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cassidy-cohen

Global Warming - PowerPoint PPT Presentation

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Global Warming
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  1. Global Warming Project lead the way Ohio Hocking College Fuel Cell Training Seminar July 23 – 27, 2007

  2. Atmospheric Energy Factors • Earth is in a steady state, the energy stored in the atmosphere and ocean does not change rapidly over time. • Energy equal to the absorbed solar radiation must be radiated back to space. • Earth radiates energy into space in the infrared wavelengths with an intensity that increases with increasing temperature. • Therefore, one can think of the Earth's temperature as being determined by the infrared flux needed to balance the absorbed solar flux.

  3. Layers in the atmosphere • Troposphere: from 0 – 11 miles high. Contains most of the air. A thin layer where our weather occurs. Ozone here is a pollutant. • Stratosphere: from 11 – 30 miles high. Not as dense as the troposphere, and contains much more ozone and less water vapor. NASA shuttle photo of a sunset over South America

  4. Greenhouse Effect • The radiation from the sun is a different wavelength from the radiation that is emitted from the earth’s surface. It easily passes through the earth’s atmosphere • The radiation emitted from the surface is a different wavelength and ‘Greenhouse gases’ absorb some it and thus, reducing the flow of the sun’s heat back into space. • Diagram from www.eecs.umich.edu/mathscience/funexperiments/agesubject/lessons/images/diagrampage.html

  5. Global Warming Definitions • The amplified warming of the earth’s troposphere as a result of increases in the concentrations of one or more greenhouse gases. • Global warming is the gradual increase in global temperatures caused by the emission of gases that trap the sun's heat in the Earth's atmosphere. • An overall increase in world temperatures which may be caused by additional heat being trapped by greenhouse gases.

  6. Greenhouse Gases • Greenhouse gases (GHG) are gaseous components of the atmosphere that contribute to the greenhouse effect. • The major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect on Earth carbon dioxide, which causes between 9-26%; methane which causes 4 to 9% and ozone, which causes between 3-7% • Minor greenhouse gases include, but are not limited to: methane, nitrous oxide, sulfur hexafluoride, and chlorofluorocarbons • Nitrogen and oxygen are not greenhouse gases, because they do not absorb infrared radiation

  7. Evidence for global warming from Intergovernmental Panel on Climate Change (2001 report): The 20th century was the hottest century in the past 1,000 years. The average global temperature near the earth’s surface has risen 0.6 degrees C, mostly since 1980.The 16 warmest years on record have occurred since 1980,and the 10 warmest years since 1990. During the last century the world’s average sea level rose 4-8 inches because of runoff of water from melting land-based ice, and also because ocean water expands when its temperature increases. Global emissions of CO2 now amount to about 24 billion tons per year, released from fossil fuel combustion

  8. Since 1979 the size of the summer polar ice cap has shrunk more than 20%. Its thickness has decreased more than 40%.

  9. Determining CO2 Levels • Glaciers provide important information about the composition of the atmosphere through time. • Gas bubbles (little pieces of ancient atmosphere) are trapped in glaciers. • Bubbles can be analyzed for percentages of gases. • Scientists have found that changes in tropospheric carbon dioxide correlate well with estimated variations in the average global temperature.

  10. CO2 Levels from Ice Cores • After being steady at 280 ppm for 600 years carbon dioxide levels in the atmosphere have increased to 340 ppm in the last 250 years. • Data source: elmhcx9.elmhurst.edu/.../issues/issue197.html

  11. Consequences of Global Warming • More frequent heat waves, droughts, fires, costal flooding and storms. • Some infectious diseases, such as malaria, will spread to new regions • High concentrations of ground-level ozone will exacerbate heart and respiratory ailments • By 2080 rising sea levels will flood the homes and property of millions of people

  12. Response to Global Warming • Adaptation - Living organisms will learning how to survive and prosper in a warmer world. • Mitigation – Limit the extent of future warming by reducing the net release of greenhouse gases to the atmosphere. • Above responses from Aug 2007 article in Scientific American

  13. Kyoto Protocol • The Kyoto Protocolto the United Nations Framework Convention on Climate Change is an international treaty on climate change. • Objective - the assigning mandatory emission limitations for the reduction of greenhouse gas emissions to the signatory nations • Countries which ratify this protocol commit to reduce their emissions of carbon dioxide and five other greenhouse gases, or engage in emissions trading if they maintain or of these gases.

  14. Hydrocarbon Fuels • Throughout the history of humankind, many different fuels have been burned to provide energy: • Wood (used for more than a million years) • Peat • Coal (a combustible organic rock composed primarily of carbon, hydrogen, and oxygen. ) • Oil • Natural gas

  15. All of these fuels contain hydrogen and carbon. During combustion, the carbon and hydrogen atoms react with atmospheric oxygen to produce CO2 and H2O. (You can not see the CO2)

  16. Burning Hydrocarbons • If perfect combustion is obtained the products of burning a hydrocarbon are CO2 + H2O Gasoline + Oxygen  CO2 + H2O 2C8H18 + 25O2 16CO2 + 18H2O • Methane + Oxygen  CO2 + H2O 2CH4 + 4O2 2CO2 + 4H2O

  17. Problem with Coal

  18. CO2 From Vehicles • The US used 9.15 million barrels of gasoline per day in 2005 • The US vehicle fleet adds 1.3 billion tons of CO2 into the air every year

  19. Alternative Energy - Politics • January’s State of the Union Address, President Bush proposed a “Twenty in Ten” plan to reduce gasoline usage in the US • The goal to reduce gasoline usage by 20% in the next 10 years • There will be mandatory standards to raise production of renewable fuels to 35 billion gallons per year by 2017

  20. Renewable Fuels • Renewable Fuels are derived from resources that are regenerative or cannot be practically depleted. • Biodiesel • Ethanol • Wind Power / Solar Power • Water Power • Geothermal Power

  21. Decarburization: A term scientists use to refer to the changing ratio of carbon to hydrogen atoms with each succeeding energy source. • Fuel wood: 10 carbon atoms to 1 hydrogen atom • Coal: 1 or 2 carbon atoms to 1 hydrogen atom • Oil: 1 carbon atom to every 2 hydrogen atoms • Natural gas: One carbon atom to 4 hydrogen atoms • So….. • Each successive energy source, when burnt, emits less CO2 than its predecessor. Pure hydrogen fuel would be best of all.

  22. Alternative Energy Sources(that do not emit carbon dioxide) • Solar Power • Hydropower • Geothermal Power • Wind Power • Hydrogen • Nuclear U235

  23. RENEWABLE ENERGY SOURCES INCLUDE BIOMASS, SOLAR, HYDROPOWER, GEOTHERMAL, WIND POWER AND HYDROGEN. Although biomass is a renewable fuel, its carbon-to-hydrogen ratio is not favorable. Burning wood, straw, animal feces, etc. releases a lot of CO2 into the atmosphere.

  24. SOLAR POWER

  25. Photovoltaic cells directly convert solar energy into electrical energy. The typical photovoltaic cell is a transparent wafer that contains a semiconductor. Sunlight energizes and causes the electrons in the semiconductor to flow, creating an electrical current.

  26. Solar panels come in many sizes and shapes. The semiconductor material can be made into paper-thin sheets that can be incorporated into traditional looking roofing materials or glass walls.

  27. In some areas, solar energy is a very good source of power. This is a large facility in California.

  28. The main drawback is that the sun must be shining 60% of the time. So these systems best work in regions with little cloud cover.

  29. HYDROPOWER • Downside: • Often need to construct • dams. This changes the flow pattern and ecology of rivers, and can block the amount of water farmers get. Could ultimately lead to ‘water wars’. • Some of the water is allowed to flow through huge pipes • at controlled rates, spinning turbines.

  30. Hydropower Water flowing from high elevations to lower elevations in rivers and streams can be controlled by dams and reservoirs. With hydropower, flowing water turns the turbines, which generate electricity. Ocean currents can also turn turbines. Because of increasing concern about the harmful environmental and social effect of large dams, there has been increasing pressure on the World Bank and other developmental agencies to stop funding new large-scale hydropower projects.

  31. GEOTHERMAL ENERGY

  32. Geothermal plants harness heat from the earth’s mantle. In some places there are steam and hot water pockets trapped near the surface. This stored energy can be use to heat buildings and it can be converted into electricity.

  33. In many places the earth’s crust is a constant 55 degrees Fahrenheit. Geothermal exchange devices can tap into the difference between the underground and surface temperatures, using a system of pipes and ducts to heat or cool a building.

  34. Wind power operates turbines that generate electricity • Since 1995, the use of wind turbines to produce electricity • has increased almost sevenfold. • It has been the world’s fastest-growing source of energy Europe is leading the way into the ‘age of wind energy’. • The DOE calls the Great Plains states of N. Dakota, S. Dakota, Nebraska, Kansas, Oklahoma and Texas the “Saudi Arabia of wind”. • By some calculations they have enough wind resources meet all the nation’s electricity needs.

  35. Some people find the wind turbines ‘very ugly’. They are sometimes a hazard to migrating birds and can be noisy.

  36. All these forms of clean, renewable energy (solar, water, geothermal, wind) can produce electricity. But it is difficult to store electricity. Electricity, by its very nature, FLOWS. Hydrogen can be stored and produce electricity using fuel cells.

  37. Storage Problem and Electricity All these forms of clean, renewable energy (solar, water, geothermal, wind) can produce electricity. But it is difficult to store electricity. Electricity, by its very nature, FLOWS. Hydrogen can be stored and produce electricity using fuel cells.

  38. Hydrogen • Hydrogen gas may be the best fuel to replace oil during the last half of this century. • Advantages: • Plentiful and can be produced from water • No CO2 emissions if produced from water • Easier to store than electricity • Safer than gasoline or natural gas • High efficiency (45 – 65%) in fuel cells.

  39. Burning Hydrogen • If hydrogen is burned as a fuel the product of the reaction is simply water vapor. 2H2 + O2 2H2O

  40. Obtaining Hydrogen • Although the element H is abundant, it is not found pure in nature. • The most common method of obtaining hydrogen is from steam reforming of natural gas. • This process also produces CO2 • Hydrogen can also be produced from the electrolysis of water. Electricity is used to split the water molecule into H2 and O2 • This process does not produces CO2

  41. Another hydrogen-production process being developed is the reforming of biomass and wastes via ‘pyrolysis’ or gasification of biomass such as agricultural residues (like peanut shells and banana skins), consumer wastes like grease, or biomass grown specifically for energy uses.

  42. SUMMARY • CO2 levels are increasing and contributing to Global Warming • Alternative forms of energy (esp. solar and wind) to generate electricity are becoming more economically attractive • Hydrogen gas can be used to produce electricity in a fuel cell and solve the storage problem with electricity • Adaptation and Mitigation are two primary responses to Global Warming • The US is promoting alternative energy - “Twenty in Ten” which will require using alternative forms of energy for gasoline

  43. RESOURCES • Rocky Mountain Institute www.rmi.org • http://www.greenenergyohio.org • http://www.rmi.org/sitepages/pid71.php#20H2myths • http://www.nrel.gov/hydrogen/proj_production_delivery.html • http://en.wikipedia.org/wiki/Greenhouse_effect#Basic_mechanism • The Hype About Hydrogen: Fact and Fiction in the Race to Save the Climate by Joseph J. Romm. 2004. • The Hydrogen Economy: The Creation of the Worldwide Energy Web and the Redistribution of Power on Earth by Jeremy Rifkin. 2003. • “Renewable Energy’s Achilles’ Heel” by Lisa Parker, Geotimes, February 2003. • “The Pyhsical Science Behind Climate Change” W. Collins, R. Colman, J. Haywood, M. Manning, and P. Mote, Scientific American, Aug 2007, pp 64 to 73.

  44. Resources • “FUELS AND GLOBAL WARMING: How Hydrogen Can Work with Other Alternative Energy Sources” – Power Point Presentation by By Linda Spurlock of Stark State College of Technology July, 2005 • Intergovernmental Panel on Climate Change (2001 report):