2. This lecture will help you understand:
The major sources of renewable energy
Solar energy
Wind energy
Geothermal energy
Ocean energy
Hydrogen fuel cells
Housekeeping Item: If you haven't already referenced your life-cycle analysis,
use APA.
See
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3. Housekeeping Items
For those of you in Section 2, today is the Urban Issues Film Fest, starting at 3:30 in Building 355, Room 203, with Jim Green, Downtown East Side activist from Vancouver. Films will follow, along with free food, in Building 356, Room 109, around 5:00 or 5:30. We can always use volunteers so show up at 4:45 and help if you can!
The life cycle analyses are due today.
Read the rest of the notes on Chapter16 (Conventional Energy Alternatives) on your own. Today, we will cover Chapter 17. In Section 2, I will show a video next Wednesday that is relevant to waste issues, but because of the holiday I won't be able to show it on Thursday.

4. Harnessing tidal energy at the Bay of Fundy
“Not only will atomic power be released, but someday we will harness the rise and fall of the tides and imprison the rays of the sun.”
– Thomas A. Edison, 1921
The Bay of Fundy has the largest vertical difference between high and low tide in the world
One of three tidal power plants in the world
Nova Scotia Power is working on in-stream tidal power technologies for 2010 that would eliminate the need for a dam or sluice
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5. “New” renewable energy sources
“New” renewables are a group of alternative energy sources that include
Energy from the Sun, wind, geothermal heat, and movement of the ocean water
They are commonly referred to as “new” because:
They are not yet used on a wide scale
Their technologies are still in a rapid phase of development
They will play a much larger role in our energy use in the future

6. The “new” renewables currently provide little of our power
FIGURE 17.1
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7. The new renewables are growing quickly
Solar power has grown by 28% each year
Wind power has grown by 48% each year
FIGURE 17.2

8. A switch to renewable energy should increase employment
FIGURE 17.3
Manufacturing, installing, and servicing renewable energy is more labour-intensive than for fossil fuel
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9. Our transition must begin soon
FIGURE 17.4
Federal funding for energy research and development has plummeted in Canada over the past 20 years

10. Solar energy
Passive solar energy = the most common way to harness solar energy
Buildings are designed to maximize direct absorption of sunlight in winter and keep cool in summer
Active solar energy collection = uses technology to focus, move, or store solar energy
Solar energy has been used for hundreds of years

11. Passive solar heating is simple and effective
Low south-facing windows maximize heat in the winter
Overhangs on windows block light from above in the summer
Thermal mass = construction materials that absorb, store, and release heat
Planting vegetation in strategic locations
By heating buildings in winter and cooling them in summer, passive solar methods conserve energy and reduce costs
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12. Active solar energy collection can heat air and water in buildings
Flat plate solar collectors (solar panels) = one active method for harnessing solar energy
Water, air, or antifreeze pass through the collectors, transferring heat throughout the building
Heated water is stored and used later
FIGURE 17.5
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13. Concentrating solar rays magnifies energy
FIGURE 17.6
Power tower = mirrors concentrate sunlight onto receivers to create electricity
Solar-trough collection systems = mirrors focus sunlight on oil in troughs
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14. Photovoltaic cells generate electricity directly
Photovoltaic cells = collect sunlight and convert it into electrical energy
These are used with wind turbines and diesel engines
Photovoltaic (photoelectric) effect = occurs when light strikes one of a pair of metal plates in a PV cell, causing the release of electrons, creating an electric current
A PV cell has two silicon plates, the n-type layer (rich in electrons) and the p-type layer (electron poor)‏
Sunlight causes electrons to flow from the n-type to the p-type layer, generating electricity
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15. A typical photovoltaic cell
FIGURE 17.7
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16. Solar power is little used but fast growing
Solar energy was pushed to the sidelines as fossil fuels dominated our economy
Solar energy use has grown by 28% worldwide
Canada lags behind solar energy use in Germany, Japan and elsewhere
Attractive in developing countries
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17. Global production of PV cells grew sixfold
FIGURE 17.8
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18. Solar power offers many benefits
The Sun will burn for billion more years
Solar technologies are quiet, safe, use no fuels, contain no moving parts, and require little maintenance
They allow local, decentralized control over power
Developing nations can use solar cookers, instead of gathering firewood
Net metering = PV owners can sell excess electricity to their local power utility
New jobs are being created
Solar power does not emit greenhouse gases and air pollution
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19. Location and cost can be drawbacks
The yearly average of Canada’s populated areas exceeds that in both Germany and Japan
FIGURE 17.9
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20. Wind has long been used for energy
Wind turbines = devices that harness power from wind
Windmills have been used for 800 years to pump water to drain wetlands and irrigate crops and to grind grain into flour
The largest wind power producer in Canada is the Le Nordais project in the Gaspé Peninsula
Today, wind power produces electricity for nearly the same price as conventional sources
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21. Modern wind turbines convert kinetic energy to electrical energy
Higher is better to minimize turbulence and maximize wind speed
Turbines rotate in response to wind direction
Doubled wind velocity results in an eight-fold increase in power output
FIGURE 17.10
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22. Wind is the fastest-growing energy sector
Wind power grew 26% per year globally between and 2005
Only a very small portion of this resource is currently being tapped
In Canada, wind power could meet 15% of the nation’s electrical needs
Denmark is the leading manufacturer of wind turbines and derives 20% of its electricity from that source.
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23. Offshore and high-elevation sites can be promising
FIGURE 17.12
Wind speeds are 20% greater over water than over land
There is less air turbulence over water than land
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24. Wind power has many benefits
Wind produces no emissions once installed
It prevents the release of CO2
It is more efficient than conventional power sources
Turbines also use less water than conventional power plants
Farmers and ranchers can lease their land
Produces extra revenue
Landowners can still use their land for other uses
Advancing technology is also driving down the cost of wind farm construction
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25. Wind power has some downsides – but not many
We have no control over when wind will occur
Companies have to invest a lot of research before building a costly wind farm
Good wind sources are not always near population centres that need energy
When wind farms are proposed near population centers, local residents often oppose them
Wind turbines also pose a threat to birds and bats, which can be killed when they fly into rotating blades
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26. weighing the issues
Wind and NIMBY
If you could choose to get your electricity from either a wind farm or a coal-fired power plant, which would you choose?
How would you react if the electric utility proposed to build the wind farm such that the turbines would be clearly visible from your living room window?
Would you support or oppose the development? Why?
If you would oppose it, where would you suggest the farm be located? Do you think anyone might oppose it in that location?
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27. Geothermal energy
FIGURE 17.15
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28. Geothermal energy
Renewable energy is generated from deep within the Earth
Radioactive decay of elements under extremely high pressures deep inside the planet generates heat
This heat rises through magma, fissures, and cracks
Geothermal power plants use heated water and steam for direct heating and generating electricity
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29. Geothermal energy is renewable in principle
But if a geothermal plant uses heated water faster than groundwater is recharged, the plant will run out of water
Operators have begun injecting municipal wastewater into the ground to replenish the supply
Patterns of geothermal activity shift naturally
An area that produces hot groundwater now may not always do so
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30. We can harness geothermal energy for heating and electricity
Geothermal ground source heat pumps (GSHPs) use thermal energy from near-surface sources of earth and water
The pumps heat buildings in the winter by transferring heat from the ground into buildings
In the summer, heat is transferred through underground pipes from the building into the ground
Highly efficient, because heat is simply moved
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31. Use of geothermal power is growing
Currently, geothermal energy provides less than 0.5% of the total energy used worldwide
It provides more power than solar and wind combined
But much less than hydropower and biomass
Commercially viable only in British Columbia
In the right setting, geothermal power can be among the cheapest electricity to generate
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32. Geothermal power has benefits and limitations
Reduces emissions
It does emit very small amounts of gases
Limitations:
May not be sustainable, as CO2 can be released
Water is laced with salts and minerals that corrode equipment and pollute the air
Limited to areas where the energy can be trapped
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33. Ocean Energy: We can harness energy from tides, waves and currents
The rising and falling of ocean tides twice each day throughout the world moves large amounts of water
Differences in height between low and high tides are especially great in long narrow bays
These areas are best for harnessing tidal energy by erecting dams across the outlets of tidal basins
See CBC clip: tion/topics/ /
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34. Energy can be extracted from tidal movement
FIGURE 17.16
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35. Wave energy
Can be developed at a greater variety of sites than tidal energy
The motion of wind- driven waves at the ocean’s surface is harnessed and converted from mechanical energy into electricity
Offshore or coastal
FIGURE 17.17
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36. Ocean currents
Harnesses marine kinetic energy by using the motion of ocean currents, such as the Gulf Stream
Underwater wind turbines have been erected in European waters to test this idea
Source: Google
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37. The ocean stores thermal energy
Each day, the tropical oceans absorb an amount of solar radiation equal to the heat content of 250 billion barrels of oil
The ocean’s surface is warmer than deep water
Ocean thermal energy conversion (OTEC) is based on this gradient in temperature
Closed cycle approach = warm surface water evaporates chemicals, which spin turbines
Open cycle approach = warm surface water is evaporated in a vacuum and its steam turns turbines
Costs remain high and no facility is commercially operational
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38. Hydrogen
The development of fuel cells and hydrogen fuel shows promise to store energy in considerable quantities
To produce clean, efficient electricity
A hydrogen economy would provide a clean, safe, and efficient energy system
2004: Hydrogen Village (H2V) launched in the Greater Toronto Area
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39. A typical hydrogen fuel cell
FIGURE 17.18
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40. A hydrogen-fueled bus
FIGURE 17.19
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41. Hydrogen fuel may be produced from water or other matter
Electrolysis = electricity is input to split hydrogen atoms from the oxygen atoms of water molecules
2H2O  2H2 + O2
Produces pure hydrogen
Will cause some pollution depending on the source of electricity, but less than than other processes
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42. Other ways of obtaining hydrogen
Hydrogen can also be obtained from biomass and fossil fuels, such as methane (CH4)‏
CH4 + 2H2O  4H2 + CO2
Results in emissions of carbon-based pollution
Leakage of hydrogen could deplete stratospheric ozone
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43. Precaution over Hydrogen?
weighing the issues
Precaution over Hydrogen?
Some have recently warned about replacing fossil fuels with hydrogen fuel. An increase in hydrogen gas would deplete hydroxyl (OH) radicals, they hypothesize, possibly leading to ozone depletion and global warming.
Do you think we should apply the precautionary principle to the development of hydrogen fuel and fuel cells?
Or should we embark on pursuing a hydrogen economy before knowing all the scientific answers?
What factors inform your view?
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44. Fuel cells produce electricity
Once isolated, hydrogen gas can be used as a fuel to produce electricity within fuel cells
The chemical reaction involved in that fuel cell is the reverse of electrolysis
2H2 + O2  2H2O
The movement of the hydrogen’s electrons from one electrode to the other creates electricity
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45. Hydrogen and fuel cells have many benefits
We will never run out; hydrogen is the most abundant element in the universe
Can be clean and nontoxic to use
May produce few greenhouse gases and other pollutants
Can be no more dangerous than gasoline in tanks
Cells are energy efficient
Fuel cells are silent and nonpolluting and won’t need to be recharged
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46. Conclusion
Many people are convinced that we need to shift to renewable energy
Renewable sources include solar, wind, geothermal, and ocean energy sources and hydrogen fuel
Renewable energy sources have been held back by inadequate funding and by artificially cheap prices for nonrenewable resources
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47. QUESTION: Review Which of these is not a passive solar technique?
The use of thermal mass
Using flat-plate solar collectors
Installing low, south-facing windows that will maximize sunlight capture in the winter
Using strategically planted vegetation
Answer: b
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48. QUESTION: Review
We can harness power from wind by using devices called:
Wind turbines
Wind parks
Wind farms
Solar cells     
Answer: a
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49. QUESTION: Review
Turbines can be erected singly, but they are most often erected in groups called:
Wind turbines
Wind farms
Wind mills
Solar cells     
        
Answer: b
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50. QUESTION: Review
Which energy source may not be renewable, and is laced with minerals that corrode equipment?
a) Solar panels
b) Wind energy
c) Geothermal energy
d) Hydrogen fuel cells
Answer: c
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51. QUESTION: Interpreting Graphs and Data
What conclusions can you draw from this graph?
Production of PV cells grew rapidly and price fell rapidly
Production of PV cells fell rapidly and price fell rapidly
Production of PV cells grew rapidly and price grew rapidly
Production of PV cells fell rapidly and price grew rapidly
Answer: a
FIGURE 17.8
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