10 Things You Must Know Before Purchasing a 10kW Solar Power System


A 10kW solar power system is a great investment option for Australian households with high levels of energy consumption or business properties with comparatively small electricity needs. This article will take you through the 10kW solar system price, energy production, payback period and nearly everything you need to know about 10kW solar power systems.

  1. 10kW Solar Power Systems in Australia

The 10kW solar power system has become the foremost choice for many residential and commercial clients since an enormous upgrade in home solar, allowing 10kW solar systems. This upgrade raised the maximum inverter capacity allowed per single-phase connection from 5kW to 10kW, paving the road for systems with far greater potential. While the export limit remains the same as that of 5kVA for single-phase connections, large households and small businesses can still take advantage of cost savings.

A 10kW solar power system can wring out an average of 37kWh of solar power per day. Depending on the wattage of the solar panels offered, a 10kW solar package would include CEC approved 27 to 33 panels, CEC approved 10kW solar inverter, roof mounting and electrical kit approved for use in Australia.

  1. Is a 10kW solar power system the right choice for your needs?

There can be two major reasons you may consider a 10kW solar system despite the export limit. The first reason being that your home has a significant amount of daytime electricity consumption or your business has 40kWh of daytime usage. Second, you have low electricity consumption but you want to go off-grid. You need to first find out your average daily energy consumption to decide if this is the right system size for you. You can easily access this information from your latest quarterly power bill.

If your average daily electricity consumption falls between 31 to 40 kWh, then a 10kW solar system would be a safe choice for you. This is because it is recommended that you self-consume at least 30% of the solar energy that your system produces. So, if the members of your family stay at home throughout the day or you have electric cars or batteries, there is a good chance you would utilise enough daytime energy.

It will also allow you to enjoy more guilt-free energy consumption. The excess energy, up to 5kW, can then be sold back to the grid at a feed-in-tariff rate. On the other hand, if you are looking to reduce your reliance on the grid, you can use the excess power to charge the batteries for use at night.

  1. How many solar panels and how much roof space will you need for a 10kW solar system?

The size of a solar panel varies depending on its power output, which ranges from 250W up to 400W. A 10kW solar power system would normally comprise about 27-35 solar panels. This may require up to 80 m2 of roof space, depending on the wattage of panels. For example, let’s take 370W solar panels. So, with 27 x 370W solar panels you can achieve a 9.9kW solar system. Each 370W panel will cover about 1.8m x 1m, so you will require at least 48.6 m2 of roof space. Solar panels with newer technology can output higher energy for the same dimension panels but they often cost more.

  1. How much electricity can you expect a 10kW solar system to generate?

Several factors determine exactly how much energy you can expect a 10kW solar system to produce. These variables are:

  • Geographic location—e.g., Brisbane generates much more electricity than Melbourne.
  • Orientation and tilt angle of the solar panel array or pitch of the roof
  • Is there any shading over solar panels?
  • Operating temperature of the panels

On average, a 10kW solar system in Australia can generate approximately 40kWh per day. However, this number can greatly differ depending on the site-specific factors mentioned above. For instance, the average output of a 10kW system in Brisbane can be anywhere between 39-41 kWh, assuming 75% system efficiency for a north-facing solar panel array tilted at a 30° angle from horizontal.

This much electricity is enough to run 2-3 average Australian households. To put this in perspective, 40kWh energy per day can power 40 five-star energy rated fridges with top or bottom freezers. 

  1. How much would a 10kW solar power system cost?

10kW solar system price varies based on a range of factors like quality of panels, the location of your property, the type of roof you have and much more. So, there is no one answer for the price of a 10kW system. The solar providers in the Australian market offer different packages that range from budget-friendly to best in quality.

The higher quality solar panels will produce optimal energy output throughout their lifetime, last longer, require less maintenance, and operate at higher levels of temperature safely. This will ultimately provide a greater return on investment, so rather than focusing solely on the initial installation price, consider the long-term monetary gains.

According to the latest solar PV price index, the average 10kW solar system price in Australia is about $0.98 per watt or about $9,850. Although, if you go for the best quality system, professionally installed by a reputable installer, you can expect to pay around $8,000 out of pocket after deducting the amount you get from STCs (Small-scale Technology Certificates), also known as the solar rebate program.

  1. Returns on a 10kW solar power system

The key measurement of the returns gained from a solar system is no longer the fee-in-tariff credits. It has become the secondary benefit of having a solar system installed. The greatest benefit of having a solar system is combating the rising costs of electricity. With a 10kW solar power system, you will derive the most value out of the solar-generated energy and not by the feed-in-tariffs.

The feed-in-tariff rates are much lower than what you will pay for the energy from the grid. So, the more solar energy you consume yourself, the more you will save. So, you will make the most of it by directly self-consuming solar power as much as possible. This means you can comfortably use more energy, turn on the air conditioning when you like, use a dryer, bake more often and turn on the heater in winter.

The main return on a 10kW solar system price you pay is the increased energy available to use and to sell. If you consume more energy during the daytime, you will see great returns as savings on your electricity bills. Further, the excess solar energy will flow into the grid, earning you credits that will lessen your overall power bills.

  1. Savings and payback period for a 10kW solar system

The payback period will depend on how much solar energy you self-consume and how much you get paid for the exported electricity (feed-in-tariffs vary from the city to city). Depending on your energy retailer, feed-in-tariffs in Australia can pay anywhere between 7c to 20c per kWh of exported electricity.

Let’s say you pay 30c per kWh to buy electricity from the grid and get paid 8c per kWh exported. Now, you’ll see why self-consumption is more important with a 10kWh solar system. Consider that you are exporting half the electricity to the grid. In this scenario, you will save about $2,700 in the first year. Now, consider that you are using all the solar energy for your home or business. In this scenario, you would save approximately $4,500 in the first year itself. Furthermore, you will save around $150,000 over 20 years assuming an annual electricity price increase rate of 5%.

However, it is not possible to self-consume 100% of the solar energy, so let’s take another example: You installed a 10kW solar power system for your home in Brisbane, which cost you $9,940. You are paying 18c per kWh for electricity from the grid and your retailer is paying 5c per kWh energy exported. Assuming you are self-consuming 60% of the solar energy generated, then you will pay off the 10kW solar system price in 5.3 years with a 19% internal rate of return (IRR).

  1. How does a 10kW solar system work with batteries?

AC coupling has enabled the installation of solar battery storage in all the existing PV systems. This allows you to attach a battery to any property as it connects directly to the main power supply. With the batteries, you can use the stored solar power day and night without the need to buy energy from the grid. However, keep in mind that battery backup options are quite expensive and increase your payback period.

There are many options for installing batteries with a 10kW solar system on a single-phase connection. Certain batteries cannot be connected because they use a 5kW inverter to convert the AC power received from the solar inverter to DC power for batteries. While this doesn’t have any impact on the grid, some retailers still consider this storage inverter as inverter capacity. Still, other battery options can be installed just fine with a 10kW solar power system.

  1. Can you go off-grid with a 10kW solar system and batteries?
    Apart from location, angle of the solar panel arrays, daytime energy consumption, daily consumption, there is one more factor that determines the self-sufficiency of your 10kW solar system—battery storage capacity. You need to make sure that you can store enough energy to get you through 3-4 days of rainy weather, which is called ‘energy autonomy’. If your solar system is not large enough to charge your battery bank, then you will need a generator to go off-grid, which will further increase the overall cost of the system.

Assume that your 10kW solar system in Sydney is north-facing, unshaded with 10kWh of daily energy consumption and mostly daytime usage. Then, a battery with 30kWh of usable storage capacity will provide you with the primary ‘storm blackout protection’ or 3 days of energy independence. Likewise, a 40kWh of battery capacity would provide around 4 days of energy independence.

Hence, it is feasible for households with low electricity consumption to cut off from the grid with a 10kW solar system and batteries. There will be enough excess energy for the home to use either occasionally or regularly. Even if your daily average consumption increased to 15kWh per day, a 10kW solar system would still produce sufficient energy to meet your home’s energy demands. 

  1. Can you install a 10kW solar system on a single-phase connection?

You can achieve a 10kW solar power system on a single-phase connection either by installing an 8.2kW inverter or 2 single-phase inverters—which is far more expensive than a single 8.2kW inverter. Besides, you have to utilise the extra 5kW of potential export limited power to see the benefits. If you expect a regular base-load of around 5kW, then you should consider upgrading to a three-phase connection. Otherwise, 2 x 5kW single-phase inverters are the way to go. However, for most installations, an 8.2kW inverter provides sufficient power and is flexible in its design and cost-efficient. 

Before that you need to understand the effects of export limitation and whether it is a suitable solution for your particular situation. Additionally, having cleverly timed loads like an electric hot water system or excessive daytime usage will help you minimise or even eliminate the wasted power that the export limitation incurs. So, if carried out properly, the larger single-phase systems by controlling the export limitation could be a great, cost-effective alternative compared to the three-phase connection.

ConclusionWhile purchasing a 10kW solar system, it is important to consider your personal consumption. The 10kW solar power system particularly encourages more daytime energy usage, making it a perfect choice for those who have home-based businesses or who want to run air conditioning during the day or have a pool heater.

Author: Harsh Patel

Date: August 13, 2021


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