Solar power in Australia has never been so cheap, and with generous government incentives still available it is now becoming common for a large household to install a 10kW-20kW solar system. Let’s have a look at the key numbers of a 15kW solar power system, including the price, the output, and the brands you should be considering for a system of this size.
Price of a 15kW Solar System
The price of a fully installed 15kW solar power system in NSW has fallen dramatically in recent years, and government incentives are still available.
A good quality 15kW solar power system starts at around $16,000 fully installed, including a European-Made inverter such as the Fronius Symo, premium tier-one solar panels such as Trina Honey 275W modules and a standard installation (ie. no cherry pickers etc). It is also popular to put a 15kW solar system on a repayment plan for around $330 a month over 5 years.
It is important to remember that with solar panels you generally get what you pay for, and most of our customers choose high-efficiency panels from manufacturers such as LG Solar.
It is possible to find a cheaper 15kW solar system for under $16,000, however, this will typically require buying low to mid-range panels manufactured in China, and often without any after-sales support. For a larger system of this size it is important to maximise reliability, output and of course longevity, and so spending a little more upfront can save you a lot of money over the life of the system.
Solaray service full-replacement warranties and include full technical support. This gives our customers the peace of mind that if something goes wrong you will be looked after.
As a rough guide, a 15kW system can save you up to around $6,000 a year on your power bills. Of course, to save $1,500 on a quarterly bill you are going to need to use a lot of power during the daytime – as much as 80 kWh during the daytime over summer. If you are able to get the most out of your 15kW system, you could spend up to $24,000 and get a top of the range system with a return on your investment in only 4 years!
A 15kw solar system will also reduce your household’s CO2 emissions by up to around 300,000 kg over 15 years.
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Output of a 15kW Solar System
According to the Clean Energy Council guidelines, a 15kW solar system in Sydney facing north will produce an average of around 60kWh a day, outputting more power in summer and less in winter. We have found that this guideline is a conservative estimate and that by using the top brands you can get considerably more out of our system, for example, our Enphase systems give our customers on average 110% of expected output.
On a sunny day in summer, a 15kW system will often give our customers over 90 kWh of power. Because this can be too much power for many households, we often recommend splitting the panel array across two orientations to distribute the output of power across the day, and to consider battery storage so that any excess solar power can then be used during the evening.
A 15kW Solar System - The Key Numbers
|Number of Panels||From 41 x 365W Panels to 54 x 275W Panels|
|Output||Around 60 kWh a day average (see below)|
|Potential Savings||$1200 – $1600 a bill depending on your cost of power and how much solar power you use in the home|
|Average Payback Period||3 to 6 years|
|Cost||From around $16000 to around $25000|
|Repayments||From around $330 a month over 5 years.|
|Suited to||larger homes using on average around 60 kWh a day during the daytime (or over 24 hours with battery storage)|
How much will a 15kW solar system save me?
The potential savings from a 15kW solar system depend on how much solar power you are able to use in the home at the time of generation. You will typically save around 22 to 30 cents a kWh (depending on how much you pay for your power), and depending on your retailer, you will be paid around 5-13 cents a kWh for the power you send back to the grid. A 15kW solar system can save you up to around $1200 to $1600 per quarterly bill.
More information is available here: How Solar Power Reduces Your Power Bill
Number of solar panels for a 15kW System
The larger the system, the more important it is to buy quality panels to ensure you maximise reliability, increased output in all weather conditions and the longevity of the system.
The other consideration is roof space. By installing high-efficiency panels, we can use 41 x 365W panels instead of the standard 54 x 275W panels.
15kW Micro Inverter System
Solaray is the largest and most experienced installer of Enphase Micro Inverter systems in NSW, and our system design team are experts at putting together a professional solar array that will maximise solar output in all conditions.
The main benefit of microinverters is that each panel is independent of the others, making it possible to design an array across different orientations and at different angles. A common panel layout is to have some panels facing north, and the others west to spread the output of solar power across the day, making it easier to use more of the solar power as it is generated. Having panels west is also advantageous if you are on time of use billing, where households typically pay around 50c per kWh between 2 pm and 8 pm for power.
On larger residential systems, the panels in the middle of the array can get quite hot during summer as air flow under the panels is less than ideal. When panels get too hot, the output can be significantly reduced. Because of this, we recommend using microinverter technology and in fact, over 80% of our systems now include this technology. Find out all you need to know about Enphase: 10 key benefits of microinverter systems.