10kw solar system - Complete 2021 Guide

Updated: January 26, 2021

With the price of solar panels plummeting in the Australian markets, an increasing number of homeowners with large homes are taking interest in the 10kW solar system.

Being among the largest solar systems in the market, this system generates more electricity for high power consumers. Below is an in-depth review of this system and why it’s a good investment for your home or office.

How much does a 10kw solar system cost

On average, most Australians pay $10,750 for a quality 10kW system installation. However, the price can go as high as $14,000 and as low as $9800 after the government rebate.

You’ll, therefore, pay higher or lower depending on the rebate rates of your state. For instance, Homeowners in New South Wales and Victoria may pay more than homeowners in the Northern territory since their solar rebate rates are lower.

How much power will a 10kw solar system produce?

Ideally, the 10kW solar system should produce 40kWh per day.  However, this output is subject to the solar system’s location, the panel’s array tilt angle, and orientation.

Temperatures and shading may also affect the system’s efficiency.

The output also varies depending on the season of the year. Your 10kW solar system is more likely to generate more electricity during summer than winter.

Below is a table of the average production per day of a 10kWh by major cities.

CityAverage Output (Daily)
Perth40 – 44kWh
Sydney34 – 38kWh
Canberra36 – 41kWh
Melbourne32 – 36kWh
Adelaide36 – 41kWh
Hobart29 – 33kWh

How many panels does a 10kW solar system need?

A regular 10kW solar system requires about 27-34 solar panels. The precise number of panels you’ll need depends on the wattage of each panel.

If the panels have a 350-watt rating, 29 panels will be enough for your system. However, with about a 300-watt rating or lower, the number of panels needed will also increase.

To put this into perspective:

10000 watts / 350 watts = 29 panels

10000 watts / 300 watts = 34 panels

How much roof space will I need?

27 – 34 solar panels mean that you need a lot of roof space. Since most solar panels measure 1.6m x 1m, you’ll need at least 54 – 80 square meters in space, depending on panel wattage.

If you have little roof space, you can opt for the latest more-efficient panels. They generate more electricity with fewer panels of the same dimension but are more expensive than the regular PV solar panels.

What’s the government rebate on a 10kW solar system?

The Australian government’s solar rebate program, the Small-scale Renewable Energy Scheme (SRES), provides huge incentives and rebates on PV solar systems, making it cheaper for homeowners looking to go solar.

The rebate comes in the form of Small-scale Technology Certificates (STCs), which are tradable for a discount on your system’s price. Each STC is worth around $34-$40.

For a 10-kW solar system, the total rebate amount you’ll receive greatly varies with the state you live. Normally, states with higher sunlight hours will receive higher rebates than those with lower sunlight hours.

Below is a breakdown of how much you can expect as a rebate for your 10kW solar system by State.

StateRebateCost after rebateAvg. annual savings
New South wales$5,130$8,640$1465 – $2,327
Victoria$2,941$10,400$2,038 – $2,745
Queensland$6,019/ $5,130$10,800$1,254 – $1,822
South Australia$5,130$10,170$2,213 – $3,140
Western Australia$5,130$9,100$1,940 – $2,888
Tasmania$2,941$10,820$1,680 – $2,496
Northern Territory$6,019$10,830$2,050 – $2,842
ACT$5,711$8,240$1,736 – $2,202

Who is eligible for this rebate program?

Anyone looking to install a solar system in their home is eligible for this rebate program. Your only requirements would be having a system less than 100kW and enough capital to cover the remaining costs after rebates.

You’ll also have to apply for the rebate through a registered solar retailer. The retailer will give you a point of sale discount based on the STCs you’re entitled to; then, they can later complete the application.

This makes the process hassle-free and very convenient.

Alternatively, you can apply for the rebates as an individual through the Clean Energy Regulators portal. For this, you’ll first need to have a solar system (10kW or less) installed in your home.

Once you receive your STCs, you’ll then have to look for a way to sell them through any Australian STC trading site.

Is the solar rebate program ending?

Yes. Unfortunately, the Australian government is slowly phasing out the solar rebate program. It is expected to end by 2030.

In the meantime, the rebate amount reduces by 1/15th each year. But this is no reason to worry. With over 10 years left on the program, you can still install a solar system today and enjoy a substantial government rebate.

How much money will I save with a 10Kw solar system?

Your savings by going solar will depend on your household’s power consumption. The more power you use in your home, the more savings you can make with a 10kW solar system.

For instance, Australia’s average cost of power production is 25c/kWh during the shoulder period. During peak hours, this rate could go as high as 50c/kWh.

If your home consumes 25kWh per day, your daily power costs will be: 25 x 0.25 = $6.25

Monthly, your home consumption will approximately be: $6.25 x 30 = $187.50

Annually, your power bills will be: $187.50 x 12 = $2,250

Now, if you invest in a 10kWh solar system, you can drastically eliminate this power costs from day one. With the average cost of solar power production being a mere 5c – 6c/kWh, here’s how much you can save:

Assuming your home consumes 25kWh daily, this solar system will save you the annual $2250 you spend on power bills. Additionally, the extra 15kWh produced by your system could be fed back to the grid through the feed-in tariff program.

If your utility company pays you 10.2c/kWh for the energy you send to the grid, you’ll save an extra: 15 x 0.102 = $1.53 daily. Monthly this will be $45.9 and yearly, $550.8 

In total, you’ll save: $2250 + $550.8 = $2,800.80 annually.

If you use the entire 40kWh daily, you may end up saving = 40 x 0.25 = $10 daily or $300 monthly. Annually, this converts to $3,600 in savings.

How long will a 10kW solar system take to pay for itself?

Most solar systems usually pay themselves back within the first five years – but this is subject to change. Your 10kW systems may payback within 3-4 years, while others may take as long as 5 years. It all depends on your consumption.

If you’re using all the power generated at your home instead of feeding back to the grid, the system’s payback period will be shorter.

However, if the solar system is installed in a home you rarely use, like a holiday home, the payback period will be much longer. This is because you’ll be exporting most of the generated power back to the grid at a lower feed-in rate.

That said, assuming you bought your 10kW solar system at the average of $10,750, and your annual savings (from above) is $2,800.80, your system will pay itself back after:

$10,750 / $2,800.80 = 3.8 or 4 years.

When using the entire generated electricity (saving $3600), the payback becomes:

$10,750 / $3,600 = 2.9 or 3 years.

Again, this period might increase or decrease depending on the price you paid for the system, as well as your consumption.

Can a 10kW solar system power a house?

Yes! The average power consumption for an Australian home is 22kWh per day. The 10kW solar system produces nearly double that amount in a day at around 40kWh.

For a small house, this would be more than enough to run the entire home and feed the surplus to the grid. However, with the cost of a 10kW system being relatively high, smaller homes are advised to invest in smaller solar systems – maybe the 5kW system or the 6.6 kW system.

Opting for this system based on its high electricity generation will mean a longer payback period for small homes. If you consume less than 40% of the total generated electricity from the 10kW system, that’s a poor investment.

The 10kW solar system is a good choice for large homes or small offices with high daytime power consumption. It can also be a good choice for homes that want to go completely off-grid.

What battery size do I need for a 10kW solar system?

What battery size do I need for a 10kW solar system

If you want to use your solar system at night, or better yet, go off-grid, a solar battery is the way to go. However, you’ll need to get the right battery size for your 10kW system if it’s to work as you expect.

Under optimum conditions, your 10kW solar system requires batteries that can store 28kw (assuming you’re consuming 40kWh daily).

However, here are a few factors you’ll have to consider when choosing the battery:

Your power goals

Solar batteries aren’t designed to restore 100% of your operations whenever there’s a blackout. They should only be available to restore the essential appliances.

With this in mind, you can assess what you want to restore once there’s a blackout. This could be your lighting, refrigerator, air conditioning, and a few appliances. Having the list of these appliances, you can then calculate how much power they need and hence the battery size needed.

Duration of the back-up

Your next concern should be how long you need the batteries to last during a blackout. The longer you want your batteries operating, the bigger sizes you’ll need. You might also require multiple batteries.

Additionally, consider the space available for the batteries in your home to ensure they have a good storage area.

Your system’s power generation

A 10kW solar system generates 40 – 44kWh daily. And with most homes using just 30% of power through the day, the remainder 70% is consumed at night.

Your battery storage capacity

The battery size you choose should therefore be able to store the remaining 70% for use after hours.

10kW solar system price with battery backup

Now that you know how to size a battery for your 10kW solar system, you’ll need to know that solar batteries’ price can be a bit more expensive than the solar sysмtem. As earlier mentioned, the price of a 10kW system is $9,800 – $14,000.

Depending on the type of batteries and brand, the cost of solar batteries for a 10kW solar system ranges between $12,600 to $15,200.

Therefore, a 10kW solar system with a solar battery backup will cost you anywhere from $22,400 to $29,200.

If you need a cheaper alternative for your solar batteries, you can opt for lead-acid or sealed acid batteries. They are more budget-friendly but are only effective for low power consumption needs like lighting.

Is there a solar battery rebate?

Is there a solar battery rebate

Yes, but not for all Australian homeowners. While the federal solar system rebate is available for all Australian residents, the rebate doesn’t cover solar batteries.The only existing solar battery rebate programs are run by state governments. Some of the states running these rebate programs include; Victoria, South Australia, Australian Capital Territory (ACT), and South Australia.

Solar Battery rebate VICThe Victoria battery rebate known as the Solar home program that gives eligible Victorian homes a point of sale discount of up to $4,174 to help them install a solar battery.

Solar Battery rebate ACT – The ACT government has also initiated its Household Battery storage program, that seeks to help 5,000 homeowners within ACT install solar batteries through discounts and rebates.

Under the program, homeowners receive an $825 per kW for systems less than 30kW. Therefore, homes using 5kW solar systems may receive rebates of about $4,125. Those with 10kW systems may receive rebates of almost $8,250 on solar batteries.

If you’ve met these requirements, visit the ACT government website and follow the application process outlined.

Solar Battery rebate SA – In late 2018, South Australia’s government introduced the South Australia Home Battery Scheme. This program provides South Australian households with access to $100 million in state government incentives and another $100 million in loans to repay for home battery installations.

As of September 2020, homeowners could enjoy subsidies of up to $3,000 on home battery purchases. The subsidies are calculated by the kWh capacity of the battery.

How much is a Tesla Powerwall for a 10kW solar system?

Arguably the best solar battery in the market, the Tesla Powerwall solar battery uses one of the most advanced systems available. As such, it’s fairly expensive.

For a 10kW solar system, you’ll need 2 Tesla Powerwall storage batteries since the battery’s capacity is 14kWh and you need 28kW of storage power. You can, therefore, expect to pay between $20,000 – $23,000 for the entire battery installation.

By itself, a Tesla Powerwall 2 battery goes for $10,000 each. Please check your local state government rebate on batteries to see savings you are entitled to.


While the price of solar panels is falling by the day, whether you should buy solar now or wait is one decision you should weigh carefully.

Assuming you choose to wait, you’ll be saving almost $150 every year based on the current solar system market. Nonetheless, you’ll still have to pay more in power bills, thanks to the rising cost of electricity.

Moreover, the main reason for the cheap solar panel costs is the government incentive programs and rebates. As it stands, most state governments are slashing these rates, and others want to phase them out due to the rising popularity of solar power.

When this happens, the little savings you had each year will be outmatched. Therefore, while buying solar seems expensive now, it’s long-term benefits will be worth it.

If you buy solar now, you can take advantage of the government’s incentive programs, as well as the feed-in tariff to reduce its cost and quicken its payback period.

Most solar batteries will last for 5-15 years before needing replacement. The exact lifespan depends on the battery type and brand, as well as your charging and consumption habits. Tesla batteries, for instance, come with an 8-year warranty, assuring you that they’ll last long.

For a small home, 3-4 power users, a 5kW solar system is more than enough to meet your power needs. A 5 kW solar system generates 20kWh on average per day – which is almost equal to the average daily power consumption in most homes.

Yes. The price of solar storage batteries is drastically coming down.  This is because of the fast-growing battery manufacturing industry in the world market. A lot of research is also on-going to make the solar batteries much cheaper, safer, and accessible.

Yes! Installing a solar battery for your solar system is optional. You can use your solar panel to generate electricity during the day and send the excess back to the grid for utility credits. This will help cut down your power bills.

Solar batteries, on the other hand, only enable homeowners to store the surplus electricity generated during the day. You can then use the stored power at night or during days with low daylight hours.

Ben McInerney head shotAuthor: Ben McInerney is a renewable energy enthusiast with the goal of helping more Australians understand solar systems to make the best choice before they purchase. Having an accredited solar installer in the family helps give Ben access to the correct information, which allows him to break it down and make it easily understandable to the average homeowner.