The following factors can all affect the output of your solar array. Note the Clean Energy Councils, averaged daily Solar PV output figures, take all of these important factors into account, before supplying an expected averaged daily output.
The output of any Solar PV System will relate directly to your location as noted in the Clean Energy Councils Daily Averaged Daily Output table.
Shading can have a large effect on the output of your solar array. Output can be greatly reduced when shading occurs. The time of the day the shading occurs is also important, when power is greatly reduced if shading occurs during the hours from 9am to 3pm. It is wise to discuss all forms of possible shading.
Where shading may occur on a small aspect of the array, or panels are installed on roof space facing different locations, it will be beneficial to make sure the inverter installed has the multi-string option to allow for this. This will mean the solar array's power output, is maximised at all times for the installed location.
In the southern hemisphere, a north facing roof is the best for solar power. If your roof is not facing north, you need to be aware of the following losses :
If you are matching your solar system to your electricity usage under the roof, to maximise your electricity savings, then adding more panels is one way to compensate for these losses.
Roof Angle And Tilt Frames
A lot of attention is often focused on the angle of the panel, by many solar sales companies and householders. Did you know the angle of the solar panels does not affect the output of the solar system to greatly? In fact you will only lose around 1% per 5 degrees of roof angle. In Sydney the ideal angle is around 25 degrees. So the loss would be only 5% if the panels were laid flat.
Laying the panels flat though, does have other issues to be aware of, such as water run off and pooling. Other factors being dirt and vegetation not being washed off by rain.
One solution instead of tilt frames is to install more panels, to compensate for the loss. One more panel on a 3kW solar system, will more than compensate for the 5% loss. 5% being 150W, whereas one extra panel of 250W will be a far cheaper option than tilt frames.
Summer is often thought by many householders as the winner for solar output. It is a fact that the days are longer and sun is higher and more intense. Though this is the case, the intense heat from the sun, does in fact reduce the output of any solar panel.
A solar panel for example may produce 20% less energy than it's peak on a 40C day. This is why solar output over the year, often reaches it's peaks, during spring or autumn. Overall though, summer production is often the greatest.
When researching solar panels the temperature coefficient, is the figure that guides you to any panel's ability to handle heat. This temperature coefficient figure will tell you the loss due to surface temperature, for every 1 degree over 25C for example.
This is why when researching Solar PV Panels, it's important to make sure the chosen panel is specifically made to handle the harsh and hot Australia environments.
- Choose panels suitable for the Australian climate
- If shading is present, or panels are to be mounted on different facing rooftops, then choose a multi-string inverter
- Preferred orientation is North, NW and NE
- Way up the cost and advantages of tilt frames over adding extra panels
And where losses are forecast, adding extra panels is often a cheap way to reduce the loss. It all really depends on the available budget and the forecast savings expected.
Aussie Home Energy : Helping You Maximise Your Solar Power Output