Price Paradigms For Solar – November 2016
Remarkably, the price pressure on solar installations in Adelaide remains in a downward trajectory. This is surprising given the relative weakness of the 
Australian dollar. Solar panels and inverters are generally quoted by the manufacturers in US dollars at the importer / wholesaler level, so any weakening of the AUD is generally a sign the prices in solar components will need to rise. It would appear that given the fiercely competitive nature of the rooftop solar installation market in Adelaide, that the installer margins must be being squeezed in Q4 of 2016.
Large Scale Solar continues To Grow
ARENA, the Australian Renewable Energy Agency has survived the threat of ‘extinction’ by the coalition government and is investing in close to A$100,000,000 of solar farms, meaning a close to three fold increase in large scale solar power output for the nation or 700 megawatts of solar production. Not only does this continue to demonstrate solid support of the solar sector of the Australian renewable industry but will generate significant jobs growth and ongoing economic benefits to rural and outback Australia – particularly Queensland and N.S.W. in this latest round of announcements.
Solar Cell Development And The Physics Of The Photoelectric Effect
The rooftop solar panels that you see on roughly 10 percent of Adelaide homes all work on the same fundamental principle, regardless of their manufacturer or silicon ‘makeup’ of being either monocrystalline or polycrystalline in their constituent solar cells.
The underlying physics of how silicon based solar cells work is fascinating and is the result of the application of the ‘photoelectric effect’, originally discovered through experimentation by the German physicist Heinrich Hertz in the late 1800’s and later further developed by Albert Einstein. The fundamental principle discovered was that electrons, the basic ‘building blocks’ of electricity and electrical current, can be made to ‘flow’, thereby generating an electrical current, when light ‘particles’ fall onto a suitable material. In essence, a transformation of energy from light energy to electrical energy, as that which occurs in modern solar panels, is the result of this photoelectric effect. The physics and theoretical models that were developed to explain this effect are complex, but their application would make way for world changing technologies to be developed.
Further reading:
http://www.physics.org/article-questions.asp?id=51
https://en.wikipedia.org/wiki/Photoelectric_effect
Current Sizing Of Solar Systems In Adelaide – Factors To Consider
We have seen that many people in Adelaide are electing to install 5 kilowatt solar systems seemingly on the basis that solar installers are heavily promoting 5 
Kw systems as virtually a ‘default’ or ‘one size fits all’ size solar system. The question arises as to how should you approach how the question of determining the ‘correct’ sized solar power installation for your property, be it residential or possibly commercial?
The ‘conventional approach’ to solar system sizing is to work from an assumption that there is far less ‘sense’ in exporting solar electricity, that has been generated by your system, back to the power authorities, because the current ‘feed tariff’ of 6.8 cent per kilowatt hour payment is ‘minimal’ and is being reviewed, with view to being removed completely, on the basis of potentially opening up to ‘market forces’ the payment for solar electricity exported back to the S.A. grid. We would be very surprised to see any substantial increases offered for the South Australian feed in tariff moving into 2017.
So, because there is minimal financial ‘benefit’ in selling solar electricity to the grid, it makes most sense, financially speaking, to use the maximum amount of electricity a solar system produces, in your premises. So, it is obviously helpful to determine what the average, year round electricity consumption of your premises is during the daylight hours – the time when your solar system is generating solar power.
Depending on the type of electricity meter you have installed, one approach to measuring your electrical power consumption on a daily basis is to take a measurement of your electricity meter first thing in the morning and then later on in the late afternoon. You can then get an idea as to how much power you use during the hours that any newly installed solar system will produce power. It is optimal to do these measurements, ideally, during week days, when many occupants may be at work or school for example, meaning that less electrical appliances are run, and, on weekends, when most households tend to use more electricity. Again, this varies greatly from premises to premises. Once these figures are established you can work out what proportion the daytime electricity usage represents as a percentage of the total daily (meaning daytime and nighttime) usage. This can then be ‘extrapolated’ over the 4 billing periods electricity usage as shown on most electricity bills. It has been estimated, that, as a ‘rough’ rule of thumb, that most Adelaide homes use between 30 percent and 40 percent of their electricity consumption during daylight hours. Use this as a ‘benchmark’ when working out your individual power usage calculations.
Adelaide, South Australia – Solar System Average Daily Production Figures.
Once you have an idea as to what your average daily electricity usage is, the following table will be useful in determining what the corresponding sized solar panels system will be, to generate that amount of electrical power.
Solar System Size in Kilowatts Average Daily Power Generated
1 kilowatt solar system 4.2 KWh
1.5 kilowatt solar system 6.3 KWh
2 kilowatt solar system 8.4 KWh
3 kilowatt solar system 12.6 KWh
4 kilowatt solar system 16.8 KWh
5 kilowatt solar system 21.0 KWh
6 kilowatt solar system 25.2 KWh
10 kilowatt solar system 42 KWh
Not All Solar Systems And Installations Are The Same
It is very important to understand that the above figures (system size v power output) should be taken as a guide only. There are a huge number of factors that can make a difference between solar system ‘a’ of 1 kilowatts being installed in Adelaide ‘property one’ versus solar system ‘b’ also of 1 kilowatts being installed in another Adelaide property ‘b’. These factors include:
- Orientation of the solar panels. Whilst a north facing solar panels installation may be optimal (in some instances), obviously not everyone’s roof has that orientation and it may be that a compromise is needed in the installation of the system. This in itself can lead to losses in power generated by the system.
- Solar Panel Tilt. The ‘average’, if there is such a thing, pitch of most houses roofs is 22.5 degrees. Obviously this varies. Optimally we would want our solar panels in Adelaide to have a tilt of around 30 to 35 degrees to generate the maximum electrical output. In reality, for roof pitches of 22.5 degrees the losses are typical around 2- 4 percent from a 35 degree pitch.
- System Efficiency. Any electrical system inevitably has system losses and solar systems are no exception. Losses in solar system output can be attributed to the transmission cables connecting the solar panels to the solar inverter, the inverter efficiency, the solar panel performance under hot summer temperatures (solar panels output less electrical power at high ambient temperatures) and the quality of the panels themselves. As solar panels age, they output less electrical power also.
Summary.
So, as discussed above, it can make sense to ‘tailor’ the solar system size to your ‘average’ daily electrical usage. In our view, any Adelaide solar installer worth their salt is going to be able to competently take you through these steps and present a ‘logical’ case for recommending a certain sized solar system. If they do not, or you are unclear, do more research or get a second or third opinion. Solar is a long term investment and procuring the right, high quality system by a long established (preferably Adelaide based, in our opinion) solar installer, with backup of the inverter and solar panels from strong Australian distributors is important when deciding to go solar.