The Value of West Facing Solar Panels

Its almost 2 years since I installed a solar power system on my current house.

The installation is 8 x 250 watt panels facing North and these 5 x 250 watt panels facing West.

Over the time they have been installed the amount generated has been:

  • North Facing panels – 5,164 kw
  • West Facing panels – 2,882 kw
  • Overall generation – 8,046 kw

Power production for each panel works out at:

  • 648 kw for North facing panels
  • 576 kw for west facing panels (89% of north facing panel’s production)

At first sight this seems to indicate that the North Panels are better value. . . . but there are a couple of reasons why this really isn’t the case.

  1. When we are using electricity
  2. Feed In Tariff (FIT)  at 11.8 cents/kw is less than the tariff for taking power from the grid of 25cents/kw.

Time of Use

Generally we are mainly out during the day so apart from some use in the morning (before the solar system is generating power) our main actual use is from late afternoon.

The main use during the day is just the refrigerators and an hour or so of washing machine use 3-4 times a week.

We are home most evening; running air conditioning/heating, cooking meals and watching TV

Effect of Tariffs

Most of the power generated by the north facing panels will be going into the grid and only getting us 11.8 cents. . . . say 30% saving power and 70% going to the grid at 25 cents/kw.

So for each North facing panel the value of the power  = 648 x 25 x 0.3 + 648 x 11.8 x 0.7 =  $102.1.

With the West facing panel power its going to be more power being saved than going to the grid  . . . . say 50% saving power and 50% going to the grid

So for each West facing panel the value of the power = 576 x 25 x 0.5 + 576 x 11.8 x 0.5  =  $106.0 . . . . .MORE THAN THE NORTH FACING PANELS!!!