This page contains details and frequently asked questions for Sunny Shire’s Rooftop Solar Bulk Buy 3, which started in early 2018.
Our bulk buys 1 and 2 have seen over 45 households install solar during 2017/18, with a total capacity of over 520kW. These households are now enjoying significant reductions in their electricity bills and the knowledge that they are helping with the shift to a more sustainable energy system.
How does the bulk buy work?
How do I register?
Please register using this Google Form.
Why get solar through Sunny Shire’s bulk buy?
- Organised by passionate, expert volunteers from your local community.
- Unbiased advice. We don’t have a financial interest – we just love helping people take control of their energy use and costs whilst improving the sustainability of our energy system.
- Community support via the Sunny Shire volunteers, the website and Facebook group.
- Support local solar companies based in the Sutherland Shire.
- Excellent equipment at very good prices. We’ve taken the hard work out of choosing from the large number of brands and models on the market.
How good are the prices?
Quotes obtained through the bulk buy should be very competitive with other suppliers. We encourage participants to compare offers if they wish – we don’t mind where you get your solar from – we just love seeing more solar on roofs! Just make sure you are comparing apples with apples: all the equipment offered in the bulk buy is top-tier; there are cheaper panels and inverters on the market but as with most things you get what you pay for. Our goal is to help people get the right setup for their home using quality equipment and installers.
|Fronius Inverter||5 years||Inverter warranty can be extended to 10 years for free, see here.|
|SolarEdge Inverter and DC optimisers||12 year inverter
25 year DC optimisers
|Inverter warranty can be extended|
|Trina panels||10 year manufacturing
25 year output
|LG panels||12 year manufacturing
25 year output
Number of Panels
Note: this table is just a guide – you don’t have to get exactly this many panels. The installer can advise when they provide a quote.
What size system should I get?
The right size will depend on various factors including your budget, availability of suitable roof space and your objectives. It is easier and cheaper to install a larger system up-front rather than starting smaller and adding panels later. This article provides several reasons for “going big” up front. This article presents an economic analysis showing that larger systems should save more money over time, despite the larger up-front cost and regardless of how much energy your household uses.
If your objective is to be as self-sufficient as possible then you’ll probably want a larger system. A 5kW system will produce about 19kWh per day on average. This is roughly equal to the average daily energy use of a fairly energy-efficient household. During winter it will produce less than 19kWh and during summer it will produce more. Installing an inverter larger than 5kW on a single phase supply requires permission from the network operator, although this permission is often granted. If such permission is required it will be arranged by the installer.
10kW systems require a three-phase supply. If you have a single-phase supply the largest system you can get would be around 7kW or 8kW.
Can I have 6kW of panels with a 5kW inverter?
Yes, it is possible and generally recommended to install more panel capacity than the inverter’s rating. This is called “oversizing”. A multiple of 1.3 is the maximum, eg a 5kW inverter can support up to 6.5kW of panels. Oversizing will result in greater energy output and does not damage the inverter. Oversizing will increase the price but is good value per additional kW because the STC rebate is based on the capacity of the panels (not the inverter) plus the installation cost doesn’t increase by much. The installer can provide more details and a quote for your particular situation.
Can I get a different size to the sample prices, eg 4kW?
Yes. You can get any size you wish. Discuss your requirements with the local solar company and they will quote accordingly.
Which inverter should I choose?
Both options (Fronius and SolarEdge) are quality, high-performing products. The main benefit of the SolarEdge inverter is the use of DC optimisers on each panel. This allows for increased system output in the following cases:
- partial shading of some panels
- differences in the orientation and tilt of panels
- differences between panels caused by manufacturing variation, dirt, bird droppings etc
This article demonstrates how the SolarEdge system can produce more output even if there are no partial shading issues.
The Fronius inverter supports two groups (or “strings”) of panels and requires all panels in a group to be installed with the same orientation and tilt. If this is not possible on your roof and/or if you experience partial shading then the SolarEdge system may be a better choice. The installer can advise on your particular situation.
The SolarEdge inverter also comes with a much longer warranty: 12 years vs 5 for the Fronius, although the Fronius warranty can be extended to 10 years for free for a limited time.
Which panels should I choose?
Both options (Trina and LG) are quality, high-performing products.
The LG panels are one of the most advanced panels on the market. They:
- produce more power per panel: 330W vs 295W for Trina, so less panels are required for a given system size
- should produce more power in low light situations
- have a 12 year manufacturer’s warranty vs 10 year for Trina
- more details about the LG panels are explained in this article
The LG panels are more expensive. The Trina panels produce more output per dollar of cost compared to the LG panels and may be more economical in most situations, particularly if your roof has plenty of space.
What is consumption monitoring? Why does it cost more?
The consumption monitoring feature provides monitoring and reporting of your household’s energy use in near real time and recorded every 15 minutes. This feature provides insight into when your home uses energy and how much, providing crucial information to manage and optimise your self-consumption. For example, you can determine how much energy your dishwasher uses and when to run it so it can be powered by solar energy instead of importing energy from the grid. This will save money, which will help offset the additional cost of the monitoring option. It also monitors imports and exports from the grid which can be used for double-checking your electricity bill.
Both the Fronius and SolarEdge inverters require an extra device (an energy meter) to enable consumption monitoring, hence the additional cost. Without consumption monitoring both inverters will only monitor PV output, and the only visibility of energy imports and exports will be your electricity bill.
Do these systems support a battery?
Yes, all systems here support adding a battery in the future. If you are considering getting a battery in the near future please discuss this with the installer.
Will these systems let me go “off grid”?
No, all inverters offered here are grid-tied and must be installed with a connection to the grid.
What happens in a blackout?
The Fronius inverter and the regular SolarEdge inverter can not function during a blackout. It is not possible to generate or use solar PV electricity during a blackout with a grid-tied inverter.
If you want a system that provides power during a blackout you will need a battery. Please speak with the installer about your requirements.
How does the monitoring work?
Solar PV systems provide detailed monitoring of your solar production, and also home energy consumption and excess solar exports with the consumption monitoring options.
The inverter connects to your home internet connection via Wi-Fi or Ethernet cable and send monitoring data to a system on the internet.
You can view your monitoring data from anywhere with an internet connection. Both systems provide apps for Android and Apple IOS. You can check the performance of your solar from work!
What if I don’t have a fixed home internet connection?
If you don’t have an always-on internet connection in your home (eg ADSL, Telstra/Optus Cable, NBN) you can still get solar – but the monitoring won’t be available unless you chose a solution that has its own internet connection. Please speak with the installer for more details.
Is my roof suitable for solar panels? Do they have to face North?
A decade ago solar panels were pretty much only installed facing north as they generate the most energy that way. But since the cost of solar has fallen so dramatically it is now economical to face them in any direction, including south! North-facing panels provide the most energy over the year, while west provides good output in the afternoon – useful for running air conditioners on hot days. East is good for getting energy in the mornings for your coffee and toast, and south may still be worthwhile if there is no space for more panels in other directions.
Most roofs are suitable for solar panel installation. If you have any concerns please mention them and the installer will speak with you about them.
Will I need to upgrade my electricity meter?
Your home will probably need a new digital net meter. This is required by your retailer to correctly calculate energy imports and exports. If your home currently has the old spinning disc meter it will definitely require a meter upgrade. If your home already has a digital meter you will still need to notify your retailer after installing solar as the meter may need to be reconfigured for solar.
Since December 2017 all new meters must be digital (smart) meters, and must be organised via your electricity retailer. The solar installer can no longer arrange a new meter.
Most retailers are offering free meter upgrades, although the wait time varies between retailers and may be several months. You should contact your retailer when the solar is installed.