Alternative Energy

1
Chapter 13

• Alternative Energy

2
Alternative Energy

• Hydropower
• Wind
• Solar
• Biomass
• Ocean (waves)
• Geothermal

3
Solar

• Depends on longitude, latitude, season, time of
  day, degree of cloud cover
• More solar energy at lower latitudes during
  summer months, in afternoon, cloudless

4
Types

• Passive- Energy used to heat air or water without
  need for pumps or fans to distribute (e.g. south
  facing windows, deciduous trees, brick/stone
  walls and floors, eaves, orientation)
• Active- series of collection devices used to
  gather solar energy
• solar heating and electric generation

5
Solar Heating

• Water pumped through tubes in solar heat
  collector and used to head buildings, as hot
  water (SRVHS pool heater)

6
Electricity Generation

• Solar thermal electric generation sun rays
  focused on oil-filled pipes and superheated. Hot
  oil used to create superheated steam which turns
  turbines and generates electricity.

7
Photovoltaic (PV) Solar- Cells

• Wafer or thin films of solid state material that
  are treated with metals in such a way that they
  generated a flow of electrons of electricity
• PV cells are only 10-15 efficient in
  converting solar energy to electricity.

8
Solar Hydrogen Generation

• Electricity from solar used to split water into
  oxygen and hydrogen (electrolysis) Hydrogen then
  used in a fuel cell
• Fuel Cell- electrochemical cell similar to a
  battery in which oxygen and hydrogen react to
  form water and energy.

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Hydrogen generation
10
Indirect Solar

• Biomass
• Wind Energy
• Hydropower (hydrologic cycle driven by sun)

11
Biomass

• Chemical energy stored in wood, animal dung,
  peat, ect. Burning it releases energy. Can also
  be converted to liquid fuel (ethanol and
  methanol)
• Biogas- conversion of biomass into a mixture of
  gases that are then used for cooking and lighting
• Major disadvantages- 60-70 efficient in
  conversion to liquid fuel (requires a lot of land
  and water)

12
Wind Energy

• One of the most cost- competitive forms
• Problems include location, time dependent factors
  and birds

13
Hydropower

• Sun drives hydrologic cycle
• Ultimately generates 20 of worlds electricity
• Main problems- affects river flow
• Other problems- river induced seismicity and
  evaporation in arid areas and dam breaks and
  water borne diseases.

14
Hydroelectric

• animation

15
Ocean Waves

• Indirect form of solar energy
• Water into/ out of hollow tubes drive turbines
• Also wave oscillation

16
Ocean Thermal Energy Conversion

• Uses ocean temp gradient and (up to 24 degrees
  Celsius difference ) by using warm ocean water to
  heat ammonia (boiling point 33 degrees Celsius)
  which drives turbines
• Ocean Thermal Energy Conversion (OTEC)

17
Tidal Energy

• Uses change in the tide levels to drive turbines
• Bay of Fundy in Nova Scotia has largest tides in
  the world 53 ft. difference)

18
Geothermal Energy

• Uses natural occurring heat on earth (from
  tectonic plate friction and radioactive decay)
• Geothermal typically exerts as hot steam or water
  used to turn turbines
• Also use geothermal heat pump by exchanging air
  temp with earth

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Geothermal Energy (contd)

• US is the Worlds largest geothermal producer with
  the Geysers in CA being the worlds largest
  geothermal field
• Pros emit fraction of air pollution and minimal
  land use
• Cons hydrogen sulfide is emitted and land stinks

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Energy Solution

• Conservation- moderating or eliminating wasteful
  or unnecessary energy use
• Efficiency- using technology to do a particular
  task with less energy
• Efficiency is measured as a whole by energy
  intensity
• Country total Energy/ gross domestic product
  energy intensity

21
Energy Solution

• Developing Countries typically buy older, less
  efficient technologies (less expensive)
  concerns
• Energy Star- labeling program in US to promote
  development sales and purchasing of energy
  efficient equipment

22
Energy Solution

• National Appliance Energy Conservation Act-
• Set energy efficient standards
• Provides labeling/ guides on efficiency info
• Cogeneration- production of two useful forms of
  energy from same fuel (e.g. burn natural gas to
  create electricity and also creates steam to heat
  buildings- good on small scale)

23
Energy Solution

• Demand-side Mgt.- tiered pricing cash awards/
  rebates, etc. To encourage/ help consumers
  manages their energy use and save
• Green power- power generated from renewable
  resources (not impact free!!!!)
• Deregulation- consumer price driven by marked but
  not controlled by government or quasi-government
  organization