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Solar panels. Do we? Don't we?


tonyhSun, 01/04/2018 - 2:16pm

This is about solar photo voltaic (pv) systems which you install to generate electricity for your own use.

I am not an expert on pv systems. I don’t even have one at this moment. But we are moving down this path and I‘m keen to learn from others on this matter.

Our household is a fairly small user of power as our water is solar heated and we use wood for heating in winter. This means an investment by us in pv is hard to justify on pure economic grounds although the payback would vary according to the type of installation we choose.

Our three main options seem to be:

1.  To go off the grid completely. It’s safe to say power prices will continue to rise. Feed-in tariffs on offer by the electrical retailers for any extra power we generate are poor. (The best on offer here today is 12.8ȼ per kWh – see the Energy Watch website.)

Moreover, as the total amount of energy being generated from rooftop installations rises, the grid is becoming oversupplied. The energy companies will turn off feed-in supplies when it suits them.

However, we don’t intend to go this way. Our roof faces east-west and we have shading problems. That aside, I doubt that we could generate and store sufficient power here to cover all events including equipment failure and the occasional long periods with little or no sun.

2.  To stay on the grid with modest roof-top generation. The system would meet all but our highest power needs during sunlight hours. Any surplus would be fed back into the grid to partially offset the cost of usage in the ‘darker’ times of the day.

3.  Roof top generation with battery backup. As in 2, but with the added facility of storing surplus energy in a battery bank. The bank supplies power when the sun is absent and anything then left over goes into the grid.

The last few years have seen an extraordinary decline in the costs of solar panels. In 1977 they cost about $77 per watt of output. In 2017 they cost about $0.64 per watt. That’s a 99.2% drop in 40 years. And a further 40% reduction of all solar equipment is forecast over the next 4 years.

On a national scale, wind and solar generation is on the verge of becoming cheaper than energy from coal and gas fired power. (Did you know that 48% of grid electricity costs are for the poles and wires that carry the power?)

So, for our personal needs, we have been asking:

Why would we do this at all knowing the financial returns will be small?

We’ll have the satisfaction of knowing that we are using the best and cheapest resource we have (the sun on our roof) to moderate our power bills. Also we’ll help to force efficiencies on greedy supply companies. And we’ll ease the carbon pollution problem. We think these are reasons enough.

When should we do it, as it’s clear that solar installation prices will drop further?

The market is currently flooded with ‘service providers’. Every Tom, Dick and Harry is out there selling solar. This promotes competitive pricing, giving us choice and the power to negotiate.

Eventually the wheat will be separated from the chaff and only a few major providers will be left standing. They will be like the ‘big four’ banks and the electrical service providers of today. They will slice the market up, dominate service and control prices. The component costs will be at all-time lows, but we can be pretty sure the full financial benefits won’t flow down to us.

So, we feel the time for us is now.

 (As an aside, there may currently be many providers, but I suggest extreme caution. There are a lot of cowboys who know even less than I do about the pv systems. Seek out several testimonials, check for feedback on the web, and ask around.)

What kind of system should we put in?

This is very much an individual decision depending on needs and resources.

As I said, we won’t go off the grid in the near future. Even a small shadow on a panel can shut it down. However, there are some clever solutions to shading which involve the use of fancy gadgets (micro inverters) on each solar panel. Each panel works independently. The system can still supply power even when some panels are shaded.  

Nevertheless, the breakdown of an important component (i.e. the batteries or an inverter) could leave us in the dark for some time if we go off the grid.

We have seriously looked at a grid-linked battery backup system. Everyone is out to sell sexy Tesla Powerwalls with a 10-year warranty. Impressive lithium ion technology. However, Tesla only warrants a 70% output after 10 years and makes no promise of life after that. To spend $12k on a Tesla, or any other battery, only then to throw it in the bin is hard to accept.  That’s $1200 a year write-off. And an even less attractive option when we know that the carbon cost of making batteries is currently much higher than the environmental gains from using them.

There are other batteries with older technology that deserve consideration. They enjoy much longer lives but with less convenience.

The cost of solar panels has dropped so dramatically mainly because of economies of scale and improved manufacturing methods rather than through technology improvements. With batteries it’s different. Pv storage technology for home use is in its infancy. There is little doubt that battery and inverter technology will improve in leaps and bounds over the next few years.

So, as to “What?” I think we’ll go with option 2 above and watch how battery storage evolves.

Should we do it ourselves? It’s not that difficult for a practical person. But the retailers have access to much cheaper equipment, unless you’re prepared to import directly from China. And we would rather go boating. Answer yet undecided!

The following link takes you to a website which is quite useful. The author of the site is making money from it but the info he provides has helped me to put my thoughts in order:


Meanwhile, I’m interested in sharing ideas with others in the village who have gone down this path or are thinking of doing so. Please feel free to add your comments to this article or to contact me at tonyhann7@bigpond.com.

Tony Hann

Additional notes. The website isn't accepting comments on articles at the moment so I'm adding some notes here.

I have discovered:
There are lithium ion batteries that are smaller, more powerful and cheaper than the Tesla battery. The LG Chem battery is an example, although LG only guarantee 60% capacity after 10 years compared with 70% for the Tesla. Still it is very difficult to justify buying batteries as a financial investment.
There are solar panels which are less susceptible to shading because their cells are connected together in smaller groups on each panel. The REC Twinpeak is one brand name.
There is an alternative to having a microinverter on each solar panelto reduce the effects of shading. It's called a solar optimiser. See the Solarquotes website for a between the two.
Tony Hann



comment(s): 3


Hi Lorraine. Yes I can tell you what I know if you would like to give me a call. Tony Hann 4997 3583

Does anyone have recommendations on solar installers in the area?

I suggested in the article that,"Eventually the wheat will be separated from the chaff and only a few major providers will be left standing."
Today I tried to contact Solar Australia in Newcastle to be told that they had gone into administration since we got a quote from them just before Easter!
Apparently over 500 Australian solar energy companies have folded or shut up shop since 2011.
So I got it wrong. The separation of wheat and chaff has been going on for a long time. The choice of supplier is shrinking daily. Tony Hann

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