Introduction to Grid-Connected Photovoltaic

1

• Introduction to Grid-Connected Photovoltaic
• It doesnt work if its not in the Sun

2
The Shade Monster

• You CANNOT Accurately Guess When or How Much!
• Theres the Long Way
• Sticks, Levels, Tape Measures, Trigonometry,
  Charts, Calculators . . .
• Theres the Less Long Way
• Solar Pathfinder
• www.solarpathfinder.com

3
Shading Basics

• Shade is not a friend of PV
• Unless it is a ZERO shade application, you cannot
  begin to guess how bad it is!
• The Surprise goes both ways!
• Generally Accepted Principles
• - Zero Shade from 900 AM to 300 PM
• All Times are Solar Times
• Time of year relationship
• - Shorter Days Longer Shadows
• - Lower Production impact if winter shading

4
PV ShadeThe RealityWe dont get perfect
sites too often

• Urban Areas
• Trees
• Adjacent Buildings
• Self-Shade Ridgelines, Roof Obstructions,
  etc.
• Rural Areas
• Trees around Houses
• Generally more potential for Ground-Mount
• Beware of Self-Shading Array Designs!
• No Conclusive Data Available
• We can determine the lost sunlight by hour,
  day, month, and year Not kWH!

5
Acceptable Shade?

• Highest production months from April-September
• No Shade during Peak Hours then is preferred!
• Winter Shading
• Higher Percentage of a Lower Energy Value
• Annual lost sunlight recommendation
• No point of the Array should be installed where
  there is gt 10 loss

6
Solar Pathfinder
7
Declination Offset
Daily Avalailable Energy
Solar Time of Day
Months
Solar Pathfinder Sun Chart for 37-43 N Latitude
8
Shade Sources Times
9
Shade Sources Times
10
Unshaded Times
11
West Side of Home with PV on the East Side. Note
Trees Chimney AM Shade when System should be
peaking!
12
Winter Shading Especially PM!