Frequently Asked Questions
What are Small Scale Technology Certificates (STC’s)?
STC's are essentially the rebate you receive off your solar system (in the form of a point of sale discount). STC’s are similar to shares and have a dollar value that goes up and down depending on the market. Also, the bigger your solar system, the more certificates you get, therefore the bigger your rebate.
How long does it take to pay for itself?
Financial payback will vary depending on your circumstances, but with the available incentives plus the ongoing energy savings you can begin to recoup your additional investment straight away. Typically for a near north facing roof we see a return of around 15%. After you recover your initial investment, the savings are yours to spend on yourself and your family, year after year.
How do solar panels (photovoltaic modules) work?
Most solar photovoltaic modules use silicon wafers mixed with other elements to allow the silicon to convert light energy into electron movement (electricity). The electrical output of a solar module is directly affected by the intensity of the light – the brighter the light the greater the output. Solar photovoltaic modules prefer cooler temperatures, so cool sunny weather is the optimal environment for solar.
Please see our page on how solar works HERE.
Different Types of Solar Panel
At this point in time there are two basic types of solar module commercially available – thin film (or amorphous) modules and crystalline modules.
Within the crystalline category there are two sub groups – polycrystalline (generally a blue colour) and monocrystalline (almost black) modules. Crystalline panels are the most widely sold types of panels in Australia.
Thin film modules use less silicon and are quicker to manufacture than crystalline modules. As a consequence they are generally a little cheaper for the same power rating. The trade off is that they are about a third less efficient as crystalline modules in space efficiency. However, their physical properties mean that in our harsh Australian climate, they can out-perform crystalline modules in the heat, low light and partial shade.
Effect of Shading
Thin film and crystalline modules behave differently when partially shaded. If a crystalline module is partially obscured by solid shade, then the module will stop producing and system performance will drop markedly. If too many panels in a group are shaded, the entire group of panels may stop producing. Incorporating micro-inverters into a crystalline solar system can prevent this from occurring because each panel is isolated. Meaning that losing one panels' output will not affect the other panels.
Thin film modules on the other hand will continue to provide an output under such conditions, proportionally reduced by the area exposed to shading. Potential shading is an important factor in determining the best type of system for a particular application.
Solar modules can be fitted to almost any roof type – Steel (galv/colorbond), tiles (terracotta, cement, aluminium).
Aspect and Inclination
Ideally, the best arrangement for solar modules is north facing, inclined at an optimal angle for your location (35 degrees for Adelaide). Although an alignment within 15° of north, and an inclination of between 20° and 40° has less than 3% impact on performance.
Your technician will take these factors into account when designing your system in order to maximize your system output. Locating photovoltaic modules on the east or west roofs will reduce output (by up to 20%), but may make the most of peak usage and therefore be a better option for financial gain.
Solar Module Life
Life expectancy of solar modules varies enormously depending on the type and quality of the module. We recommend the use of modules with a performance warranty of better than 25 years with strongly branded manufacturers.
What’s the best size system for me?
There are three main factors to consider when choosing the right solar system for you:
- Household electricity consumption.
- Available roof space.
- Budget considerations.
Where practical, we would recommend that you aim for a system size that meets somewhere between 70% and 120% of your household energy requires in order to get the most out of your investment. It is very important to remember that a system of the same kW size, may not give the same kWh energy output. Always make sure to compare the energy output (measured in kWh - kiloWatt hours) when comparing systems.
With some planning and forethought systems can be designed to be expanded at a later date, you could start with a smaller system and build it up over time if desired.
Operation, Cleaning and Maintenance
Once installed, solar electricity generating systems are generally fully automatic and require no daily input from the owner of the system. Three or four times a year the surface of the solar modules should be cleaned with water to remove any build up of dust or dirt,
We recommend having your solar panels and electrical connections surveyed with an infra-red camera after having the system for two years. We also maintain and service solar systems to ensure that your investment is running smoothly and safely. Please contact us for further information about maintaining your panels.
Blackouts / Battery Back-up Systems
Grid connected solar systems will shut down during a grid blackout. This is so that power generated by the solar system isn’t fed back into the grid while someone is working on it. A Grid Battery Back-up system can be added to your solar system to provide you with power during a blackout. These systems can even provide you with power 24/7 so you can disconnect from the grid entirely! Contact us for more info.
Installation of a grid connected solar energy system usually means changing the electricity meter installed at your home. Your current meter will be changed to a digital ‘import-export’ meter. An import-export meter measures both the energy you consume from the grid, and any energy your solar system exports back to the grid. If you export more than you use, your supply company will send you a cheque!
SA Power Networks charges a fee for changing over to the import-export meter which is payable by you. If you are building a new home and are considering installing a solar energy system, you can request an import-export meter be installed from the outset. There should be no additional charge in this case. Single phase meters cost around $450.00, 3-phase around $650.00, and meters that can be re-programmed cost around $90.00. But we would advise you to contact SA Power Networks for accurate pricing as they may change fees without notice.