Transcript Alt101KayaVersion

Alternative Energy 101
Yuki Bailey
Vivian Eng
Kristen Lee
Chloe Liu
Chemistry Kaya 2:00
OUR PURPOSE…
Enlightenment on
Solar Power
Hydroelectric Power
Wind Power
Specifics
Myths
How It Works
Pros/Cons
Solar Power Myths
Is Solar energy unlimited? NO!
Sun will exist for a long time, but at any given
place on the Earth’s surface, the amount of
sunlight received is limited.
At night or when it is overcast, there may be no
daylight at all.
The amount of electricity that can be generated
by solar cells is not great compared to the
demand.
Solar energy in quantity, requires huge
installations.
How do we store significant amounts of
electricity when the sun is not available to
produce it?
Unknown
How does it work?
•Photovoltaic cells made out of semiconductors (often silicon)
•Sunlight strikes cell then semi conductor
material absorbs light energy
•Allowing the silicon electrons to flow freely
•PV cells also have at least one electric field
that steers the loose electrons into the same
direction
•Metal surfaces located on the top and
bottom of PV cells convert this current into
usable energy
Pros of Solar Power
• A renewable resource as long as there
is Sun
• No water or air pollution
• Can be used for heating and lighting
• Heat pools, spas, and water tanks
• Low maintenance
Cons of Solar Power
• No Sun: NO ENERGY (nighttime and
cloudy days)
• Solar power stations are $$$
• Can only realistically be used to power
transport vehicles by converting light
energy into another form of stored
energy (battery)
Hydroelectric Power
Myths and Definition
• Comes from the potential energy of dammed
water driving a water turbine and generator
• Clean, no polluting, environmentally friendly:
NOT! Because floods the land and displaces
wildlife
• It is not a renewable energy source if
reservoirs are involved (usually)
How does it work?
Water from reservoir is considered to be
stored energy
Intake water flows into dam as kinetic energy,
turning turbine which is connected to a
generator
The generator takes energy and produces
alternating currents (AC)
The transformer collects the AC and converts
it to stronger voltage currents
Used water comes out back into river
Pros of Hydroelectric Power
• Dams can store water directly from the rivers
• Provides recreational activities such as
fishing, boating, and swimming
• Simple design= inexpensive repairs and low
maintenance cost
• Dams can be shut down instantly if needed
• Very few breakdowns
Cons of Hydroelectric Power
• Requires flooding
• Disrupts natural seasonal changes in the
river, ecosystems can be destroyed
• Silt that usually flows down to the beaches
and estuaries is blocked by the dam
• Plant decay caused by downstream of major
dams produces green house gases
• Expensive to build
• If there is a drought, it becomes useless or
produces less power
Wind Energy
Myths
• Definition: Wind energy propels the blades of
wind turbines = energy (by means of
electrical generator)
• Turbines are noisy: Not! Because noise is =
kitchen refrigerator/ moderately quiet room
• Turbines are ugly: Not! Beauty is in the eyes
of the beholder and careful designing = less
visual concerns
• Turbines harm wildlife: Not! Because wind
energy development’s impact on birds is
extremely low compared with other human
related activities
How does it work?
Similar to hydropower dams, except
using wind kinetic energy to produce
currents
Wind moves turbine blades, turning a
shaft in the hub that is connected to a
generator
Generator changes energy into
electricity
Pros of Wind Energy
Produces no pollution that effects the
environment (no chemical process take
place)
Renewable source= never run out
Farming and grazing can still take place
Can be built off shore
Cons of Wind Energy
Consistent wind is needed for continuous
power generation (wind speed decreases=
turbine lingers and less energy is generated)
Large wind farms can have a negative effect
on scenery
Fact: Today 1.6 million homes are served by
wind energy
Goal:2020 =25 million homes served by wind
power
Energy Costs Comparison
Resource Type
Average Cost (cents per kWh)
Hydroelectric
2-5
Nuc lear
3-4
Coal
4-5
Natural gas
4-5
Wind
4-10
Geothermal
5-8
Biomas s
8-12
Hydrogen fuel cell
10-15
Solar
15-32
Sources: American Wind Energy Association, Wind Blog,
Stanford Schoo l of Earth Scienc es
IN CONCLUSION…
Alternative energy is flawed…but has a
lot of POTENTIAL
Solar Power
= best for personal use
Hydroelectric and Wind Power
=Community use
Bibliography
Solar Power Resources
http://www.pv.unsw.edu.au/images/future-students/solar-cell_p-n.jpg
http://www.howstuffworks.com/solar-cell.htm/
http://www.global-merchants.com/home/solars.htm
http://www.howstuffworks.com/solar-cell7.htm
Hydroelectric Power Resources
http://www1.eere.energy.gov/windandhydro/index.html
http://people.howstuffworks.com/hydropower-plant.htm
http://science.howstuffworks.com/wind-power.htm
Wind Power Resources
http://www.eia.doe.gov/kids/energyfacts/sources/renewable/wind.html
http://www.pacificorp.com/File/File4722.pdf
All Three
http://www.swarthmore.edu/NatSci/sciproject/windpowertalk.html
http://drake.marin.k12.ca.us/stuwork/rockwater/Upload%20this%20doc
--dams%20and%20hydropower%20report/pros%20and%20cons.html
http://egj.lib.uidaho.edu/egi09/youngqu1.html