Achieving Energy Sustainably

1
Achieving Energy Sustainably

• Chapter 13

2
Renewable Energy

• Nonrenewable Refresher
• a. petroleum, natural gas, coal, and uranium
• Renewable Energy
• a. biomass potentially renewable
• b. solar, wind, geothermal,
• hydroelectric, and tidal
• - nondepletable

http//bcs.whfreeman.com/friedlandapes/668210__69
0868__
3

• Facts about Renewable Energy
• a. 13 of energy used worldwide
• b. biomass most widely used today
• c. 7 of energy use in US (biomass and
  hydroelectricity)
• d. more sustainable than nonrenewable, but
  still has
• environmental impacts

4
Using Energy Less

• Energy Conservation and Efficiency
• a. conservation ways to use the source less
• 1. locally
• - turning down thermostat when out of
  house
• - turning off lights when not in the
  room
• 2. government
• - taxing electricity, oil, and natural
  gas
• - offer rebates or tax credits
• 3. can increase efficiency by conserving
• - get the same amount of work from
  using less
• energy

5

• b. sustainable design
• 1. passive solar heating
• - solar radiation maintaining building
• temperatures
• - carefully placed windows (heating and
  lighting)
• - dark-colored roofs v. light-colored
  roofs
• 2. green roofs
• 3. recycled denim insulation in walls and
  ceilings

http//science.howstuffworks.com/environmental/gre
en-science/green-rooftop.htm
6
Biomass

• Fuel Types
• a. wood, charcoal, animal wastes, plant
  remains,
• and municipal solid waste (MSW)
• b. ethanol and biodiesel (biofuels)
• United States
• a. 2/3 wood
• b. 1/3 MSW and biofuels

7

• Solid Biomass
• a. wood
• 1. heating, pulp and paper industries,
  power plants
• 2. sustainable if forest growth is able to
  keep up
• b. charcoal
• 1. contains more energy than wood
• 2. produces less smoke
• c. manure
• 1. indoor heating and cooking
• 2. reduces risk of disease transmission,
  but does give
• off pollutants causing respiratory
  illnesses

8

• Biofuels
• a. ethanol
• 1. derived from mostly corn products
• 2. sugarcane, wood chips, crop waste, or
  switchgrass
• 3. US world leader in production of
  ethanol, Brazil
• second
• 4. Gasohol
• - ethanol mixed with gasoline
• - produces less air pollutants
• - reduces gas mileage

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• b. biodiesel
• 1. derived from soybean oil or processed
• vegetable oil
• 2. typically diluted to B-20
• 3. lower emissions of CO compared to
• petroleum diesel

http//bionews-tx.com/news/2013/05/27/benefuel-fli
nt-hill-resources-to-develop-us-biodiesel-projects
/
10
Hydroelectricity

• Hydroelectricity electricity generated by the
  kinetic energy
• of moving
  water
• 2nd most common form of renewable energy in U.S.
  and world
• Most widely used for electricity generation
• China worlds leading producer, followed by
  Brazil and U.S.
• Water-impoundment, run-of-the-river, and tidal
  energy

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• Amount of electricity depends on 2 factors
• a. flow rate
• 1. amount of water that flows paste a
  certain point
• per unit time
• 2. higher the flow rate more KE, more
  electricity
• b. vertical distance water falls
• 1. greater the distance more PE water
  has, more
• electricity

12

• Approaches of Hydroelectricity
• a. run-of-the-river
• 1. water retained behind low dam, runs
  through channel
• 2. advantages
• - little flooding upstream
• - seasonal changes in river flow
  not interrupted
• 3. disadvantages
• - small
• - intermittent electricity
  generation
• - no electricity generated when
  hot and dry

13

• b. water impoundment systems
• 1. water stored in reservoir behind
  dam
• 2. most common method
• 3. largest in U.S. Grand Coulee Dam
  in Washington
• State
• 4. largest in world Three Gorges Dam
  in China

14

• c. tidal systems
• - movement of water driven by the
  gravitational pull
• of the moon
• - use gates and turbines to capture KE of
  moving
• water flowing through estuaries,
  rivers, etc
• - can be disruptive to coastlines

15

• Sustainable Practice?
• a. expensive to build, but minimal fossil
  fuel once built
• b. no air pollution, waste, or CO2
• c. reservoir provide recreational
  opportunities
• d. environmental impacts
• 1. force people to relocate
• 2. disrupt a free-flowing river
• 3. reservoirs contain less oxygen than
  free-flowing

16
Solar Energy

• Passive Solar Heating
• a. solar ovens
• b. carefully placed windows, dark v. light-
• colored

17

• Active Solar Energy
• a. captures sunlight with use of technology
• b. solar heating systems
• 1. provides hot water, heating swimming
  pools
• 2. backup is available for cloudy or
  cold days
• c. photovoltaic systems
• 1. capture energy from Sun as light, not
  heat and convert
• directly into energy
• 2. solar panels

18

• d. concentrating solar thermal systems
  (CST)
• 1. use lenses and tracking systems
  to focus the
• sunlight on a large area into a
  small beam
• 2. heat of beam evaporates water,
  produces steam
• that turns turbine to generate
  electricity
• 3. uses lots of land
• 4. cant generate electricity at
  night

19

• Advantages of active solar energy
• a. no air pollution, water pollution or CO2
• b. produces electricity when needed the most
• c. economically feasible
• Drawbacks
• a. solar panels are expensive to manufacture
  and install,
• requires lots of energy and water, and
  involves toxic
• metals and chemicals

20
Geothermal Energy

• Geothermal Energy
• a. heat that comes from natural radioactive
  decay
• of elements deep within the Earth
• b. geyser and springs
• c. direct source of heat, generate
  electricity
• d. United States, China, and Iceland
  largest
• producers

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• e. nondepletable as long as we dont deplete
• the groundwater source
• f. drawback
• 1. hazardous gases emitted from power plant

http//commerce.mt.gov/energy/geothermal.mcpx
22
Wind Energy

• Wind Energy
• a. largest amounts of electricity generated
  by
• wind California and Texas
• b. wind turbine
• 1. converts KE of moving air into
  electricity
• 2. wind parks

http//www.pterra.com/index.php/transient-temporar
y-and-ground-fault-overvoltages-at-wind-farm-insta
llations/
23

• c. advantages
• 1. produces no air pollution, no
  greenhouse
• gases
• 2. wind farms can share land with other
  uses
• d. disadvantages
• 1. rely on batteries
• 2. noise
• 3. appearance
• 4. kill birds and bats

http//sayanythingblog.com/entry/federal-wildlife-
officials-give-their-blessing-to-killing-endangere
d-birds/
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Hydrogen Fuel Cells

• Fuel cell
• a. operates like a battery
• b. produces electricity as long as it is
  supplied
• with fuel
• c. free hydrogen gas
• 1. rare
• 2. explosive
• 3. obtain through electrolysis

http//butane.chem.uiuc.edu/pshapley/Enlist/Labs/F
uelCellLab/FuelCell.html
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• d. alternative energy source?
• 1. 80 efficient creating electricity and
• byproduct is water
• 2. need a safe delivery of hydrogen (could
• explode)
• 3. hydrogen-fueled car can use an electric
• motor

26
Improving Electrical Grid

• Smart Grid
• a. efficient, self-regulating network that
• accepts any source of electricity and
• distributes it
• b. coordinates energy use with energy
• availability