Texas Solar Power Company

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Texas Solar Power Company
Austin, Texas
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Solar Power 101

• Why use Solar
• How electricity is generated
• How energy is used
• Types of solar systems
• What it costs
• Q A

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Why Solar?

• You care about the future
• Sources of fossil fuel are finite
• Decreasing CO2 leads to climate stabablization
• You want to grow your own energy
• and.

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Solar Energy is the most abundant renewable
energy in the world.
Photo Light Voltaic Electricity
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Thomas Edison to Henry Ford, 1931
Id put my money on the sun and solar energy.
What a source of power! I hope we dont have to
wait until oil and coal run out before we tackle
that.
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Some Interesting Stats

• Average residential system taking 1
  car off the road (reduction of greenhouse
  gas emissions)

• The earth receives more energy from the sun in
  just one hour than the world uses in a whole
  year.

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Solar Systems work well

• No moving parts
• No emissions
• No water required
  
• (except, perhaps,
• periodic cleaning)
• Grid-tie systems
• are easily managed
• putting power
• directly on the grid.

Some assembly required! Batteries not
included.
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Austin is a great place for Solar!
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What are Solar Cells?

• Thin wafers of silicon
• Similar to computer chips
• Much bigger
• Much cheaper!
• Silicon is abundant (sand)
• Non-toxic, safe

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PHYSICS
How to Make Electricity

• Silicone absorbs white sunlight
• Causes electrons in atoms to collide with
  each other
• Activity creates and - charges
• Charges collect on to and - solders that lead
  to conducts

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What are Solar Modules?

• Modules or panels are made up of multiple cells.
• Two kinds of PV modules
• Monocrystalline whole wafers
• Polycrystalline composite wafers

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What are Solar Arrays?

• PV or Solar Arrays are made of a series of
  connected modules.

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3 Basic Systems

• Grid-tie
• Grid-tie / battery backup
• Stand alone or off-grid

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Grid - Tie

• Net Metering monitors the flow of power both TO
  and FROM the utility grid
• Grid-Tie feeds power into the main load center
• Grid-Tie systems allow customers to continue to
  receive power from the grid, while pushing any
  excess power from the PV system to the grid

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Net Metering

• Electric meter can run both forwards and
  backwards
• Required of all electricity providers
• If you come out ahead, the energy company is not
  required to pay you at certain rate
• Austin Energy pays wholesale rate

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Stand Alone or Off - Grid

• Designed to meet all power needs
• Necessary when location is not served by power
  company
• Design constraints
• Surge Amps
• Battery bank amp hour capacity
• Days of back-up storage (poor sunlight)
• Square footage for components
• We use a lot of electricity!

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Grid Tie, Battery Back-Up

• In case of grid failure, system provides
  uninterrupted power to specified loads
• Battery bank is designed to meet users load
  objective in terms of
• Amps
• Run Time

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Grid Tie, Battery Back-Up

• Additional components used by this system
• Grid-tie Battery back-up Inverter
• Charge Controllers
• Batteries
• Inverters have both outputs and inputs
• OUTPUTS are from Batteries or PV array
• INPUTS are from the load center (grid)
• Charge batteries
• Monitor voltage

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Example of a residential systems battery bank
with 14 hours of reserve power.
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Majority of Installations Grid-Tie
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Ideal Location for a Solar Install

• South facing roof
• Tilted to locations latitude.
• Austin 30.27
• to a 7 / 12 pitch
• Shade-free area, every day of the year

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Ideal Location for a Solar Install

• We can provide the tilt

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Components of a Solar Installation

• PV Modules produces Direct Current (DC)
• We use Alternating Current (AC)
• Power must be converted from DC to AC with an
  Inverter

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A Grid Tie System
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System Specs

• 1 kW 100 Sq. Ft
• 3 - 7 lbs per Sq. Ft.
• Need minimum load center 125A (for a 3kW PV
  System)
• 4 x 3 space for electrical equipment

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Example of typical US household power use
Where Does all the Power Go?
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How Much Power Can You Produce?

• Austin Energy offers a fabulous rebate program
  3.75 per watt
• AE caps _at_ 50K
• A 14 kilowatt system maxes out their per-year
  allotment for a residential installation
• One rebate per year, per system.
• The following calculations are based on a 3kW
  system

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How Much Power Can You Produce?

• 3,000 Watts 3kW
• System will produce 3000 watts per hour
• Austin averages 5.4 good sun hours per day (3000
  x 5.4 hours 16,200 watt hours per day)
• 16,200 x 30.5 days/mo. 494 kW/mo.

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How Much Power Can You Produce?

• One more factor.
• The DC power produced from the system must be
  converted to AC power
• This process looses power, so derating factor
  of .77 must be calculated
• 494,000 W/mo. x .77 380kWh/mo.
• On average, this is 380 kWh per month

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How Much Will That Cost?
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Whats the Payback?
NOTE Solar locks in operational costs and
hedges against rising energy costs. As the price
of energy goes up, savings increase
exponentially.
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Take Home

• Accumulated Savings after 25 years 18,650
• Payback Period 8
• Average Rate of Return 8

Caveats

• Assumption is made that utility rates will
  increase 5 each year.
• Cash Flow based on comparing the solar investment
  to a similar 25 year bond assuming a 15 capital
  gain obligation
• Final Cost based on Total Cost less Austin Energy
  Rebate and Federal Incentive

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Many variations
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Many variations
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Solar Hot Wateraka Solar Thermal

• Proven technology
• GREAT use of suns power more efficient than
  PV
• Can provide 85-90 home hot water needs
• Self-automated. Low-to-no maintenance

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How it Works

• Turns on/off daily
• H2O heated by sun stored in tank
• Back-up used when no sun
• Hot water 24/7

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SHW System Specs

• 64 square feet
• Weight 200 pounds
• Minimum 15 degree tilt
• South, SE, or SW orientation
• Ideally, shade-free