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

Can also be used to heat a house with radiators.

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.

Active system

4th period homework

Tomorrow: building solar pizza box ovens!

5th/6th 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