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Introduction to Energy Science

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Introduction to Energy Science

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    1. Introduction to Energy Science Wind for Schools Webinar: August 12th, 2010

    2. What is energy?

    3. Classes of Energy

    4. Potential Energy

    5. Potential Energy

    6. Potential Energy

    7. Potential Energy

    8. Kinetic Energy ..

    9. Kinetic Energy

    10. Kinetic Energy

    11. Kinetic Energy

    12. Kinetic Energy

    13. Energy Transfers

    14. Conservation of Energy To scientists, "conservation of energy" does not mean saving energy. Instead, the law of conservation of energy says that energy is neither created nor destroyed. When we use energy, it doesn't disappear. We change it from one form of energy into another. A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy. Solar cells change radiant energy into electrical energy. Energy changes form, but the total amount of energy in the universe stays the same Energy efficiency" is the amount of useful energy you get from any type of system. A perfectly energy-efficient machine would change all the energy put in it into useful work. In reality, converting one form of energy into another form always involves a loss of useable energy. In fact, most energy transformations are not very efficient. The human body is a good example. Your body is like a machine, and the fuel for your machine is food. Food gives you the energy to move, breathe, and think. But your body isn't very efficient at converting food into useful work. Your body is less than 5% efficient most of the time. The rest of the energy is lost as heat. To scientists, "conservation of energy" does not mean saving energy. Instead, the law of conservation of energy says that energy is neither created nor destroyed. When we use energy, it doesn't disappear. We change it from one form of energy into another. A car engine burns gasoline, converting the chemical energy in gasoline into mechanical energy. Solar cells change radiant energy into electrical energy. Energy changes form, but the total amount of energy in the universe stays the same Energy efficiency" is the amount of useful energy you get from any type of system. A perfectly energy-efficient machine would change all the energy put in it into useful work. In reality, converting one form of energy into another form always involves a loss of useable energy. In fact, most energy transformations are not very efficient. The human body is a good example. Your body is like a machine, and the fuel for your machine is food. Food gives you the energy to move, breathe, and think. But your body isn't very efficient at converting food into useful work. Your body is less than 5% efficient most of the time. The rest of the energy is lost as heat.

    15. Units of Energy Energy requires a force. Each form of energy has it’s own force: gravity, strong & weak nuclear forces, electrical, and kinetic forces. Kinetic Force = Mass x Acceleration Unit of force = 1 Newton = 1 Kilogram x 1 m/s Energy is a measurement of work accomplished by a force Energy = Force x Distance 1 Joule = 1 Newton x 1 Meter

    16. Energy and Power Energy is a quantity, like distance. 1 kilowatt-hour = 1000 Watts x 1 hour 1 kilowatt-hour = 3.6 x 106 Joules Power is a rate, like speed, it is the rate that energy is converted from one form to another. 1 Watt = 1 Joule / Second

    18. Laws of Thermodynamics First Law: In any transformation of energy from one form to another, the total quantity of energy remains unchanged. “Energy is neither created nor destroyed, it only changes forms.” Second Law: In all energy changes, the potential energy of the final state will be less than that of the initial state – (useful energy is always lost.) “Lost” energy is usually energy that has been converted to heat, but it could be noise (kinetic energy of air), or other forms of wasted energy.

    19. Efficiency The ratio of the amount of useable energy obtained to the amount of energy input is the efficiency of a process. This is usually expressed as a percent and it is always less than 100%.

    20. Energy definitions Primary Energy – amount of energy contained in the initial source of energy Delivered Energy – amount of useable energy delivered to the customer Useful Energy – amount of energy attributed to the amount of work accomplished

    21. What is Electricity?

    22. Energy Conversion Options for Electricity Non-Thermal Paths

    23. Energy Conversion Options for Electricity Thermal Paths

    24. Faraday Effect

    25. Electric Motor

    26. Model Electric Motor

    27. Electric Generator

    28. AC/DC (not the band) Alternating Current Large-scale generators produce AC Follows sine wave with n cycles per second 1, 2, 3-phase? US:120 V,60 Hz Europe: 240 V,50Hz Transforming ability Direct Current Batteries, Photovoltaics, fuel cells, small DC generators Charge in ONE direction Negative, Positive terminals Easy conversion AC to DC, not DC to AC

    30. Where do we get energy from and what do we use it for?

    31. Energy Sources Non Renewable Fossil Fuels Natural Gas Shale Oil Tar Sands Nuclear Fusion Fuel Renewable Solar Geothermal Tidal Most of Our Energy Is Nonrenewable In the United States, most of our energy comes from nonrenewable energy sources. Coal, petroleum, natural gas, propane, and uranium are nonrenewable energy sources. They are used to make electricity, to heat our homes, to move our cars, and to manufacture all kinds of products. These energy sources are called nonrenewable because their supplies are limited. Petroleum, for example, was formed millions of years ago from the remains of ancient sea plants and animals. We can't make more petroleum in a short time. Use of Renewable Energy Is Growing Renewable energy sources include biomass, geothermal energy, hydropower, solar energy, and wind energy. They are called renewable energy sources because they are replenished in a short time. Day after day, the sun shines, the wind blows, and the rivers flow. We use renewable energy sources mainly to make electricity. Most of Our Energy Is Nonrenewable In the United States, most of our energy comes from nonrenewable energy sources. Coal, petroleum, natural gas, propane, and uranium are nonrenewable energy sources. They are used to make electricity, to heat our homes, to move our cars, and to manufacture all kinds of products. These energy sources are called nonrenewable because their supplies are limited. Petroleum, for example, was formed millions of years ago from the remains of ancient sea plants and animals. We can't make more petroleum in a short time. Use of Renewable Energy Is Growing Renewable energy sources include biomass, geothermal energy, hydropower, solar energy, and wind energy. They are called renewable energy sources because they are replenished in a short time. Day after day, the sun shines, the wind blows, and the rivers flow. We use renewable energy sources mainly to make electricity.

    32. Solar Direct Sunlight Wind Hydroelectric Ocean Currents Ocean Thermal Gradients Biomass

    33. OECD Countries=Organization for Economic Co-Operation and Development AUSTRALIA: 7 June 1971 AUSTRIA: 29 September 1961 BELGIUM: 13 September 1961 CANADA: 10 April 1961 CZECH REPUBLIC: 21 December 1995 DENMARK: 30 May 1961 FINLAND: 28 January 1969 FRANCE: 7 August 1961 GERMANY: 27 September 1961 GREECE: 27 September 1961 HUNGARY: 7 May 1996 ICELAND: 5 June 1961 IRELAND: 17 August 1961 ITALY: 29 March 1962 JAPAN: 28 April 1964 KOREA: 12 December 1996 LUXEMBOURG: 7 December 1961 MEXICO: 18 May 1994 NETHERLANDS: 13 November 1961 NEW ZEALAND: 29 May 1973 NORWAY: 4 July 1961 POLAND: 22 November 1996 PORTUGAL: 4 August 1961 SLOVAK REPUBLIC: 14 December 2000 SPAIN: 3 August 1961 SWEDEN: 28 September 1961 SWITZERLAND: 28 September 1961 TURKEY: 2 August 1961 UNITED KINGDOM: 2 May 1961 UNITED STATES: 12 April 1961OECD Countries=Organization for Economic Co-Operation and Development AUSTRALIA: 7 June 1971AUSTRIA: 29 September 1961BELGIUM: 13 September 1961CANADA: 10 April 1961CZECH REPUBLIC: 21 December 1995DENMARK: 30 May 1961FINLAND: 28 January 1969FRANCE: 7 August 1961GERMANY: 27 September 1961GREECE: 27 September 1961HUNGARY: 7 May 1996ICELAND: 5 June 1961IRELAND: 17 August 1961ITALY: 29 March 1962JAPAN: 28 April 1964KOREA: 12 December 1996LUXEMBOURG: 7 December 1961MEXICO: 18 May 1994NETHERLANDS: 13 November 1961NEW ZEALAND: 29 May 1973NORWAY: 4 July 1961POLAND: 22 November 1996PORTUGAL: 4 August 1961SLOVAK REPUBLIC: 14 December 2000SPAIN: 3 August 1961SWEDEN: 28 September 1961SWITZERLAND: 28 September 1961TURKEY: 2 August 1961UNITED KINGDOM: 2 May 1961UNITED STATES: 12 April 1961

    34. World Primary Energy Consumption 10^15 = Quad Btus =quadrillion10^15 = Quad Btus =quadrillion

    35. 10^15 = Quad Btus =quadrillion 10^15 = Quad Btus =quadrillion

    36. Energy Consumption Versus GDP Energy intensity is a measure of the energy efficiency of a nation's economy. It is calculated as units of energy per unit of GDP. High energy intensities indicate a high price or cost of converting energy into GDP. Low energy intensity indicates a lower price or cost of converting energy into GDP. general standards of living and weather conditions in an economy. It is not atypical for particularly cold or hot climates to require greater energy consumption in homes and workplaces for heating (furnaces, or electric heaters) or cooling (air conditioning, fans, refrigeration). Energy intensity is a measure of the energy efficiency of a nation's economy. It is calculated as units of energy per unit of GDP. High energy intensities indicate a high price or cost of converting energy into GDP. Low energy intensity indicates a lower price or cost of converting energy into GDP. general standards of living and weather conditions in an economy. It is not atypical for particularly cold or hot climates to require greater energy consumption in homes and workplaces for heating (furnaces, or electric heaters) or cooling (air conditioning, fans, refrigeration).

    37. 2008 US Energy Flow

    38. US Energy Consumption Today, most of the energy consumed in the United States comes from fossil fuels — coal, petroleum, and natural gas, with crude oil-based petroleum as the dominant source of energy. Renewable energy resources supply a relatively small but steady portion, about 7% of U.S. total energy consumption. In the late 1950s, nuclear fuel began to be used to generate electricity, and in recent years has surpassed renewable energy sources.Today, most of the energy consumed in the United States comes from fossil fuels — coal, petroleum, and natural gas, with crude oil-based petroleum as the dominant source of energy. Renewable energy resources supply a relatively small but steady portion, about 7% of U.S. total energy consumption. In the late 1950s, nuclear fuel began to be used to generate electricity, and in recent years has surpassed renewable energy sources.

    39. http://tonto.eia.doe.gov/energyexplained/index.cfm?page=us_energy_usehttp://tonto.eia.doe.gov/energyexplained/index.cfm?page=us_energy_use

    40. http://tonto.eia.doe.gov/energyexplained/index.cfm?page=about_sources_of_energyhttp://tonto.eia.doe.gov/energyexplained/index.cfm?page=about_sources_of_energy

    41. http://tonto.eia.doe.gov/energyexplained/index.cfm?page=about_home http://tonto.eia.doe.gov/energyexplained/index.cfm?page=about_home

    42. Alaska Energy Consumption Energy use in each community is composed of three major components: electricity, space heating, and transportation. The relative level of use and cost for each of these components differs across Alaska. For instance, Anchorage residents pay comparatively less for electricity and space heating, but more for transportation due to heavy dependence on vehicle travel. Rural Alaskans see lower vehicle travel, but have much higher costs for heating oil and electricity.Energy use in each community is composed of three major components: electricity, space heating, and transportation. The relative level of use and cost for each of these components differs across Alaska. For instance, Anchorage residents pay comparatively less for electricity and space heating, but more for transportation due to heavy dependence on vehicle travel. Rural Alaskans see lower vehicle travel, but have much higher costs for heating oil and electricity.

    43. Alaska Energy Consumption The United States uses more energy per capita than any other country in the world, and Alaska as a state has the highest energy per capita energy use in the narration at 1112 MMBtu per person. This is three times higher than the national average of 333 MMBtu. This is due to our cold harsh winters, high level of air travel 43% of total energy is from jet fuel most of which is for international flights. In addition to the wellknown oil and natural gas resources on the North Slope and in Cook Inlet, Alaska’s proven coal reserves represent the 4th largest fossil energy resource in the world. Alaska also has significant undeveloped geothermal resources in the Aleutian Island volcanic arc, abundant untapped hydropower, wind, and biomass resources, and the majority of the tidal and wave power potential in the United States.In addition to the wellknown oil and natural gas resources on the North Slope and in Cook Inlet, Alaska’s proven coal reserves represent the 4th largest fossil energy resource in the world. Alaska also has significant undeveloped geothermal resources in the Aleutian Island volcanic arc, abundant untapped hydropower, wind, and biomass resources, and the majority of the tidal and wave power potential in the United States.

    44. Alaska Energy Consumption

    45. Energy diagram produced by the Alaska Center for Energy and Power based on data from ISER, the Alaska Department of Natural Resources, the U.S. Army Corp of Engineers, and the U.S. Energy Information Administration This is particularly evident in the production of electricity, where on average 66% of the energy used by our power plants is dissipated as waste heat. It is also interesting to note that since 2001 (the last time ISER completed an energy flow diagram for the state), residential energy use increased by 18% while the state population increased by only 7%. Alaska’s total energy consumption in 2006 = 419 trillion btus divided into the following sectors: • Residential 45 Trillion BTUs • Commercial 45 Trillion BTUs • Industrial 26 Trillion BTUs • Transportation 263 Trillion BTUsEnergy diagram produced by the Alaska Center for Energy and Power based on data from ISER, the Alaska Department of Natural Resources, the U.S. Army Corp of Engineers, and the U.S. Energy Information Administration This is particularly evident in the production of electricity, where on average 66% of the energy used by our power plants is dissipated as waste heat. It is also interesting to note that since 2001 (the last time ISER completed an energy flow diagram for the state), residential energy use increased by 18% while the state population increased by only 7%. Alaska’s total energy consumption in 2006 = 419 trillion btus divided into the following sectors: • Residential 45 Trillion BTUs • Commercial 45 Trillion BTUs • Industrial 26 Trillion BTUs • Transportation 263 Trillion BTUs

    46. The graph below shows the gross consumption of energy in Alaska from 1960 through 2006. Oil and gas production began in Cook Inlet during the late 1960s, and by the early 1980s natural gas was the predominant source of energy used in Alaska. When oil and gas production began on the North Slope in the late 1970s, natural gas consumption by industrial users increased dramatically because it was used to power North Slope operations. All other fuels, including diesel, motor gasoline, jet fuel, and coal, have contributed relatively stable shares of total energy consumption per capita in the state.The graph below shows the gross consumption of energy in Alaska from 1960 through 2006. Oil and gas production began in Cook Inlet during the late 1960s, and by the early 1980s natural gas was the predominant source of energy used in Alaska. When oil and gas production began on the North Slope in the late 1970s, natural gas consumption by industrial users increased dramatically because it was used to power North Slope operations. All other fuels, including diesel, motor gasoline, jet fuel, and coal, have contributed relatively stable shares of total energy consumption per capita in the state.

    49. Climate Change Logic The Burning of fossil fuels cause carbon dioxide concentrations to rise. Carbon dioxide is a greenhouse gas. Increasing the greenhouse effect increases average global temperatures (among other impacts) Greenhouse gases include carbon dioxide, methane, and nitrous oxide; each gas has dif- ferent physical properties; it’s conventional to express all gas emissions in “equivalent amounts of carbon dioxide,” where “equivalent” means “having the same warming effect over a period of 100 years.” One ton ofcarbon-dioxide-equivalentmaybeabbreviatedas“1 t CO2e,”andone billion tons (one thousand million tons) as “1 Gt CO2 e” (one gigaton). In this book 1 t means one metric ton (1000 kg).Greenhouse gases include carbon dioxide, methane, and nitrous oxide; each gas has dif- ferent physical properties; it’s conventional to express all gas emissions in “equivalent amounts of carbon dioxide,” where “equivalent” means “having the same warming effect over a period of 100 years.” One ton ofcarbon-dioxide-equivalentmaybeabbreviatedas“1 t CO2e,”andone billion tons (one thousand million tons) as “1 Gt CO2 e” (one gigaton). In this book 1 t means one metric ton (1000 kg).

    50. Carbon dioxide (CO2) concentrations (in parts per million) for the last 1100 years, measured from air trapped in ice cores (up to 1977) and directly in Hawaii (from 1958 onwards).I think something new may have happened between 1800 AD and 2000 AD. I’ve marked the year 1769, in which James Watt patented his steam engine. (The first practical steam engine was invented 70 years earlier in 1698, but Watt’s was much more efficient.) Does “scep- tic” mean “a person who has not even glanced at the data”? Energy Information Administration www.eia.doe.govCarbon dioxide (CO2) concentrations (in parts per million) for the last 1100 years, measured from air trapped in ice cores (up to 1977) and directly in Hawaii (from 1958 onwards).I think something new may have happened between 1800 AD and 2000 AD. I’ve marked the year 1769, in which James Watt patented his steam engine. (The first practical steam engine was invented 70 years earlier in 1698, but Watt’s was much more efficient.) Does “scep- tic” mean “a person who has not even glanced at the data”?

    51. 1000 years of CO2 Concentration

    52. 1000 Years of Temperature Changes

    56. Every Year an Average Coal Plant Releases 3,700,000 tons of CO2 10,000 tons of SO2. 500 tons of particulates 10,200 tons NOx 720 tons of CO 220 tons of volatile organic compounds (VOC) 170 pounds of mercury 225 pounds of arsenic 114 pounds of lead And there are over 600 of them in the US. Source: Union of Concerned Scientists: www.ucsusa.org

    57. Types of Pollutants CO2 – Global Warming CO – Health problem PM –Respiratory and heart disease, haze SOx – Acid Rain, respiratory illness, haze NOx – Ozone formation, acid rain, smog, nutrient loading, global warming Mercury – Neurotoxin Lead – Neurotoxin Arsenic - Poison VOCs – Numerous health problems Ozone – Health problems, damage to flora & fauna Hundreds of other toxic chemicals

    61. Power in the Wind Power = Work / t = Kinetic Energy / t = ½mV2 / t = ½(?Ad)V2/t = ½?AV2(d/t) = ½?AV3

    62. A couple things to remember… Swept Area – A = pR2 (m2) Area of the circle swept by the rotor. ? = air density – in Colorado its about 1-kg/m3

    63. Example – Calculating Power in the Wind V = 5 meters (m) per second (s) m/s ? = 1.0 kg/m3 R = .2 m >>>> A = .125 m2 Power in the Wind = ½?AV3 = (.5)(1.0)(.125)(5)3 = 7.85 Watts Units = (kg/m3)x (m2)x (m3/s3) = (kg-m)/s2 x m/s = N-m/s = Watt

    64. Wind Turbine Power Power from a Wind Turbine Rotor = Cp½?AV3 Cp is called the power coefficient. Cp is the percentage of power in the wind that is converted into mechanical energy. What is the maximum amount of energy that can be extracted from the wind?

    65. Betz Limit when a = 1/3 Vax = 2/3V1 V2 = V1/3 Actuator Disk Model of a Wind Turbine Where Free stream velocity, V1 Wake velocity, V2=(1 2a) Velocity at rotor, Vax = V1(1-a) Induction factor, a

    67. Reality Check What’s the most power the .6 ft turbine in the example can produce in a 5 m/s wind? 7.85 Watts x .5926 (Betz Limit) = 4.65 Watts

    69. Tip-Speed Ratio Tip-speed ratio is the ratio of the speed of the rotating blade tip to the speed of the free stream wind.

    70. Blade Planform Types Which should work the best??

    71. Airfoil Nomenclature wind turbines use the same aerodynamic principals as aircraft

    72. Airfoil Behavior The Lift Force is perpendicular to the direction of motion. We want to make this force BIG. The Drag Force is parallel to the direction of motion. We want to make this force small.

    74. Gradual curves Sharp trailing edge Round leading edge Low thickness to chord ratio Smooth surfaces Making Good Airfoils

    78. Number of Blades – One Rotor must move more rapidly to capture same amount of wind Gearbox ratio reduced Added weight of counterbalance negates some benefits of lighter design Higher speed means more noise, visual, and wildlife impacts Blades easier to install because entire rotor can be assembled on ground Captures 10% less energy than two blade design Ultimately provide no cost savings

    79. Number of Blades - Two Advantages & disadvantages similar to one blade Need teetering hub and or shock absorbers because of gyroscopic imbalances Capture 5% less energy than three blade designs

    80. Number of Blades - Three Balance of gyroscopic forces Slower rotation increases gearbox & transmission costs More aesthetic, less noise, fewer bird strikes

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