6kW solar power systems are a better investment than ever due to a the falling price of solar power systems, and the steadily rising price of electricity. This article covers the price ranges, yields (in kWh), and economic returns that a home or business can expect with a typical 6kW solar PV system.
Price range for 6kW solar PV systems
The price of solar PV (photovoltaics) has fallen dramatically across the globe since 2009, thanks mainly to government incentive schemes and a huge increase in the manufacture of solar panels in China in the past few years. The resulting competition between manufacturers as well as between system installers has managed to drive down the retail price of solar PV systems at a rate of around 45% per year. This is major news, and it may not be too much to say that a solar revolution is taking place–both internationally and in Australia.
In Australia, the average retail price of a standard solar PV system installation of mid-range quality is just above $2 per watt, after federal government solar rebates are taken into account. This means that at the time of writing, the cost of such a 6kW solar system is just around $13,000–around a quarter of what it would have been in 4 years ago.
The price of solar systems do, however, vary widely in the market. A more cost-competitive 6kW solar PV systems consisting of cheaper, low-end products will be cost less, while premium offerings will generally be pricier.
Normal output for 6kW solar systems
Depending on a number of factors, the actual power output of a 6kW solar power system will vary. These variables include:
-Geographical location of the system and the expected daily and annual solar irradiation and cloud cover levels there
-Actual operating temperature of the panels
-Whether solar panel array capacity is accurately matched to inverter capacity
-The performance of the individual components–i.e. the panels and the inverter
As mentioned above, depending on where the system is located, it will receive different amounts of solar irradiation throughout each day and each year. The amount of sunshine falling on a solar system’s solar panels directly affects the system’s output. A solar system which is facing the right direction (i.e. north) in Australia can expect to receive around an annual average of 4 hours of ‘peak sun’ (peak sun hours, or PSH) per day, although Tasmania receives less than this, and Broome, WA receives more. This is only the daily average across the course of the year; it is important to keep in mind that the sun shines for more hours in the summer months and fewer in the winter.
For example, a perfectly efficient 6kW solar system in Sydney would produce about (3PSH x 6kW =) 18kWh of power on a day in the middle of winter, whereas in the summer output from the same 6kW solar PV system would be around (5PSH x 6kW =) 30kWh. (Figures are approximate only.)
6kW solar system financial returns
The financial returns from a 6kW solar PV installation are mainly dependent on the presence or absence of a Solar Feed-in Tariff to the owner/operator of the system. Solar Feed-in Tariff schemes pay solar system owners a premium for each kWh of power that they send to the electricity grid. Financial payback accordingly depends not only on the total output of the system, but also how that power is utilised by the occupants in light of whether or not a Solar Feed-in Tariff is being applied.
There are essentially 3 situations that owners of grid-connect solar systems might find themselves in regarding Solar Feed-in Tariff incentives:
1. They have acces to a Solar Feed-in Tariff, which encourage solar system users to export power to the grid at rates that vary from state to state, but which are above the retail electricity rate–that is, a premium.
2. They have access to a 1-for-1 ‘Solar Buyback’ scheme in which they are paid an amount equivalent to their retail electricity rate for every unit of solar power that they feed into the grid. People in this category should simply try to reduce their power consumption as much as possible, as they can neither gain nor lose by either exporting or self-consuming their solar p0wer.
3. No mandatory solar feed-in incentive scheme exists, or the rate offered is nominal–e.g. 7c/kWh. In this situation system owners should avoid exporting their solar power to the grid, and instead time their electricity usage to ensure that they are ‘self-consuming’ their solar power–using more electricity when the sun is shining, and less when it is not.
Download a 6kW Solar Power System ROI Calculator
How to use the calculator*:
1. Download the Solar Choice 6kW Solar System ROI calculator (Excel spreadsheet file)
2. Request a Solar Quote Comparison of the solar system installers in your area to obtain system prices,
3. Visit SwitchWise or a similar site to find the best deal on electricity,
4. Alter the variables in the light blue boxes (system size, system price, etc) in column B to calculate system Return on Investment (ROI).
(You may also open the file in Google Docs if you have a Google account.)
*Calculator outputs are indicative only–please keep in mind that electricity rates and Feed-in Tariff rates may change over time.
© 2012 Solar Choice Pty Ltd
He holds a master's degree in Environmental Management from UNSW, and a bachelor's degree in Philosophy from Bridgewater State University in his native Massachusetts.