Solar power in its various forms can certainly be confusing if you’re new to the world of renewable energy. Below are some of our solar power FAQs with answers to common solar questions in relation to residential and commercial systems.
Your solar system works by converting light from the sun into energy which you can use in your home or export to the grid. Panels on your roof generate DC (Direct Current) Electricity, this is fed into an inverter which converts the DC electricity into 240 volt AC (Alternating Current) Electricity which can be used in your home. See here for more information.
If you need more information than what’s provided in our solar FAQs, give us a call on 0422 975 591.
A typical grid connected solar energy system consists of the following components:
Panels – The panels convert sunlight into DC electricity and then feed this electricity to the inverter.
Inverter – The inverter converts the electricity produced by your panels from DC electricity to AC electricity which is what your appliances use. The inverter also records the electricity produced and on some models, can communicate with your computer.
Bi–directional meter –Your meter records energy drawn from and sent back to the grid.
Mounting System/ Mounting Frame – This is what connects your system to the roof.
Your system will still produce electricity during cloudy days however production will be less than on sunny days.
The amount of energy produced by the solar system depends on the following factors:
Panel Orientation – A system facing due east or due west will produce around 15% less than one facing due north.
Roof Pitch – A 30 degree pitch is optimal however you will only lose around 1% production for every 5 degree deviation from this.
Weather – Australian cities in general and Perth specifically is one of the best cities on earth for solar due to the many hours of sunshine per year.
System Capacity – The larger the system, the more energy will be produced.
Shading – Solar systems hate shade, small amounts of shade during 9am – 3pm can have a strong effect on production. Shading outside of these hours in certain circumstances is acceptable however it’s best for us to complete a shade analysis if you have any doubts. In the case of shade using micro inverters can be very useful, as these will minimise the effect of shading on solar output.
Before you go Solar
Considering to go solar? Here’s a list of frequently asked questions. For more information, contact Solar2020.
Yes. All installations under 100kW (and systems with an annual electricity output of less than 250MWh) are eligible for Small-scale Technology Certificates, or STCs for short. It is a form of rebate and for a 6.6kw in Perth currently adds up to around $3000 per year. You’re eligible for STCs whether you’ve previously accessed a rebate or not. It’s also not means-tested and is accessible by everyone. The solar PV system or product you purchase in order to receive STCs must adhere to the Clean Energy Council (CEC) design and install guidelines, only use panels and inverters on the CEC approved list, comply with the relevant standards (like AS 4777), and be installed by a CEC accredited installer. Solar2020 meets all these requirements.
In most cases, we can make an effective system using the space available. However, it doesn’t hurt to set aside some space on the north-facing and western roof for at least 10 panels each. A common panel these days tends to be 1.7 m x 1.0 m, so a little over 20m² for 10 panels will give you over 3.6 kW. However, if you want more panels and a larger system, you will need additional roof space. You’ll only lose approximately 15% of energy yield if panels are installed on the east or west (compared to north-facing panels), so we often incorporate these aspects too to make the most of the roof space you have available.
It’s often difficult to size a system on a new build as there’s no history of power usage. For this reason, we usually stick to common sizes like 6.6 kW. Note that for a single storey home, it’s just as easy to install after the build is complete. For two-storey installations we advise that you consult with us directly as it may be advantageous to complete some of the work during the build. Other things you can do to prepare include:
- Allowing for wall space in the garage or under eaves on a sun-free (south-facing) wall for the inverter. If this is on a cavity wall then a surface conduit can be avoided, making for a cleaner more aesthetic installation.
- If you’re smart wiring your home, consider a data point near your inverter to ensure the monitoring devices function without any drop outs. Alternatively, ensure the WiFi signal is strong near the proposed inverter location.
- Consider smart appliances which can be set to run at times when solar production is high. This will increase your self-consumption and the savings generated by your system, as it will help produce less excess and ensure that energy isn’t diverted to the grid or other ancillary systems.
- The best way to save on energy costs is to reduce your consumption, so take the opportunity to build a house that is well insulated and as energy efficient as possible – it will be worth it in the long-term.
STCs are Small-scale Technology Certificates. These certificates are a tradeable item and are created when you install a small-scale renewable energy system, such as solar power systems, solar hot water systems or heat pumps. These STCs fluctuate but are currently worth around $35 each, which equates to around $3000 on a 6.6 kW system in the Perth area. Almost all solar companies will quote you a price with the discount factored in, meaning you only have to pay the remaining amount after the “rebate” is factored in.
For hot water and heat pumps, the number of STCs is best determined by going to the REC registry website and putting in the details of the system, as they maintain the most up-to-date catalogue of information. For solar power, the following formula is used, which factors in system size, location and when it’s installed:
STCs = System Size (kW) x Zone Multiplier x Deeming Period
The system size is the total kW output of the system you’re installing. The zone multiplier is one of four values assigned to each postcode in Australia. This number is based on how conducive the postcode area is to solar production and includes the average solar radiation as well as other factors. The deeming period is the number of years the system will (on average) be operational, which is set by the Clean Energy Regulator (12 for installations in 2019, but reducing by one each calendar year). You can’t claim part of an STC, so round down at the end, as decimals are not allowed for.
A 6.6kW system in 2020 will give you 98 STCs in Perth, (Perth, Brisbane, Sydney, Adelaide are all zone three). And will be less in 2021 due to the yearly phase-out of the rebate. If you were to install a system in zone four areas, such as Melbourne (VIC), Hobart (TAS) or Albany (WA), you would receive fewer STCs – this is because the same size system in these cities produce less energy comparatively due to climate conditions. Likewise, if you were to install in a zone two area like Darwin (NT), you would attract more STCs thanks to the higher than average energy production.
When it comes to how much you can save with solar, this will vary between households. Below are the factors which can impact your savings.
- System production – The more kWh of energy your solar PV system produces, the more you are likely to save. However, system production is not just determined by the system’s size. It also comes down to other factors such as the location of the installation, site conditions (eg. pitch, orientation, direction), and the quality of the components used in the solar installation etc.
- Energy prices – As energy prices increase, the worth of your kWh production will only grow. Your buyback (sell) rate is also a factor in this equation, as the more you can get for excess solar production, the greater your savings will be and overall return from solar. In Perth recently the Government has reduced the FIT rate to 3c in some parts of the day and to 10c in the period from 3pm to 9pm. For this reason it is worthwhile to have appliances like pool pumps using electricity during the day to minimise export.
- Self-consumption – When you produce solar power, you can either use it yourself first or sell this excess energy back to your energy retailer or the grid. The savings generated from self-consumption are usually greater than selling back to the grid, which is why many homeowners try to maximise their savings by using this method.