Energy Emergency and New Materials

1
Energy Emergency and New Materials

• Lei Zhang Yanli Ding

2
Energy Use
Household Energy Consumption
Energy Consumption by sector and region
Source US Energy Information Adminastration
3
US Energy Consumption 2008
Source US Energy Information Adminastration,
2008
4
China Energy Consumption 2008
Coal production ramp up from 645.9 million tons
of oil equivalent in 1999 to 1.552 billion tons
in 2009 but the country was still forced to
increase coal imports by 42 in order to meet
demand China Daily
Source US Energy Information Adminastration,
2008
5
Fossil Fuel Consumption Climbing
Source solarnavigator.net
6
Expanding Population
7
The Hidden Cost of Fossil Fuels
According to US Energy Information
Adminastration(EIA), Energy consumption grows by
53 percent from 2008 to 2035
Oil prices rose in 2010 as a result of growing
demand associated with signs of economic recovery
and a lack of a sufficient supply response.
8
Greenhouse
Source US Energy Information Adminastration
9
More than CO2..

• Air pollutant effects
• Particulates
• PM10 particles particles of 10 micrometers or
  less, cause heart disease, lung cancer, asthma,
  and respiratory infections.
• Sulfur Dioxide
• Nitrogen Oxides
• Ozone

10
The Hidden Cost of Fossil Fuels Pollutants

• Particulates
• Sulfur Dioxide acid rain damage ecosystems,
  historical buildings and materials (corrosion)
• Nitrogen Oxides
• Ozone

11
Outdoor air pollution kills 1.3 million each year
Source World Health Organization(2010)
12
Mapping air pollution using corn grown in US
fields
Source Geophysical Research Letters.(2007)
13
Renewable Energy
Geothermal
Solar
Nuclear Fission
Hydroelectric
Wind
Rhett Allain,Southeastern Louisiana University
14
Solar Energy

• Energy produced by the sun
• Clean, renewable source of energy
• Harnessed by solar collection methods such as
  solar cells
• Converted into usable energy such as electricity
• Consumes no fuel
• Wide power-handling capabilities
• High power-to-weight ratio
• It's time to go solar!

15
(No Transcript)
16
Energy from the Sun is Abundant
Source http//www.ez2c.de/ml/solar_land_area/
17

• kdlai

18
(No Transcript)
19
Solar cells would need to cover an area
comparable to the size of Texas to meet US energy
demand today
20
How does solar cell work?

• It's time to go solar!

21
Solar Energy Spectrum
Power reaching earth 1.37 KW/m2
22
Absorption of Light

• Electrons can jump between bands
• Incident light with energy than the band gap
  energy can be used to excite the electrons

http//www.3dchem.com/molecules.asp?ID135
23
(No Transcript)
24
Crystalline Silicon

• monocrystalline silicon (c-Si)
• polycrystalline silicon, or multicrystalline
  silicon, (poly-Si or mc-Si)
• ribbon silicon

Polycrystalline silicon wafer
25

• Light with energy greater than the band gap
  energy of Si is absorbed
• Energy is given to an electron in the crystal
  lattice
• The energy excites the electron it is free to
  move
• A positive hole is left in the electrons
  place
• This separation of electrons and holes creates a
  voltage and a current

Source http//nanosense.org/activities/cleanenerg
y/solarcellanimation.html
26

• Expensive
• Made in high vacuum at high heat
• High manufacturing costs
• Need TLC
• Fragile, rigid, thick
• Long return on investment
• Takes 4 years to produce energy savings
  equivalent to cost of production

27
Thin Films

• Produced from cheaper polycrystalline materials
  and glass
• High optical absorption coefficients
• Bandgap suited to solar spectrum

28
CdTe/CdS Solar Cell

• CdTe Bandgap 1.5 eV Absorption coefficient 10
  times that of Si
• CdS Bandgap 2.5 eV Acts as window layer
• Limitation Poor contact quality with p-CdTe (
  0.1 Wcm2)

29
Dye-Sensitized Solar Cells

• Light with high enough energy excites electrons
  in dye molecules
• Excited electrons infused into semiconducting
  TiO2, transported out of cell
• Positive holes left in dye molecules
• Separation of excited electrons and holes
  creates a voltage

Source http//nanosense.org/activities/cleanenerg
y/solarcellanimation.html
30

• Relatively inexpensive
• Made in non-vacuum setting mainly at room
  temperature
• Relatively simple manufacturing process
• Need little TLC
• Thin, lightweight, flexible
• Short return on investment
• Takes approx 3 months to produce energy savings
  equivalent to cost of production