1. Energy Efficiency and Renewable Energy
Chapter 16

2. 16-1 Why Is Energy Efficiency an Important Energy Resource?
Concept We could save as much as 43% of all the energy we use by improving energy efficiency.

3. We Waste Huge Amounts of Energy
Energy conservation
A decrease in energy use as a result of a decrease in the amount of wasted energy – “Use less”
Energy efficiency
The measure of work we can get out of a unit of energy we use – “Use it better”
Four widely used devices waste large amounts of energy:
Incandescent light bulb: 95% lost as heat
Internal combustion engine: 94% of the energy from fuel wasted
Nuclear power plant: 92% of energy is wasted through nuclear fuel and energy needed for waste management
Coal-burning power plant: 75-80% of the energy released by burning coal is lost

4. Flow of Commercial Energy through the U.S. Economy
84% of all commercial energy used in the U.S. is wasted.
41% wasted due to the 2nd law of thermodynamics.
Only 9% of the total energy put into the U.S. economy results in useful energy.

5. Advantages of Reducing Unnecessary Energy Waste

6. 16-2 How Can We Cut Energy Waste?
Concept We have a variety of technologies for sharply increasing the energy efficiency of industrial operations, motor vehicles, and buildings.

7. We Can Save Energy and Money in Industry
Industry accounts for 38% of U.S. energy consumption. It can save energy and money by:
Produce both heat and electricity from one energy source (cogeneration or combined heat and power, CHP)
Use more energy-efficient electric motors
Recycle materials
Switch from low-efficiency incandescent lighting to higher-efficiency compact fluorescent (CFL) and LED lighting
Update the old/wasteful electrical grid system (how electricity is transmitted from the power plant to the consumer)
Utility companies promote use of energy
Instead, should promote conservation

8. We Can Save Energy and Money in Transportation
Transportation accounts for 2/3 of U.S. oil demand and is a major source of air pollution.
We can save energy in transportation by increasing fuel efficiency and making vehicles from lighter and stronger materials.
Corporate Average Fuel Economy (CAFE) standards
The average fuel economy, in miles per gallon (mpg), of a manufacturer’s fleet of passenger cars and/or light trucks
Fuel-efficient cars are on the market
Tax breaks for buying fuel-efficient cars

9. Average Fuel Economy of New Vehicles Sold in the U. S
Average Fuel Economy of New Vehicles Sold in the U.S. and Other Countries
CAFE standards did not increased from 1985 to 2009.
In 2009, the Obama administration increased the standards to 35.5 MPG by 2016.
In 2012, the Obama administration increased the standards again to 54.5 by 2025.
This represents the doubling of the original CAFE standards

10. More Energy-Efficient Vehicles Are on the Way
Hybrid vehicles have two types of engines working together to achieve higher gas mileage (15-70% more) and lower engine exhaust emissions:
A standard gas powered engine
An electric motor assist powered by a rechargeable nickel-metal hydride (NiMH) battery pack
Gasoline-electric hybrid car
Mostly gas…some electric
Plug-in hybrid electric vehicle
Mostly electric…some gas
Electric vehicle (EV’s)
ALL electric

11. Solutions: A Hybrid-Gasoline-Electric Engine Car and a Plug-in Hybrid Car

12. More Energy-Efficient Vehicles Are on the Way
Hybrid cars accounted for 3.5% cars on the road in 2012.
Up from than 1% in 2007
Typically cost $3-4,000 more than non-hybrid models.
Plug-in hybrids can get twice the mileage of gasoline-electric hybrid cars, but…
How is the electricity generated?
Electricity from coal or nuclear power plants = JUST AS BAD
Electricity produced by wind or solar energy = GOOD
Analysts estimate that hybrid cars could make up as much as 20% of the car market by the year 2020.
The boost in sales will be pushed by consumer demands and possible government regulations on CO2 emissions.

13. Science Focus: The Search for Better Batteries
Current obstacles to hybrid or electric vehicles:
Storage capacity of battery
Currently about 100 mile range
Charging time
8 hours for a Nissan Leaf (available NOW)
3 hours for a Ford Focus EV (available in 2013)
Use of rare earth metals for battery construction

14. We Can Design Buildings That Save Energy and Money
Green architecture
Makes use of passive solar heating, natural lighting, natural ventilation, rain water collection, cogeneration of heat/electricity, geothermal heat pumps, and recycled building materials
Living or green roofs
Superinsulation
U.S. Green Building Council’s Leadership in Energy and Environmental Design (LEED)
Graded on 100 possible points:
Certified points
Silver points
Gold points
Platinum - 80 points up

15. We Can Save Energy and Money in Existing Buildings
Insulate and plug leaks
Use energy-efficient windows
Stop other heating and cooling losses
Heat houses more efficiently
Heat water more efficiently
Use energy-efficient appliances
Use energy-efficient lighting
About 1/3 of the heated air in typical U.S. homes and buildings escapes through closed windows, holes, and cracks.

16. Individuals Matter: Ways in Which You Can Save Money Where You Live

17. Why Are We Still Wasting So Much Energy?
Low-priced fossil fuels and few government tax breaks or other financial incentives for saving energy promote energy waste.

18. We Can Use Renewable Energy in Place of Nonrenewable Energy Sources
A variety of renewable-energy resources are available but their use has been hindered by a lack of government support (subsides) compared to nonrenewable fossil fuels and nuclear power.
Direct solar
Moving water
Wind
Geothermal

19. 16-3 What Are the Advantages and Disadvantages of Solar Energy?
Concept Passive and active solar heating systems can heat water and buildings effectively, and the costs of using direct sunlight to produce high-temperature heat and electricity are coming down.

20. Solar Power

21. We Can Heat Buildings and Water with Solar Energy
Passive solar heating system
Absorbs/stores heat from the sun within a structure without the need for pumps to distribute the heat.
Lots of windows on the south side of house

22. We Can Heat Buildings and Water with Solar Energy
Active solar heating system
Pumping a liquid such as water or an oil through rooftop collectors
Can also be used to provide hot water

23. Trade-Offs: Passive or Active Solar Heating

24. We Can Use Sunlight to Produce High-Temperature Heat and Electricity
Solar thermal systems
Sunlight is directed towards a central tower where and oil absorbs the heat and is used to create high temperature steam to turn a turbine.
Large arrays of solar collectors in sunny deserts
Costs are high and energy yield is low.

25. Solutions: Woman in India Uses a Solar Cooker
Solution to the “fuel wood crisis”?

26. We Can Use Solar Cells to Produce Electricity
Photovoltaic (PV) cells (solar cells)
Convert solar energy to electric energy
Can be made in all shapes and sizes and can be included in the building design and construction.

27. We Can Use Solar Cells to Produce Electricity
Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid.
Mostly for pumping water

28. We Can Use Solar Cells to Produce Electricity
Solar cells currently account for less than 1% of the world’s electricity
Solar power has the largest POTENTIAL for supplying electrical power to the world.
Gigawatts of solar generation
Projected growth of solar generation

29. Trade-Offs: Solar Cells, Advantages and Disadvantages
Photovoltaic cells costs are high but are quickly falling as a result of mass production, new designs, and nanotechnology.

30. 16-4 Advantages and Disadvantages of Producing Electricity from the Water Cycle
Concept Water flowing over dams, tidal flows, and ocean waves can be used to generate electricity, but environmental concerns and limited availability of suitable sites may limit the use of these energy resources.

31. Hydropower

32. We Can Produce Electricity from Falling and Flowing Water
Hydropower
Build a high dam across a large river
Water builds up into a reservoir
Let water flow through large pipes and turn turbines to produce electricity
World’s leading renewable energy source used to produce electricity
16% of the world’s electricity
99% in Norway, only 7% in the U.S.

33. We Can Produce Electricity from Falling and Flowing Water

34. Trade-Offs: Large-Scale Hydropower, Advantages and Disadvantages

35. Tides and Waves Can Be Used to Produce Electricity
Ocean tides and waves and temperature differences between surface and bottom waters in tropical waters are not expected to provide much of the world’s electrical needs.
Few suitable sites
High costs
Equipment corrosion
Only two large tidal energy dams are currently operating: one in La Rance, France and Nova Scotia’s Bay of Fundy (where the tidal difference can be as high as 63 feet).

36. 16-5 Advantages and Disadvantages of Producing Electricity from Wind
Concept When environmental costs of energy resources are included in market prices, wind energy is the least expensive and least polluting way to produce electricity.

37. Wind

38. Using Wind to Produce Electricity Is an Important Step toward Sustainability
Wind power is a very promising energy resource because it is abundant, inexhaustible, widely distributed, cheap, clean, and emits no greenhouse gases.
Second fastest-growing source of energy
Much of the world’s potential for wind power remains untapped.
Capturing only 20% of the wind energy at the world’s best energy sites could meet all the world’s energy demands.

39. Solutions: Wind Turbine and Wind Farms on Land and Offshore
Wind: indirect form of solar energy
Captured by turbines
Converted into electrical energy
They are also used interconnected in arrays on wind farms – both on land and offshore.

40. Solutions: Wind Turbine and Wind Farms on Land and Offshore

41. Using Wind to Produce Electricity Is an Important Step toward Sustainability
Wind power is capable of becoming a major contributor to America's electricity supply over the next three decades.
A U.S. Department of Energy report looks closely at the goal of reaching 20% wind energy by 2030.
According to U.S. Department of Energy, a network of wind farms in just four states could meet all U.S. electricity means.

42. Producing Electricity from Wind Energy Is a Rapidly Growing Global Industry
The textbook says that Germany is the world’s top wind producer, but that data is out of date.

43. Producing Electricity from Wind Energy Is a Rapidly Growing Global Industry
Back in 2009, Iowa generated 20% of its electricity from renewable sources (14.5% from wind)
As of 2012, Iowa produces 20% of all the electricity generated in the state from wind ranking it 1st in the nation and 2nd in the world!

44. Trade-Offs: Wind Power, Advantages and Disadvantages

45. 16-6 Advantages and Disadvantages of Biomass as an Energy Source
Concept 16-6A Solid biomass is a renewable resource, but burning it faster than it is replenished produces a net gain in atmospheric greenhouse gases, and creating biomass plantations can degrade soil biodiversity.
Concept 16-6B Liquid biofuels derived from biomass can be used in place of gasoline and diesel fuels, but creating biofuel plantations could degrade soil and biodiversity and increase food prices and greenhouse gas emissions.

46. Biomass

47. We Can Get Energy by Burning Solid Biomass
Plant materials and animal wastes can be burned to provide heat/electricity or converted into biofuels.

48. We Can Get Energy by Burning Solid Biomass
As the population increases, fuelwood is being harvested at unsustainable rates in developing countries. It is used for:
Cooking
Heat
Sterilization of water

49. We Can Get Energy by Burning Solid Biomass
Through the biomass energy cycle, CO2 is “recycled”.
No “new” CO2 is added to the atmosphere.

50. Trade-Offs: Solid Biomass, Advantages and Disadvantages

51. We Can Convert Plants and Plant Wastes to Liquid Biofuels
Motor vehicles can run on ethanol, biodiesel, and methanol produced from plants and plant wastes.
Liquid biofuels
Biodiesel
Ethanol
Biggest producers of biofuel:
Brazil (45% of cars run on ethanol)
The United States
The European Union (large biodiesel production/use)
China

52. Case Study: Is Biodiesel the Answer?
Biodiesel production from vegetable oil from a variety of different plants or even from animal fats.
95% produced by The European Union
Biodiesel has the potential to supply about 10% of the U.S.’s diesel fuel needs

53. Case Study: Is Ethanol the Answer?
Ethanol involves fermenting the sugars in certain crops such as sugarcane, corn, and switchgrass and agricultural, forestry and municipal wastes.
The ethyl alcohol is then added to gasoline.
Regular ethanol = 15% ethanol & 85% gasoline
E85 = 85% ethanol & 15% gasoline

54. Case Study: Is Ethanol the Answer?
Cellulosic ethanol: alternative to corn ethanol
Sources: switchgrass, crop residues, municipal wastes

55. Case Study: Is Ethanol the Answer?
Brazil: “Saudi Arabia of sugarcane”
Saved $50 billion in oil import costs since the 1970s
United States: ethanol from corn
Competition with the food industry over the use of corn
Drive food prices up?
Processing all corn grown in the U.S. into ethanol would cover only about 55 days of current driving.
10-23% pure ethanol makes gasohol which can be run in conventional motors.
85% ethanol (E85) must be burned in flex-fuel cars.

56. Trade-Offs: Biodiesel and Ethanol Fuel

57. 16-7 What Are the Advantages and Disadvantages of Geothermal Energy?
Concept 16-7 Geothermal energy has great potential for supplying many areas with heat and electricity and generally has a low environmental impact, but locations where it can be exploited economically are limited.

58. GEOTHERMAL

59. Getting Energy from the Earth’s Internal Heat
Geothermal energy is heat stored in the soil, underground rock, and fluids in the earth’s mantle.
We can use geothermal energy stored in the earth’s mantle to heat and cool buildings.
A geothermal heat pump (GHP) can heat and cool a house by exploiting the difference between the earth’s surface and underground temperatures.

60. Getting Energy from the Earth’s Internal Heat
Depending on latitude, starting at a depth of 5-10 feet, the temperature remains a constant 50-55˚ F.
The house is heated in the winter by transferring heat from the ground into the house.
In the summer the heat from the house is discharged into the ground.

61. Getting Energy from the Earth’s Internal Heat
Open Loop systems actually pump water from an underground aquifer through the geothermal heat pump and then discharge that water to a drainage ditch or pond.
Many times a re-injection well is used to return the water to the aquifer.

62. Getting Energy from the Earth’s Internal Heat
Closed Loop systems involve passing an antifreeze solution through a closed loop of tubes or pipes.
The same liquid is re-circulated over and over

63. Getting Energy from the Earth’s Internal Heat
Deeper more concentrated hydrothermal reservoirs can be used to heat homes and buildings and spin turbines to make electricity.
Iceland
Geothermal energy: two problems
High cost of tapping large-scale hydrothermal reservoirs
Dry- or wet-steam geothermal reservoirs could be depleted

64. Trade Offs: Geothermal Energy, Advantages and Disadvantages

65. 16-8 The Advantages and Disadvantages of Hydrogen as an Energy Source
Concept Hydrogen fuel holds great promise for powering cars and generating electricity, but to be environmentally beneficial, it would have to be produced without the use of fossil fuels.

66. HYDROGEN

67. Hydrogen Is a Promising Fuel but There Are Challenges
Some energy experts view hydrogen gas as the best fuel to replace oil during the last half of the century, but there are several hurdles to overcome:
Hydrogen is chemically locked up in water and organic compounds (electrolysis can get it out).
It takes energy and money to produce it so the net energy is low.
CO2 levels dependent on the method of hydrogen production
No reduction of CO2 emissions if hydrogen is obtained by using fossil fuels.

68. Hydrogen Is a Promising Fuel but There Are Challenges
Fuel cells are the best way to use hydrogen.
Fuel-efficient vehicles powered by a fuel cell that runs on hydrogen gas are being developed.
Combines hydrogen gas (H2) and oxygen gas (O2) to produce electricity.
(2H2+O2  2H2O)
Emits no air pollution or CO2 if the hydrogen is produced from renewable energy sources.
Only water vapor! 68

69. Fuel Cell Vehicles 69

70. Trade-Offs: Hydrogen, Advantages and Disadvantages

71. 16-9 How Can We Make a Transition to a More Sustainable Energy Future?
Concept We can make a transition to a more sustainable future if we greatly improve energy efficiency, use a mix of renewable energy resources, and include environmental costs in the market prices of all energy resources.

72. Choosing Energy Paths
A more sustainable energy policy would improve energy efficiency, rely more on renewable energy, and reduce the harmful effects of fossil fuels and nuclear energy.
There will be a gradual shift from large, centralized macropower systems to smaller, decentralized micropower systems.
90% of electricity is lost in the transmission from place to place.

73. Choosing Energy Paths
Governments can use a combination of subsidies, tax breaks, rebates, taxes and public education to promote or discourage use of various energy alternatives:
Can keep prices artificially low to encourage selected energy resources.
Can keep prices artificially high to discourage other energy resources.
Emphasize consumer education.

74. Solutions: Making the Transition to a More Sustainable Energy Future

75. Total Costs of Electricity from Different Sources in 2004