Solar Power for the House

In early December I contacted one of the better known solar power providers and was told over the telephone that because of the surrounding trees my house was not suitable for solar panels.  This opinion was based on satellite images of the house that the man was viewing from the comfort of his desk.  At that point I thought that it was the end of the matter though I was greatly disappointed with the result.

But after a few days of thinking about it I concluded that such an important matter warranted a visit to the house by someone who was willing to discuss the issue while in plain sight of the setting.

I went back to the internet and selected a firm named Solargain.  While looking at the Solargain web site a there appeared a live chat popup asking if the person could be of help.  We exchanged messages, where I answered various questions.  In this exchange I specifically stated that I was less interested in a short payback period on the investment and more interested in making use of solar energy - as long as it was not impractical to the point of being absurd.  In our first telephone conversation he immediately described the roof of the house, its orientation, outbuildings, surrounding  trees, etc. Using software that provided him satellite photos of sun shading on the roof at various times of the day and different seasons of the year he surprised me by stating that it might be feasible.  The result  was a visit by Jeremy Lemieux on 3 January to discuss the matter.  In fact he had done his homework and arrived with the photo of a proposal.

A total of 22 panels were installed, 11 at each of the locations in this photo (Note tree at right)

Half of the panels were to be placed on the steep part of the roof, ideal for gathering sunlight from the east.  The other half were to be on the flatter verandah roof, better positioned to gather sunlight in the middle of the day and early afternoon.  Note that the house is orientated almost exactly north-south, with the sun rising from the right side of the photo (E), arching over the top of the photo (N), and setting on the left side of the photo (W).  The panels are cleverly positioned at the south end of the roofs, minimizing the shading from the trees to the north of the house, particularly in the winter.  This man had done his work well.

There was the important proviso that I lop the top of the Queensland box tree next to the east side of the verandah, to which I agreed.

The current arrangement in Western Australia is that solar power not used by the house is sold to the grid.  This is great from the ecological perspective but financially it is not so good because selling to the grid yields only about 25% of the cost of purchasing from the grid.   Most of the power would be generated during the first half of the day when I am least using electric power, so it made sense to me to install batteries so that I could store the excess power for my own use rather than sell it at a discounted price.

Jeremy stated that the battery market is currently in a flux, with the technology and pricing changing fast.  His strong advice was to wait until the technology settled down and prices dropped, as they inevitably will.  "OK", I replied, "So can you install a battery-ready inverter?"  Indeed he could.  This was big.  Inverters are expensive items and many existing solar installation will require the expensive replacement of their inverters in order to accommodate batteries.  Also, Jeremy noted that my house has 3-phase power )from the days when I was running a big electric welder), so I would require a 3-phase inverter.

I eventually accepted Option 2:

22 x Q-CELLS Q.PLUS 280 G4 
6.16 kW Solar Power System
1 x Fronius Symo Hybrid 5.0 3 Phase

Accessories
1 x Fronius 3P Smart Meter
1 x 4 FREE PANELS WITH YOUR PV
SYSTEM
Discounted Purchase Price:
Full Purchase Price:
$8,290.00 incl GST
Less Assignment of STCS:
$4,284.00 GST n/a
$12,574.00 incl GST

The Q-Cell panels are German engineered and manufactured in Korea, China, and Malaysia.  R&D is out of Korea, China, Malaysia.  They have a 12-year manufacturing warranty and a 25-year performance warranty.
 
The Fronius inverter is designed and manufactured in Germany.  Its normal 5 year manufacturing warranty was extended to 10 in a special offer.

Note the hefty STCS discount, provided by the government at about $700 per KW.  That subsidy is what makes the proposition feasible for me, and why solar systems are being installed in WA at a phenomenal rate.  (see http://www.abc.net.au/news/2017-01-31/solar-power-embraced-by-west-australians-at-record-rate/8227194)

The net cost to me was $8290.  Investing that money at a generous 5% given this era of low interest rates would yield me $414.50 pa before taxes.  I figure if I can save that much or more in reduced electricity bills then the investment will be worthwhile.  There is another factor.  Electricity prices have been rising steeply on the other side of Australia and are forecast to rise by 7% pa in WA for the next two years.

Solargain has provided the following output predictions from the system:








As expected, output will sag during the Australian winter period of May-Aug.  I accept that these figures have been provided in all honesty given that the company has been confident enough to put it in writing.  Solargain is a large company that has been very careful about fulfilling its promises - that's how it got to be so big.  Time will tell.

The installation was made by two technicians, Clinton and his offsider (Aussie term for assistant).  The arrived at 8 AM on 13 March and had the installation completed by 1 PM, which amazed me, given that there was some serious wiring work to be done and many panels to install.  I asked how the panels had been installed on the metal roof (worries of leaks at the back of my mind), and Clint told me that the panel support frames are held down by the same screws that hold the roof down, with extra sealant.  Very clever.

The system has a dedicated circuit with the result that the main electrical panel of the house is crammed to capacity.  It was a board set up when the house was built in 1950 and now it has to cope with RCD's instead off fuses, 3-phase power, dedicated circuits for hot water, stove, reverse cycle air conditioning, and now the solar system.

There is one remaining item to resolve.  The web Fronius (inverter) web page was providing inaccurate dates and outputs.  Technicians visited while I was away with the result that the web site now provides accurate output information but no history information because it is receiving no data from my inverter.  I will persist to have this fixed.

Example

This morning at 9.55 AM the situation was as follows:

3.686 kw coming in from the solar panels,
3.134 kw (85%) of that power being sold to the grid
0.552 kw (15%) used by my house

I then started a load of washing in the machine.  This would generate a load not just by the machine but more importantly by the avaricious electric stored hot water system.

At 10.00 AM the situation was as follows:

3.727 kw coming in from the panels (incoming power increased due to rising sun)
4.310 kw used by my house (100% of the solar panel output plus input from the grid)
0.560 kw being purchased from the grid.

Without the capacity to store power, washing clothes at night would be totally at the expense of power from the grid.

I expect to use a similar tactic for running the air conditioners (for cooling or heating) during the day as much as possible.