1
What are the characteristics of a sustainable energy source, and what role does renewable energy play in terms of global energy production?
INFOGRAPHIC 23.1
True or False: The use of fossil fuels is projected to decline in the next 50 years as the use of renewable energy sources increases.
FALSE
Which of the following renewable energy sources contributes the largest proportion of energy worldwide?
Wind
Water
Solar
Biomass
D
Which of the following in not a characteristic of sustainable energy sources?
They must be renewable.
We must use them at or less than the rate at which they are replenished.
They must have no environmental impact.
All of these are characteristics of sustainable energy.
C
2
How do wind and solar power technologies capture energy? What are the advantages and disadvantages of wind and solar power, and how does each compare to fossil fuels in terms of true costs?
INFOGRAPHIC 23.2, INFOGRAPHIC 23.3 AND TABLE 23.1
Solar technologies that capture heat without any electronic or mechanical assistance are called:
passive solar technologies.
active solar technologies.
solar thermal systems.
photovoltaic solar cells.
A
Which of the following is not an advantage that solar and wind power share?
Pollution free
Effective at large and small scales
The most inexpensive renewable technologies to install
Job creation
C
Compare and contrast the production of electricity by a wind turbine and the production of electricity by heating water to produce steam (thermoelectric production).
In both cases the ultimate goal is to turn a turbine attached to a generator to produce electricity. With a wind turbine, the wind mechanically rotates the generator. With thermoelectric methods, steam turns the turbine to rotate the generator. The main difference is the production of waste products (emissions from burning a fuel or nuclear waste) from thermoelectric production. Another difference is scale and ease of increasing output on demand - a single coal or nuclear power plant can produce as much electricity as hundreds of wind turbines and their output is more easily increased or decreased to meet demand.
3
In what ways can we harness geothermal energy and the power of water? What are some of the trade-offs associated with each of these resources?
INFOGRAPHIC 23.4, INFOGRAPHIC 23.5 AND TABLE 23.1
True or False: While geothermal power plants need to be built near sources of underground heat such as hot springs, geothermal heat pumps can be installed in any homes built on land.
TRUE
Which disadvantage of large dams can the smaller run-of-the-river dams avoid?
The smaller dams do a better job at flood control.
The environmental damage of creating a reservoir is avoided.
The smaller dams don’t generate air pollution like the large dams do.
Production capacity will be steady not variable, as with large dams.
B
Explain how a geothermal heat pump works and how it can lower both heating and cooling costs for homeowners.
Fluid filled pipes are buried underground and this fluid is pumped through the pipes from the ground to the house and back again. The fluid picks up the 55°F temperature of the ground and delivers this to the home. In the summer this can be used to cool the home (reducing air conditioning bills). In the winter the home only needs to be heated from a starting place of 55°F — requiring that a furnace work much less than if it were heating the house up from the outside temperature, thus lowering heating bills.
How were Native Americans and wild salmon populations adversely affected by the construction of the Grand Coulee Dam? Do you think this dam should have been built? Justify your answer.
The Native Americans lost their homes and ancestral lands — villages, burial grounds and other sacred places were permanently flooded and inaccessible. The salmon were unable to access their spawning streams. Whether the construction of this dam was worth the price depends on how much weight one gives the benefits (electricity to the region; reduced need to burn fossil fuels) and the disadvantages described above.
4
What roles do conservation and energy efficiency play in helping us meet our energy needs sustainably?
INFOGRAPHIC 23.6 AND TABLE 23.2
Energy advisors say “the greenest kilowatt is the one:
produced by solar power.”
that doesn’t harm the Earth.”
that’s cheapest.”
you never use.”
D
12. Which of the following should you do first if you want to lower your electric bill?
Install PV panels on your rooftop
Have an energy audit done to see where your home is most inefficient
Replace your appliances with energy-efficient models
Install more insulation in your attic and exterior walls
B
What is the concept of “payback time,” and how can it be useful in deciding what types of conservation measures to pursue?
Payback time is the time it takes for the energy savings of an energy upgrade to pay for the cost of its purchase and installation. Knowing the payback time of different options allows homeowners to choose the most cost-effective upgrades.
5
What combination of actions did Samsø take to become an energy-positive island? What is the take-home message to other communities that might want to reduce their use of fossil fuels?
INFOGRAPHIC 23.7
Samsø used_____________,_______________, and __________energy sources to meet its energy needs.
Wind, solar, and biomass
As a member of the city council in a small town in New Mexico, you must vote on a new source of energy for your growing community. What should be the first step in determining where the energy will come from?
Rely on historical practices and build a new coal-fired power plant.
Pass a new law that requires all buildings to have solar panels installed.
Conduct an assessment of available energy sources, both renewable and nonrenewable.
Provide citizens a tax subsidy for improving the energy efficiency of their homes.
C
Describe the characteristics of the four sustainable energy sources presented here for generating electricity: wind, solar, geothermal, and hydroelectric power. Why are all sources not practical for every location?
Electricity produced from wind, geothermal, and water all share the common feature of some force turning a turbine which spins adjacent to copper wiring within a generator to generate electricity. Wind energy uses the power of wind to turn turbines (windmills). Geothermal energy uses the heat produced by the Earth to heat water and produce steam which turns a turbine. Water energy uses the energy of water falling downhill and/or running by to turn a turbine. Solar energy is different in that it uses the energy of the sun to displace electrons in a photovoltaic cell which generates electrical current. All sources are not practical for every location because all locations don’t have abundant sunlight, or water, wind, etc. The practicality of these depends on abundance, and abundance varies across the planet.
469