When sunlight hits specific types of silicon, a small amount of electricity is generated. This is known as the photoelectric generation effect in which the surface of a photovoltaic (PV) solar cell ejects electrons as a response to sunlight. Therefore, transferring sunlight into electricity.
Sunlight is made up of photons, which are then reflected or absorbed by a solar cell when meeting. The photons that are absorbed will generate PV electricity. A system with increased efficiency will aim for more cells being absorbed as opposed to reflected.
The electron will move along the current that flows through electric ribbons that connect the solar panels together, in order to generate direct current (DC) electricity. This DC electricity will then be converted into alternate current (AC) electricity by your inverter, making it suitable for household energy.
There are 3 key components:
- The solar panels;
- The inverter which transfers DC electricity into AC electricity that is suitable for household use;
- Mounting frames, safety switches and cabling, etc that balance the system
To check if your system is functioning properly, you can check the inverter to see if the indication lights are on, and if the display panel shows how much electricity you have generated so far. If your inverter is dead, is not showing any lights or display, then your system has probably shut down for safety precautions, or sunlight levels are too low to operate. If your inverter seems to be turned off, check your power meter is on. Also, try comparing your current electricity bill with a previous bill.
A solar system can only generate electricity when the sun is out and will not generate any energy at night. However, a solar system will still work in overcast conditions.
As a solar system does not generate energy at night a grid connected solar system will pull energy from the grid to ensure your home is still running as normal.
If you have added battery storage and your system has generated excess energy during the day you will be able to use this excess energy at night as opposed to relying on the grid.
The most considered benefit of installing a Solar Power System is financial. Once installed a solar system produces electricity from the sun free. A Kilowatt hour of electricity used from the Solar System is a kilowatt hour of electricity that does not need to be bought from the electricity retailer. The more electricity that can be used from the solar system and therefore not paid for from the grid, the more money will be saved. As electricity prices increase over time, the greater the financial benefit of having solar becomes.
Solar power is also a great way to bring clean energy to your home, and reduce your family’s carbon footprint. In today’s society we are often removed from the source of the electricity we use, and therefore unaware of just how much pollution we create.
You may also qualify for some small rebates that can help with the initial cost of solar panel installation.
There are variations in the payback period on a solar system depending on the electricity usage pattern, the amount of local sunshine, and the local electricity prices. The greater the input of electricity relative to the output of electricity on the grid; the quicker the payback period on the solar system.
Generally, the payback period ranges from five to eight years depending on the latter factors, demonstrating how important quality and reliability in equipment is, as the solar system owner will only receive payback after their initial outlay has been paid off. For example, if it takes you more time to pay off a system than the system even lasts for, you have lost some of your investment. Conversely, if it takes you sometime to pay off your system, but it lasts for years, you have more time to receive payback. As such, a poor quality system will not be beneficial for a long term investment.
The sizing of your system will depend on:
- The amount of unshaded area available on your roof for installation
- The amount you are willing to spend (a cheaper system will unlikely to be a great quality)
- The amount you wish to generate or offset in relation to your consumption
In order to calculate what size your PV system should be, you must work out your household electrical consumption. You generally only require your system to produce the electricity at the time you are going to use it. Ie. Systems are better suited for households which will be home during the day when electricity will be generated, or households which have an electrical storage system in place.
Micro inverters are attached to each solar panel in a system, and is used to convert solar panel power from DC electricity to 240v AC electricity. This is used instead of conventional string inverters which connects to a string of solar panels and converts Direct Current (DC) power into Alternate Current (AC) power electricity.
Micro inverters are beneficial where there are issues with shading across the solar panels, or in cases where the roof design requires the panels to face different directions. The purpose of micro inverters is that they enable panels to work individually, so that if one or some panels are shaded, it will not affect the output of the entire system.
In order to maximise your solar systems efficiency in situations where there may be a small roof that can only fit a few panels, or the roofs face different directions, a micro inverter would be your best option for solar installation. Micro inverters enable for panels to be mounted onto differing directions, as opposed to string inverters which require all panels to be facing the same direction.
Micro inverters also monitor each panel individually, rather than as a collective, which makes system faults or poor performance easier to identify and repair. Furthermore, unlike a string invertor which, if it fails to work, the entire solar system will stop working, if a micro invertor fails to work, only that panel will stop working, whilst the others remain unaffected and will continue to convert power.
Additionally, if you are wanting to expand your solar panel, micro inverters allow for additional panels to be used, even if it is adding a different size or brand of panel. String inverters make it harder to expand, as specifications of added panels must match the existing panels.
Micro inverters have been used since the mid 1980s in the solar industry. However, the main recurring issue of micro inverters were their price, as they were never deemed as cost competitive. This has changed since 2011 with brands using smaller components entering into Australian markets now enjoying a small percentage of market share, yet micro inverter systems still remain the slightly more expensive option. Micro inverters are advantageous for specific residential sites such as those who require panels to be facing different directions, or those sites with partly overshadowing.
Here are the following steps for troubleshooting and repairing your system:
- Ensure that no solar generation is being measures on your inverter
- If the solar circuit has tripped you should turn it back on at night. If it trips again then there may be a serious fault.
- Call your original installer/ supplier to check the system
- Ensure you have the original paperwork if you want to make a warranty claim
- Check that your original system has not closed down due to being a bankrupt company
Any obstructions such as dirt, leaves, twigs, etc. will reduce your system’s output as it does not allow the sunlight through the panel, making your system lose efficiency. The difference between a dirty panel and a clean panel is that output can decrease by 5%. Heavy rain can assist in cleaning the panels which will maximise its output.
NOTE: Please do not try and clean your panels yourself, but rather get them cleaned professionally every few years.
When panels are being cleaned there should only be water being used, and no abrasive tools. If you live in a typically polluted area or a high traffic area, you may require cleaning once a year.
For situations where there is shading over the panels, or where the panels are required to face different directions, micro inverters will be your best option. However, this is the more costly option.
Conversely, string inverters will be more likely the better option in situations where shade is not an issue and all panels can be installed in the same direction on the same roof surface.
Traditionally, strings of panels would fail to work where there was shade, as if one panel did not work, it would damage the output of the rest of the panels. With bypass diode in higher quality panels, individual cells that are negatively effected will no longer affect the overall output of the system.
There are a number of factors which determine the extra energy produced by micro-invertors, including the system design, the specific issues of the site/ roof, and the actual solar module efficiency. In comparison to string inverters, micro inverters are said to increase yield by 25% in heavily shaded areas, but in most cases yield would be 5-10% for areas with no shading.
Some reasons as to why your system is producing low output could be due to: a defected inverter; build up of dirt on the panels (ie. Leaves, bird droppings, dust, etc); the panels were not installed on the correct angle to maximise efficiency; and there may be a lot of shade during the daytime.
For all the above situations, and potential other cases, it is best to call the original installer to organise for them to check your system.