Chapter 17: Energy: Some Basics

1. Chapter 17: Energy: Some Basics

2. Energy Crisis in Ancient Greece and Rome • Greeks and Romans used wood to heat there homes. • As local supplies ran out had to bring it in from farther away. • Eventually both societies learned to build houses south facing • Allows sun to heat house in winter • Sustainable • In Rome laws pasted to protect a person’s right to solar energy.

4. Energy Today and Tomorrow • Energy situation facing the US today is similar to that faced by Greeks and Romans. • Use of wood peaked 1880s • Coal use peaked 1920 • Reaching the peak of oil and gas use • The decisions we make today will affect energy use for generations.

5. Energy Basics • To understand energy it is easiest to begin with the idea of force • We have all exerted force by pushing or pulling • The strength of force can be measured by how much it accelerates an object • Think of pushing a car uphill

7. Energy Basics • In physicists’ terms • Exerting force over a distance moved is work • Work is the product of a force times a distance • Energy is the ability to do work • When the car id higher on the hill the potential energy of the car has increased • Energy can be converted from one kind to another • The total energy conserved • First law of thermodynamics

8. Energy Basics • To illustrate the conservation and conversion of energy think of a tire swing • At highest position all energy is stored potential energy • At lowest position all energy is kinetic energy • Energy of motion • With each swing friction slows the swing generating heat energy • Eventually all the energy converted to heat and the swing stops

10. Energy Basics • Energy quality • The ability of the energy to do work • The higher quality of the energy, the more easily it can be converted to work. • The lower the energy quality, the more difficult it is to convert to work. • Second law of thermodynamics • Energy always tends to go from a more usable (higher-quality) form to a less usable (lower-quality) form. • When you use energy, you lower its quality.

11. Energy Efficiency • Two fundamental types of energy efficiencies are derived from the first and second laws of thermodynamics: • the first-law efficiency and the second-law efficiency. • First-law efficiency deals with the amount of energy without any consideration of the quality or availability of the energy.

12. Energy Efficiency • Second-law efficiency refers to how well matched the energy end use is with the quality of the energy source. • Low values indicate where improvements in energy technology and planning may save significant amounts of high-quality energy.

14. Energy Efficiencies • Electricity generating plants have nearly the same first-law and second-law efficiencies. • Generating plants are examples of heat engines. • Produces work from heat. • Most of the electricity generated in the world today comes from heat engines • Use nuclear fuel, coal, gas, or other fuels.

15. Energy Source and Consumption • Industrialized countries small percentage of the world’s population, but consume a disproportionate share of the total energy produced in the world. • E.g. US with only 5% of the world’s population, uses approximately 25% of the total energy consumed.

16. Fossil Fuels and Alternative Energy Sources • 90% of the energy consumed in the US comes from fossil fuels • Petroleum, natural gas, and coal. • They are essentially nonrenewable. • Other sources of energy • Include geothermal, nuclear, hydropower, and solar • Referred to as alternative energy sources. • Solar and wind, are not depleted by consumption and are known as renewable energy.

17. Energy Consumption in the US Today • US dependent on the three major fossil fuels • coal; natural gas; and petroleum. • From 1950 to late-1970s, energy consumption increased tremendously • From 30 exajoules to 80 exajoules. • Since about 1980, energy consumption has increased by only about 20 exajoules. • Suggests that policies to improve energy conservation through efficiency improvements have been at least partially successful.

20. Energy Consumption in the US Today • Energy losses are associated with • the production of electricity and transportation. • Most occur through the use of heat engines • Looking at the generalized energy flow of the US for a particular year • We imported considerably more oil than we produced • Consumption distributed in three sectors: residential/commercial, industrial, and transportation. • We remain dangerously vulnerable to changing world conditions affecting the production of oil.

23. Energy Conservation, Increased Efficiency and Cogeneration • Conservation of energy • Simply getting by with less demand for energy. • Increased energy efficiency • Involves designing equipment to yield more energy output from a given amount of input energy (first-law efficiency) • Better matches between energy source and end use (second-law efficiency).

24. Energy Conservation, Increased Efficiency and Cogeneration • Cogeneration • Processes designed to capture and use waste heat rather than release it as a thermal pollution. • Using that waste heat, can increase the overall efficiency of a typical power plant from 33% to as much as 75% • Could provided an estimated 10% of the power capacity of the US

26. Building Design • A spectrum of possibilities exists for increasing energy efficiency and conservation in residential buildings. • Design and construct homes that minimize the energy consumption • Design buildings to take advantage of passive solar potential • For older homes:insulation, caulking, weather stripping, installation of window coverings, storm windows, and regular maintenance.

27. Industrial Energy • Industrial production of goods continues to grow significantly. • U.S. industry consumes about one-third of the energy produced. • More industries are using co-generation and more energy-efficient machinery.

28. Automobile design • Early 1970s, the average US automobile got 14 mpg. • By 1996, the average was 28 mpg for highway driving. • Fuel consumption rates did not improve much from 1996 to 1999. • In 2004 many vehicles sold were SUVs and light trucks with fuel consumption of 10–20 mpg. • A loophole in regulations permits poorer fuel consumption • SUVs declined in 2006.

29. Automobile design • Today, some hybrid (gasoline-electric) vehicles exceeds 90 mpg on the highway and 60 mpg in the city. • Improvement has several causes: • Increased efficiency and resulting conservation of fuel • Cars that are smaller, w/ engines constructed of lighter materials • Combination of a fuel-burning engine with an electric motor

30. Values, Choices, and Energy Conservation • Ways of modifying behavior to conserve energy include the following: • Ride a bike, walk, or take a bus or train to work. • Using carpools to travel to and from work or school • Purchasing a hybrid car (gasoline-electric) • Turning off lights when leaving rooms • Taking shorter showers (conserves hot water) • Putting on a sweater and turning down the thermostat

31. Values, Choices, and Energy Conservation • Using energy-efficient compact florescent lightbulbs • Purchasing energy-efficient appliances • Sealing drafts in buildings with weather stripping and caulk • Better insulating your home • Washing clothes in cold water whenever possible • Purchasing local foods to reduce energy in transport • Using powerstrips and turning them off when not in use

32. Energy Policy • U.S. energy policy during the past half-century has not moved us closer to energy self-sufficiency. • We import more oil than ever. • In the late 1990s, the US spent $2 billion per year on R and D for energy. • By comparison, $45 billion per year went to R and D for the military.

34. Energy Policy Act of 2005 • Some of the provisions are as follows. • 1. Promotes conventional energy sources • 2. Promotes nuclear power • 3. Encourages alternative energy • 4. Promotes conservation measures • 5. Promotes research • 6. Provides for energy infrastructure

35. Hard Path vs. Soft Path • Hard path involves finding greater amounts of fossil fuels and building larger power plants. • Continuing the past emphasis on quantity of energy used. • Requires no new thinking; no realignment of political, economic, or social conditions; and little anticipation of coming reductions oil.

36. Hard Path vs. Soft Path • According to hard-path proponents, we should • 1. Let the energy industry develop the available energy resources • 2. Let industry, free from government regulations, provide a steady supply of energy with less total environmental damage.

37. Hard Path vs. Soft Path • The second road of energy policy is called the soft path. • It involves energy alternatives that emphasize • energy quality, are renewable, are flexible, and are environmentally more benign than those of the hard path.

38. Hard Path vs. Soft Path • These alternatives have several characteristics: • They rely heavily on renewable energy resources, such as sunlight, wind, and biomass. • They are diverse and are tailored for maximum effectiveness under specific circumstances. • They are flexible, accessible, and understandable to many people. • They are matched in energy quality, geographic distribution, and scale to end-use needs.

39. Energy for Tomorrow • Future changes in population densities as well as intensive conservation measures will probably change existing patterns of energy use. • To stabilize the climate in terms of global warming, use of energy from fossil fuels would need to be cut by about 50%. • Reductions in energy use need not be associated w/ lower quality of life.

41. Energy for Tomorrow • What is needed is increased conservation and more efficient use of energy: • More energy-efficient land-use planning that maximizes the accessibility of services and minimizes the need for transportation. • Agricultural practices and personal choices that emphasize • 1. Eating more locally grown foods • 2. Eating more vegetables, beans, and grains. • Industrial guidelines for factories that promote energy conservation and minimize production of waste.

42. Integrated, Sustainable Energy Management • Integrated energy management recognizes that no single energy source can provide all the energy required. • Range of options that vary from region to region will have to be employed. • The mix of technologies and sources of energy will involve both fossil fuels and alternative, renewable sources.

43. Integrated, Sustainable Energy Management • A basic goal is to move toward sustainable energy development, implemented at the local level. • Would have the following characteristics: • It would provide reliable sources of energy. • It would not cause destruction or serious harm to our global, regional, or local environments. • It would help ensure that future generations inherit a quality environment with a fair share of the Earth’s resources.

44. Integrated, Sustainable Energy Management • A good energy plan is part of an aggressive environmental policy with the goal of producing a quality environment for future generations. • A good plan should do the following: • Provide for sustainable energy development. • Provide for aggressive energy efficiency and conservation.

45. Integrated, Sustainable Energy Management • Provide for the diversity and integration of energy sources. • Provide for a balance between economic health and environmental quality. • Use second-law efficiencies as an energy policy tool.

46. Integrated, Sustainable Energy Management • The global pattern of ever-increasing energy consumption led by the US cannot be sustained w/o a new energy paradigm • Includes changes in human values rather than a breakthrough in technology. • Choosing to own fuel-efficient automobiles and living in more energy-efficient homes are consistent with a sustainable energy system.