Good day, sunshine!
Please get out your solar handout from last
class! 
 Please read the board!

Why fossil fuels?
Why NOT Fossil Fuels?

What are the drawbacks of using fossil fuels?
Sustainable energy sources
4 types of Solar power



Photovoltaics
Concentrated tower
systems
Passive and active
heating systems
Photovoltaics
How does it work?


Photovoltaic cells
contain a
semiconductor
material – creates a
flow of electrons
(electricity!) when
hit by light.
Batteries store
electricity for cloudy
days or nights.
Discovery Green down town


Two arrays totaling
256 solar panels
how much is it
generating RIGHT
NOW????
Ikea on I-10


3,388 panels
Completed June 2012



Solar arc in
Japan
5,000 solar
panels
500,000kWh
of electricity
Solar panels are great for remote
locations – free standing systems

Customers don’t need
to be connected to the
grid
Our electric “grid” = power plants
connected to consumers
Solar update!



US solar industry – record growth in 2012,
16,ooo,ooo panels installed in nation, record 76%
growth
Texas is in the top 10 states for solar installation
and has the “most untapped potential” for solar
(still just .1%of electricity)
Module costs have dropped 60% last two years
OTHER KINDS OF SOLAR
POWER




Concentrated solar towers! 2007 near Seville
624 mirror, 35-story tower
Heat turns water to steam for turbines
Power for 6,000 homes
Ivanpah Solar Electric Generating
System – Mojave desert California



5.5 square miles
Power for140,000
homes
Molten salt stores heat
to be released on
demand – even at
night.
How it works




Light bounces off mirrors
and is concentrated at
top of tower.
Molten salt is pumped to
top of tower where light
heats it up
Molten salt is used to
turn water to steam 
turbine  generator 
electricity!
Connected to existing
electric grid.
Mirrors track sun’s movement
Passive solar – heats air or water; no
electricity
•
•
•
In winter when sun is low
in sky, light enters,
bounces, turns into heat
which is trapped by the
super-insulated windows
and walls.
In summer, wide roof
overhang blocks
sunlight, keeping house
cool.
Windows face south and
west.
Hudson Passive Project NY
Villa Nyberg, Sweden
Passivhaus, Germany
Fablab house, Madrid Spain
Crossways, UK
Vogel House, Switzerland
Active systems
Water piping on roof warms water.
(New Hampshire)
Active systems



Water pipes on roof
heat up.
Water brought down
into heat exchanger in
house which warms the
shower water.
Cooled water pumped
back to roof to warm
up.

Can also be used to
heat a house with
radiators.
Active system
th
4

period homework
Tomorrow: building
solar pizza box ovens!
th
th
5 /6


period homework
Three questions for Mr. Morton of Texas Solar
Outfitters.
Listen for the answers during tomorrow’s talk.
Questions and answers turned in at the end of the
period tomorrow for a grade.
Solar giants

Germany! - requires
solar installation on
new buildings; gave
tax rebates for homes
installing photovoltaics.
So what are the trade offs?

Benefits

Disadvantages