Population energy climate change


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  • Population energy climate change

    1. 1. Chapter 2.5 Population, Energy, and Climate Change
    2. 2. What are the Major Air Pollution Problems? <ul><li>Troposphere </li></ul><ul><ul><li>The atmospheric layer closet to earth ’ s surface </li></ul></ul><ul><ul><li>A dynamic system involved in the chemical cycling of the earth vital nutrients </li></ul></ul><ul><li>Stratosphere </li></ul><ul><ul><li>17 to 48 kilometers above the earth ’ s surface </li></ul></ul><ul><ul><li>Ozone layer </li></ul></ul><ul><li>Air pollution </li></ul><ul><li>Primary pollutants </li></ul><ul><li>Secondary pollutants </li></ul><ul><li>Carbon Oxides </li></ul><ul><ul><li>Carbon monoxide (CO) </li></ul></ul><ul><ul><ul><li>A colorless, odorless, highly toxic gas </li></ul></ul></ul><ul><ul><li>Carbon dioxide (CO2) </li></ul></ul><ul><ul><ul><li>Colorless, odorless gas </li></ul></ul></ul><ul><ul><ul><li>93% found in the atmosphere is caused by the natural carbon cycle </li></ul></ul></ul>
    3. 3. What are the Major Air Pollution Problems? <ul><li>Particles </li></ul><ul><ul><li>A variety of solid particles and liquid droplets that remain suspended in the air for long periods. </li></ul></ul><ul><li>Ozone </li></ul><ul><ul><li>O3 is the major component of smog </li></ul></ul><ul><li>Volatile Organic Compounds (VOCs) </li></ul><ul><ul><li>Organic compounds that exist as gases in the atmosphere </li></ul></ul><ul><li>Radioactive Radon (Rn) </li></ul><ul><ul><li>A naturally occurring colorless & odorless radioactive gas found in rocks and soil </li></ul></ul>
    4. 4. What are the Major Air Pollution Problems? <ul><li>Temperature Inversion </li></ul><ul><ul><li>The layer of warm air that lie atop of cooler air near the ground </li></ul></ul><ul><ul><li>Due to cooler air being denser than warmer air above, the result is the air near the surface </li></ul></ul>
    5. 5. How Might the Earth ’s Temperature and Climate Change in the Future? <ul><li>Enhanced Greenhouse Effect </li></ul><ul><ul><li>Global Warming </li></ul></ul><ul><ul><ul><li>Scientists warn that the concern is not just above how much the temperature changes but also how rapidly it occurs. </li></ul></ul></ul>
    6. 6. How can technology help?
    7. 7. Economies are powered by fossil fuels <ul><li>80% of our energy comes from oil, coal, and natural gas </li></ul>
    8. 8. Nations vary in the renewables they use <ul><li>In the U.S., most renewable energy comes from hydropower and biomass. </li></ul>
    9. 9. The new renewables are growing fast <ul><li>They are growing at much faster rates than conventional sources. </li></ul><ul><ul><li>Wind power is the fastest growing. </li></ul></ul><ul><ul><li>However, since these sources began at low levels, it will take time to build them up. </li></ul></ul>
    10. 10. <ul><li>Due to: population and consumption growth, increased energy demand, declining fossil fuel supplies, and the demand for a cleaner environment </li></ul><ul><li>Technological and economic barriers prevent a quick switch to renewables. </li></ul><ul><ul><li>Renewables receive little government help. </li></ul></ul>Rapid growth in renewables will continue The 2007 energy bill passed only after Congress dropped requirements to shift subsidies from non-renewables to renewables and for utilities to increase using renewables.
    11. 11. Biofuels can power automobiles <ul><li>Ethanol : produced as a biofuel by fermenting carbohydrate-rich crops </li></ul><ul><ul><li>Ethanol is widely added to U.S. gasoline to reduce emissions. </li></ul></ul><ul><ul><li>Any vehicle will run well on a 10% ethanol mix. </li></ul></ul>In 2007, the U.S. produced 30 billion L (6.5 million gal) of ethanol in 100 ethanol plants.
    12. 12. Cars can run on ethanol <ul><li>Flexible fuel vehicles : run on 85% ethanol </li></ul><ul><ul><li>But very few gas stations offer this fuel </li></ul></ul><ul><li>Biodiesel : a fuel produced from vegetable oil, used cooking grease or animal fat </li></ul><ul><li>Some people use straight vegetable oil in their diesel engines. </li></ul>
    13. 13. Hydroelectric power <ul><li>Hydroelectric (hydro) power : uses the kinetic energy of moving water to turn turbines and generate electricity </li></ul><ul><li>The storage technique : impoundments harness energy by storing water in reservoirs behind dams </li></ul><ul><ul><li>Water passing through the dam turns turbines. </li></ul></ul><ul><li>The run-of-river approach generates energy without greatly disrupting the flow of river water. </li></ul>
    14. 14. A typical dam
    15. 15. Hydropower is clean and renewable <ul><li>Hydropower has two clear advantages over fossil fuels for producing electricity: </li></ul><ul><ul><li>It is renewable: as long as precipitation fills rivers, we can use water to turn turbines. </li></ul></ul><ul><ul><li>It is clean: no carbon dioxide is emitted. </li></ul></ul><ul><li>Hydropower is efficient. </li></ul><ul><ul><li>It has an EROI of 10:1, as high as any modern-day energy source. </li></ul></ul>
    16. 16. Hydropower has negative impacts <ul><li>Damming rivers destroys riverine habitats. </li></ul><ul><li>Natural flooding cycles are disrupted. </li></ul><ul><li>Sediment deposition </li></ul><ul><li>Thermal pollution of downstream water </li></ul><ul><li>Reducing fish populations and aquatic biodiversity </li></ul>
    17. 17. Hydroelectric power is widely used <ul><li>Nations with large rivers and economic resources have used dams. </li></ul><ul><li>But hydropower is not likely to expand. </li></ul><ul><ul><li>Most of the world ’ s large rivers have already been dammed. </li></ul></ul><ul><ul><li>People have grown aware of the ecological impact of dams. </li></ul></ul>
    18. 18. Solar energy <ul><li>The sun provides energy for almost all biological activity on Earth. </li></ul><ul><ul><li>There is great potential in solar energy, but we are still developing technologies to efficiently use it. </li></ul></ul><ul><li>Passive solar energy : the most common way to harness solar energy </li></ul><ul><ul><li>Buildings are designed to maximize direct absorption of sunlight in winter and keep cool in summer. </li></ul></ul><ul><li>Active solar energy collection : uses technology to focus, move, or store solar energy </li></ul>
    19. 19. Passive solar heating is simple and effective <ul><li>Low south-facing windows maximize heat in the winter. </li></ul><ul><ul><li>Overhangs shade windows in the summer. </li></ul></ul><ul><li>Thermal mass : construction materials that absorb, store, and release heat </li></ul><ul><li>By heating buildings in winter and cooling them in summer, passive solar methods conserve energy and reduce costs. </li></ul>
    20. 20. Active solar energy collection <ul><li>Flat plate solar collectors (solar panels) : one active method for harnessing solar energy </li></ul><ul><ul><li>Installed on rooftops </li></ul></ul><ul><ul><li>Dark-colored, heat-absorbing metal plates </li></ul></ul><ul><ul><ul><li>Water, air, or antifreeze pass through the collectors, transferring heat throughout the building. </li></ul></ul></ul><ul><ul><ul><li>Heated water is stored and used later. </li></ul></ul></ul><ul><ul><ul><li>Effective for heating water for homes </li></ul></ul></ul>
    21. 21. Focusing solar rays magnifies energy <ul><li>Focusing solar energy on a single point intensifies its strength. </li></ul><ul><li>Solar cookers : simple, portable ovens that use reflectors to focus sunlight onto food </li></ul><ul><li>Power tower : mirrors concentrate sunlight onto receivers to create electricity </li></ul>In southern California, a power tower produces power for 10,000 households.
    22. 22. Solar power is little used but fast growing <ul><li>Solar energy was pushed to the sidelines by fossil fuels. </li></ul><ul><ul><li>Because of a lack of investment, solar energy contributes only a miniscule amount of energy. </li></ul></ul><ul><ul><li>But solar energy use has grown 25%/year since 1971. </li></ul></ul><ul><li>Solar energy is attractive in developing nations. </li></ul><ul><ul><li>Where hundreds of millions don ’ t have electricity </li></ul></ul><ul><li>The U.S. may recover its leadership, given a 2005 federal tax credit and some state initiatives. </li></ul><ul><li>Solar energy use should increase as prices fall, technologies improve, and governments enact economic incentives. </li></ul>
    23. 23. Solar power offers many benefits <ul><li>The sun will burn for 4 – 5 billion more years. </li></ul><ul><li>Solar technologies use no fuels, are quiet, safe, contain no moving parts, and require little maintenance. </li></ul><ul><li>They allow local, decentralized control over power. </li></ul><ul><li>Developing nations can use solar cookers and photovoltaics. </li></ul><ul><li>Net metering : PV owners can sell excess electricity to their local power utility </li></ul><ul><li>New jobs are being created. </li></ul><ul><li>Solar power does not emit greenhouse gases and air pollution. </li></ul><ul><ul><li>Manufacturing units currently require fossil fuels. </li></ul></ul>
    24. 24. Location is a drawback <ul><li>Not all regions are sunny enough to provide enough power, with current technology. </li></ul><ul><ul><li>Daily and seasonal variation also poses problems. </li></ul></ul><ul><li>Up-front costs are high and solar power remains the most expensive way to produce electricity. </li></ul><ul><ul><li>Future technologies will be much more efficient and have lower costs. </li></ul></ul>
    25. 25. Modern wind turbines convert kinetic energy <ul><li>Wind turbines : devices that turn wind energy into electricity </li></ul><ul><ul><li>Wind blowing into a turbine turns the blades of the rotor, which rotate machinery inside a compartment ( nacelle ) on top of a tall tower. </li></ul></ul><ul><li>Towers are 40 – 100 m (131 – 328 ft) tall. </li></ul><ul><ul><li>Higher is better to minimize turbulence and maximize wind speed. </li></ul></ul>
    26. 26. Wind is the fastest-growing energy sector <ul><li>Wind farms : turbines erected in groups of up to hundreds of turbines </li></ul><ul><li>Wind power grew 26% per year globally between 2000 and 2005. </li></ul><ul><ul><li>Five nations account for 80% of the world ’ s wind power. </li></ul></ul><ul><li>California and Texas produce the most wind power in the U.S. </li></ul><ul><ul><li>Wind power could be expanded to meet 30% of the U.S. electrical needs by 2030. </li></ul></ul>
    27. 27. Wind power has many benefits <ul><li>Wind produces no emissions once installed. </li></ul><ul><li>It prevents the release of CO 2, , SO 2 , NO x , mercury. </li></ul><ul><li>It is more efficient than conventional power sources. </li></ul><ul><li>Turbines also use less water than conventional power plants. </li></ul><ul><li>It can be used on many scales, from one turbine to hundreds. </li></ul><ul><li>Farmers and ranchers can lease their land. </li></ul><ul><ul><li>Produces extra revenue </li></ul></ul><ul><ul><li>Landowners can still use their land for other uses. </li></ul></ul>
    28. 28. Wind power has some downsides <ul><li>We have no control over when wind blows. </li></ul><ul><ul><li>This poses little problem if wind is one of several sources of electricity. </li></ul></ul><ul><li>Good wind sources are not always near population centers that need energy. </li></ul><ul><li>Residents often oppose wind farms near population centers. </li></ul><ul><li>Wind turbines also kill birds and bats when they fly into rotating blades. </li></ul>
    29. 29. U.S. wind-generating capacity <ul><li>Mountainous regions have the most wind capacity. </li></ul>
    30. 30. Conclusion <ul><li>More people are becoming convinced that we need to shift to renewable energy sources. </li></ul><ul><ul><li>Biomass and hydropower already play important roles. </li></ul></ul><ul><ul><li>Renewable sources include solar, wind, geothermal, and ocean energies. </li></ul></ul><ul><ul><li>Hydrogen fuel may produce electricity. </li></ul></ul><ul><li>Most renewable sources have been hampered by inadequate funding for research and by artificially cheap fossil fuels. </li></ul><ul><ul><li>But there is hope that we can shift to renewables with minimal disruption. </li></ul></ul>
    31. 31. What do you know?
    32. 32. QUESTION: Review <ul><li>We can harness power from wind by using devices called: </li></ul><ul><ul><li>Wind turbines </li></ul></ul><ul><ul><li>Wind parks </li></ul></ul><ul><ul><li>Wind farms </li></ul></ul><ul><ul><li>Solar cells </li></ul></ul><ul><ul><li>Nacelles      </li></ul></ul>
    33. 33. QUESTION: Interpreting Graphs and Data <ul><li>Maine, Florida </li></ul><ul><li>Texas, Kentucky </li></ul><ul><li>Arizona, Idaho </li></ul><ul><li>North Dakota, Ohio </li></ul><ul><li>Louisiana, Oklahoma </li></ul>_____ is the best state for producing solar energy, while _____ is best for wind energy. Solar Wind