In a previous post I showed how I evaluated a basic 1.5kw system for my house in Victoria … But is it worth installing extra panels?
Basically the government supports domestic solar installations up to 5kw although the most support is for systems up to 1.5kw. The effect is that the cost per kw for upgrading above the basic systems is around $5000.
Here’s how I evaluated an upgrade for our house in a Melbourne Suburb.
- For each 1kw of solar panels we can expect to generate around 1300kw hours per year – that’s on average around 3.5 kw hours per day;
- If we go solar we will receive $0.66 for every kwhr we put back into the grid;
- The tariffs will be:
– $0.2625/kwhr peak times (7.00am – 11.00pm Monday to Friday)
– $0.1075/kwhr off peak (all times other than peak)
Evaluation
Weekdays (as we both work and the house is empty during the day) we should be able to put the full 3.5 kwhrs into the grid as the basic system will run any appliances being used.
Income 3.5kwhr @ $0.66 = $2.31
Benefit = $2.31 x 260 days
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= $600
Weekends on average we probably will only be able to put 3kwhr into the grid
Income 3kwhr @ $0.66 = $1.98
Saving 0.5kwhr @ $0.1075= $0.05
Benefit = ($1.98 + $0.05) x 104 days
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= $211
Total annual benefit is $811
Is it worth it?
If you had $5000 on term deposit it would now (March 2011) be returning 6% – that’s $300 a year, which would then be taxed. Alternatively if you put the cost on your mortgage that will mean that you are borrowing $5000 at a rate of around 8%. That’s costing around $400.
From these figures in Victoria it looks like for the basic system we could be around $400 better off. Not as good as the original installation, but still reasonable. The tariffs and buy back figures vary from state to state, so you will have to put your own figures in the evaluation.
If you’ve already decided that solar power is for you, this additional article about Types of Solar Panels may come handy.
This article was contributed by Brian Ashworth. Brian is a Chartered Civil Engineer with over 30 years experience in Water Engineering, who lives in Wyndham Vale, VIC. For a great collection of tips on building or renovating a house visit his blog A New House.
