous, anthracite; anthracite is most energy-rich

  7. Coal • Impurities in coal include S, Hg, As and other metals • Coal can be mined subsurface or surface

  8. Natural gas

  9. Natural Gas • Much cleaner-burning fuel than coal or oil • Natural Gas is primarily methane • Formed in 2 ways: • Thermogenic gas (deep, from geothermal) aka coalbed methane • Biogenic gas created at shallow depths from anaerobic decay of organic matter (bacteria); new tech: landfill capture

  10. Natural Gas • Only recently widely used (1950’s saw pipeline development) • To access deposits, a drilled opening will allow gas to surface (pressure gradient) • Most fields today require pumping • Offshore drilling produces much of our gas and oil

  11. oil

  12. Oil • Heat and pressure underground form petroleum, aka crude oil (1.5 – 3 km below sfc) • Age of oil began mid-19th century • Petroleum geologists infer the location and size of deposits • Some portion of oil will be impossible to extract using current technology • Technology sets a limit on amount extracted: proven recoverable reserve

  13. Oil • Extraction: drilling • Begins with exploratory drilling • Oil in rocks typically under pressure • Primary extraction – removes about 1/3 of total (initial drilling and pumping) • Secondary extraction –uses solvents, or water/steam to flush the crude; expensive

  14. Oil • We may have depleted half our oil reserves • At current levels of production 40 years worth remain • However as production declines and demand increases, a crisis may occur in the next several years • Industrialization of China and India are increasing the demand

  15. Environmental impacts

  16. Emissions • Air pollution and climate change • CO2 drives global warming • More than CO2 is released – serious consequences for environment and human health

  17. Coal Mining • Surface strip: habitat destruction and soil erosion • Acid drainage occurs when sulfide minerals are exposed to water and O2 • Metal leaching • Inexpensive due to gov’t subsidies

  18. Oil and Gas Extraction • Drilling is minimal, but development process involves more • Fragmentation of habitats • Extensive infrastructure: housing, access roads, pipelines, waste piles • Arctic or semi-arid areas are sensitive

  19. Political and socio-economic impacts

  20. Dependence • Economies tied to fossil fuels are vulnerable • In US – concern over reliance on foreign oil puts pressure to open ANWR to drilling • US has also diversified sources • Oil supply and prices impact economies (crisis of 1973-74) • Residents may not benefit from their fossil fuel reserves (1958, Nigeria, Shell oil extracted $30 billion in oil; poverty is still rampant)

  21. Converting to Renewable Energy • One option – commit to using fossil fuels and develop alternative energies after depletion • Second option – fund development of alternative energy sources now and attempt to reduce reliance on fossil fuels slowly • Third option – end fossil fuel use quickly and hasten renewables

  22. conservation

  23. Conservation • Conservation has followed economic need • Many of the policies developed after the 1973 crisis have been abandoned • Lack of motivation with no immediate threat • US – low taxes on gasoline • Personal choice and increased efficiency are two routes to conservation • Cogeneration – using excess heat to power other devices

  24. Conservation • Both conservation and renewable energy are needed • Reduce energy usage to extend the lifetimes of reserves • Rapid development of renewable resources