6 kW and 6.6 kW System

Q Cells expands premium range in Australia – pv magazine Australia

This article is about both 6 kW and 6.6 kW solar systems. 6.6kW solar systems are very popular amongst Australian homes. They generate 32 kWh of electricity each day, enough for a family of 4. 6.6 kW systems are the most bang for your buck, giving a great return on your investment. They provide the most amount of STC’s, you can get in a single phase home.

Why get a 6.6 kW system? #

Most people opt for a 5-kw system with a 5-kw inverter, as that is the maximum you can install for a single-phase household. However, calculations have shown it better value to install 6.6 kw of solar panels along with a 5-kw inverter. This is allowed as according to the Clean Energy Council guidelines; you are able to oversize your system by 133% which amounts to 6.6 kw (5 kW x 133% = 6.6kW).

Why you should get a 5kW inverter #

You may be wondering why you should get a 5 kW inverter. It would make sense to get an inverter with a higher capacity. 5 kW inverters are generally cheaper than 6 kW or higher. Most of the time, panels would not perform 100% of their rating. Solar panels may lose 10% of their performance due to temperature or dirt/grime. It is likely that by using a 5kW inverter, you will ensure the inverter is working at its designed performance level. 5 kW inverters are also the maximum capacity some Network Service Providers allow you to connect to the grid.

Click this article here to learn about choosing a quality inverter.

How many panels in a 6kW and 6.6 kW solar system? How much area required? #

An 6 kW solar system using 300 watt (W) to 330W modules would require 18-20 panels.

For a 6.6 kW solar system using 300 watt (W) to 330W modules would require 20-22 panels.

Each module measures out to 1.6 m2. For a 6 kW solar system, you would require 28.8-32m2 of roof space. This area may change depending on how your roof is laid out. Also, whether or not you may need to use additional tilt frames.

A 6.6 kW solar system, you would require 32-35.2m2 of roof space.

We have this article to know how panels may impact your roof.

How much does a 6 Kw and 6.6 solar system cost? #

In South Australia, the average retail price of a standard solar 6 kW and 6.6 kW PV system installation is $0.86 per watt, after government solar rebates. This means that, the average cost of a 6 kW solar system is $5,160. The average cost of a 6.6 kW solar system is $5,676.

Solar systems have been getting cheaper over the years. We have seen that prices of solar systems do vary widely. Cost-competitive 6kW and 6.6kW solar PV systems are cheap but have low-end components. Premium options are pricier but use reliable and long-lasting products.

How much energy will a 6-kW and 6.6-kW solar system produce? #

The power output of a 6-kW and 6.6-kW power system varies. Factors include:

  • Temperature of local area
  • Orientation and tilt angle
  • Shade cast by obstructions
  • The performance efficiency of components

The amount of sunshine is what determines a system’s output. In Adelaide we would expect 4.84 sun hours daily. Multiply 4.84 by system size to get a rough estimate of system performance. We would expect a 6 kW system to generate 29.04 kW daily. A 6.6 kW system is expected to generate 31.94 kW daily.

To get a more conservative estimate, multiply by 0.75 to account for performance efficiency. Note that energy yields are not accounting for seasonal changes. Energy generated will be higher in the summer and lower in the winter.

Batteries with a 6-kW and 6.6-kW solar system? #

To install batteries with your solar PV system, we recommend a minimum of installing a 5kW system. This would make the most out of a battery system. A system of that size would generate sufficient energy to consider storing. We highly recommend installing a battery with a 6 kW and 6.6 kW system. Take advantage of storing excess generated energy and maximize your self-consumption, don’t have to rely on drawing electricity from the grid.

Click here to learn more about batteries.

How long is the payback period on a 6kW and 6.6kW solar system? #

Payback period is the amount of time it takes for the system to pay itself off. The payback period takes into account energy bill savings and feed-in tariff credits.  

Self-consumption is how much solar energy you use. Keep in mind you unable to self-consume when your panels are not generating solar power, this would be when there is no sunlight hitting your modules. You are able to maximize your self-consumption with the use of a battery system.

For a 6 kW, assuming you have 30% self-consumption, you will save $1519.68 annually. This is also assuming the remaining generated power goes towards a feed-in tariff. The estimated pay-back period would be 3.39 years.

For a 6 kW, assuming you have 50% self-consumption, you will save $2532.77 annually. This is also assuming the remaining generated power goes towards a feed-in tariff. The estimated pay-back period would be 2.04 years.

Assuming you have 30% self-consumption you will save $1671.63 annually, for a 6.6 kW system. This is also assuming the remaining generated power goes towards a feed-in tariff. The estimated pay-back period would be 3.39 years.

Assuming you have 50% self-consumption you will save $2786.05 annually, for a 6.6 kW system. This is also assuming the remaining generated power goes towards a feed-in tariff. The estimated pay-back period would be 2.04 years.

Click this article if you want to learn how to calculate pay-back period.

Compare Different System Size #

What sized system is right for you? (assuming you are located in Adelaide)

1.5 kW3 kW5 kW6.6 kW8 kW10 kW
$3482$4050$4800$5,676$7,360$9,900
5 panels 8m2 of space required10 panels 16m2 of space required16-17 panels 26-27m2 of space required20-22 panels 32-35m2 of space required25-27 panels 40-43m2 of space required31-34 panels 49-54m2 of space required
7.26 kW daily14.52 kW daily24.2 kW daily31.94 kW daily38.72 kW daily48.40 kW daily
5.5-7.16 years payback3.19-4.17 years payback2.27-3.79 years payback2.04-3.39 years payback2.18-3.63 years payback2.35-3.91 years payback
$486-$533 annual savings$972-$1266 annual savings$1266-$2111 annual savings$1671-$2786 annual savings$2026-3377 annual savings$2532-$4221 annual savings
Suitable for small households with electricity budget of $120 per bill cycle.Suitable for small working families with electricity budget of $220 or more per cycleSuitable for medium to large households using larger amounts of electricity, a budget of $350 or more per cycleSuitable for medium to large households using larger amounts of electricity, a budget of $450 or more per cycleSuitable for large households with an electricity budget of $500 or more per cycle.Suitable for large households using 20kW/day and an electricity budget of $700 or more per bill cycle.