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 had not increased since 1985.
In May 2009, President Obama increased the standards 5% per year towards a goal of 35.5 MPG by 2016.
This represents an average of an 8 MPG increase.
Still well below Europe and Japan.

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

13. More Energy-Efficient Vehicles Are on the Way
Hybrid cars accounted for 3% cars on the road in 2009.
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 stricter government regulations on CO2 emissions.

14. 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 2012)
Use of rare earth metals for battery construction

15. 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

16. 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.

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

18. 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.

19. 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

20. 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.

21. Solar Power

22. We Can Heat Buildings and Water with Solar Energy
Passive solar heating system
Absorbs and stores heat from the sun directly within a structure without the need for pumps to distribute the heat.
House faces South

23. 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

24. Trade-Offs: Passive or Active Solar Heating

25. We Can Cool Buildings Naturally
Technologies available
Superinsulation and high-efficiency windows
Overhangs or awnings on windows
Light-colored roof
Reflective insulating foil in an attic
Geothermal pumps
Plastic earth tubes underground

26. 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.

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

28. 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.

29. We Can Use Solar Cells to Produce Electricity
Their costs are high, but expected to fall with mass production, new designs, nanotechnology.
Solar cells can be used in rural villages with ample sunlight who are not connected to an electrical grid.
Mostly for pumping water

30. Trade-Offs: Solar Cells, Advantages and Disadvantages
Solar cells currently only 0.2% of the world’s electricity
Solar power has the largest POTENTIAL for supplying electrical power to the world.

31. 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.

32. Hyrdopower

33. 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.

34. We Can Produce Electricity from Falling and Flowing Water

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

36. 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).