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Chapter 13 Study Guide
Achieving Energy Sustainability
Readings & Due Dates
Pages 343 – 372
13
3/31/2014
Key Terms:
Biomass
Net removal
Photovoltaic solar cell
Renewable
Biofuels
Geothermal energy
Energy conservation
Ethanol
Ground source heat
pumps
Tiered rate
Biodiesel
Wind energy
Energy efficiency
Flex-fuel vehicles
Wind turbine
Peak Demand
Hydroelectricity
Fuel cell
Passive solar energy
Run-of-the-river
Electrolysis
Thermal Inertia
Water impoundment
Smart grid
Modern carbon
Tidal energy
Carbon neutral
Fossil carbon
Siltation
Active solar energy
1. Choose one renewable energy resource from table 13.1 on page 368 and
answer the following questions:
a. How does this technology work?
b. How could this energy source be used?
c. What are some examples of its current use?
d. What are apparent environmental impacts associated with this resource?
e. Are there hidden environmental and social costs?
f. Is the technology widely accepted today? Why or why not?
g. Do the costs of this technology make it prohibitive for common use? Why
or why not?
2. Opening Story on pg 343: How is the moon producing clean, renewable energy?
Moons gravitational pull causes tides to rise and fall. The kinetic energy of the
moving water can be converted into electricity similar to windmills. Little
environmental impact.
3. What are some common kinds of nondepletable, potentially renewable, and
nonrenewable energy resources? Nondepletable: Wind, Solar, Hydroelectric,
Geothermal; Potentially renewable: Wood & biofuel; Nonrenewable: Nat. gas,
oil, coal, nuclear
4. How do you know if an energy resource is nondepletable, potentially renewable,
or nonrenewable? Nonrenewable can be depleted (run out); nondepletable
cannot be depleted; potentially renewable as long as we use them before they
can be replenished.
5. How does passive solar design and thermal inertia work together to conserve
energy? During the winter, low solar angle can shine directly into a window onto
a floor with high thermal inertia (tile, concrete) and heat the house long after the
sun has set. Likewise in the summer materials with high thermal inertia that are
not heated by the sun due to large overhangs, can stay cool well into the day.
6. What is peak demand, and how does it relate to energy conservation? Peak
demand is greatest quantity of energy used at one time. In energy conservation,
it is important to reduce the peak demand. Variable price structure when
consumers pay less money to use energy at off peak times.
7. What are the major forms of biomass energy? Modern carbon: wood, charcoal,
manure. Liquid biofuels are ethanol (alcohol from plants) and biodiesel.
8. Why is it important to find abundant sources of biomass sources? So that it can
be sustainable and therefore renewable. What are the advantages and
disadvantages of different forms of biomass energy? Advantages: Considered
carbon-neutral; eliminates waste from the environment; available worldwide,
minimal technology. Disadvantages: deforestation, erosion, air pollution, release
carbon into atmosphere
9. What are the types of hydroelectricity generation systems? Run-of-the-river
system (does not store water in a reservoir) and water impoundment system
(most common and can control electric generation by controlling water)
10. How can water be a renewable energy resource? Moving water contains kinetic
energy and as long as there is water flowing, energy can be generated.
11. In what ways do humans capture solar energy for their use? Passive solar
heating and active solar heating which includes solar water heating systems,
concentrated solar thermal electricity systems, and photovoltaic systems
12. How do active and passive solar systems work? What are the advantages of
each? Passive solar energy comes directly from solar radiation without any
intermediate pumps or technology to convert into energy (i.e. solar ovens),
whereas active solar heating uses technology to capture the energy.
13. What is geothermal energy and what is its source? Geothermal energy
generates energy from the Earth’s internal heat. The source of that heat is
natural radioactive decay deep within the Earth’s interior.
14. How is wind used to generate electricity? Kinetic energy from wind is harnessed
by turbines which in turn generate electricity
15. What are the most practical and feasible locations for wind farms? Windy areas
such as mountain passes and offshore areas. Wind farms are usually located
away from buildings and population centers. One necessity of wind farms is
nearness to electrical transmission lines
16. How does a fuel cell work? Operates much like a battery except the reactants
are added continually so the cell works as long as it has fuel. Electricity is
generated by the reaction of hydrogen with oxygen. The protons are forced to go
one direction through a membrane and the electrons are forced to go another
pathway, generating electricity.
17. How do we obtain hydrogen for use in fuel cells? By separating from compounds
by using heat or electricity (like electrolysis in water)
18. Why is hydrogen useful as an alternative to fossil fuels? Hydrogen can act as an
energy carrier and can be stored until needed. If the energy used to generate
the hydrogen in renewable, hydrogen could be a sustainable clean energy
source.
19. What are the barriers to increasing our use of renewable energy sources? New
technology for new energy sources must be invented before we run out of our
current energy resources. Upgrade existing energy infrastructure ($$$) in
addition to investing in new energy sources is very expensive. Relying on
intermittent renewable energy sources such as solar and wind could lead to
instability of the electrical grid.
20. Science Applied (pg 376): Should Corn Become a Fuel?
a. Does ethanol reduce air pollution? It is oxygenated and therefore does
not produce as much CO as gasoline but it does evaporate quicker and
can produce photochemical smog just like CO in car emissions
b. Does ethanol reduce greenhouse gas emissions? Should be carbon
neutral because the carbon used to produce the plants is removed from
the atmosphere cancels each other out. Problem comes when you
account for all the energy used to produce the ethanol and grow the corn,
which ends in a net transfer of carbon to atmosphere. SO NO IT DOES
NOT AT THIS TIME
c. Does ethanol reduce our dependence on gasoline? There is a positive
energy return when using ethanol vs gasoline and therefore lessen our
use of gasoline. But in order to produce ethanol we need more coal and
thus produced CO2. To reduce our dependence by using ethanol, there
would not be enough cropland to supply the US with the ethanol needed
to replace gasoline. Clearly not a practical solution.
d. Are there alternatives to corn ethanol? Cellulosic ethanol produced from
grasses (cellulose which makes up the cell wall of the plant). This
ethanol is more expensive to produce than corn ethanol. Algae may be a
more attractive material because it does not use land.