Solar System Efficiency

It is worth taking time to understand some of the factors  that influence solar power system efficiency, so when getting solar quotes, when it is being designed and once your system is installed, you have a good idea as to what exactly is determining the solar energy the system produces.

Photovoltaic System output Influencers:

  • Angle of pitch of the solar panels. In Brisbane around 28 degrees is the ‘optimum’ pitch to produce maximum solar electric output from the installed solar panels. flat roofs can be acceptable for panel installation by use of solar ’tilt-kits’ which angle the panels correctly   solar system efficiency
  • Ambient temperature. Solar panels out less electrical energy with increasing temperature.
  • Solar Panel Age – Solar electrical output from p.v. panels degrades over time. most manufacturers ‘de-rate’ their panels – eg: many in the industry will publish a rating of 80 percent of the panels rated power at the 20 year operating age.
  • Shading. Shadows cast onto the solar panels from nearby trees and buildings, even t.v. antennae can have a huge impact on the output of  p.v. (photo-voltaic) system. Remember at design stage to ensure that a shade analysis is done of your property that takes into account the different seasons as shading patterns change throughout the year.
  • Orientation. Panels need to facing as close to a northerly direction as possible, so an east-west running roof is preferable. There has been some valid discussion (and implementation) of westerly oriented solar panels for some installations when afternoon electrical usage in the property is at its maximum. In a low feed-in tariff environment you need to use the maximum of solar power in your property (ie; export none or very little of the electricity your system produces). If you are using a lot of power within your home in the afternoon / late afternoon then westerly oriented solar panels could be worth considering and discussing with the system designer.
  • Cable losses. though this should not be an issue, use of low grade wiring between the solar panels and inverter and the length of the ‘run’ of cable can, potentially result in power loss of the system.
  • Dirt and debris on the solar panels. An industry has sprung up in brisbane to cater for cleaning of solar panels in the last couple of years. In general solar panels are pretty much ‘self cleaning’ however regular inspection is recommended. dust storms, bird mess and the likes canresult in decreased output from the solar panels.
  • Solar Inverter Efficiency. Most modern solar inverters have efficiency levels approachinh the high ninety percent levels, meaning they are extremely efficient at conversion of the direct current generated in the p.v. modules to the a.c. we use in our home.
  • Solar Module Mismatched characteristis. Lower cost panels may be manufactured to less exacting standards than premium panels. When the solar panels are connected into the system this ‘mismatch’ can result in an overall loss of system efficiency – not a good thing.