Archive for May, 2009

The Sunshine Coast Environment Council’s 1000 Solar Roofs Project is rapidly proving a great success. With the support of the local newspaper, the Sunshine Coast Daily,  the number of people who have signed up for a solar system on their rooftop is fast approaching 700. See article Roof Solar Challenge at half way.

The 1000 Solar Roofs Project campaign only began less than a month ago – it shows what partnerships can achieve.

If you live in another part of Australia and are interested in setting up a similar campaign in your area, we’d love to hear from you.

Not only are these 1000 households saving on energy bills, they will be responsible for saving around 1.4 tonnes of CO2 each during every year over the next 25 years: a total of 35,000 tonnes.

The 1,000 solar roofs project on the Sunshine Coast has just received the next boost. The Sunshine Coast Daily has written about the solar bonus cost savings Ken and Helen from Caloundra have achieved.

An Energex spokesperson recently made a comment that the potential savings from PV which I had calculated were incorrect. After more investigation and help from industry representative I realised I had calculated the yearly output of a solar power system based on ideal conditions, rather than taking into account that there were additional losses.

What causes losses:

• The temperature of the panels
• Dirt on the panels
• Losses in the cabling
• Shadow
• An orientation that is not exactly true North

What Solar Bonus Cost Savings Can You Expect?

In the post about Feed-in Tariff and How You Benefit, I stated that you can expect a 1kW system to produce 2,000 kWh per year (on the Sunshine Coast). The losses actually reduce that by 20% to about 1,600 kWh per year.

Financially that means the minimum savings are not $340 as stated. Instead they are about $256. However, with the upcoming price increase of 14%, this jumps to $290.

What is the Maximum Possible?

The answer is that it depends on your usage of electricity. The theoretical maximum is $704. That is if you receive 44 cents for every kWh that the system produces (Origin pays 50 cents). In practical terms that is unachievable as you will always have some electrical appliance running (the fridge at the very least).

Assuming that you have a 5-star rated fridge that uses 360kWh per year (there are even 6-star rated fridges now that use as little as 250kWh per year), and assuming that you are not home during the day and turn off your stand-by appliances, you might be paid for 75% of the electricity the solar panels produce.

How much it is for you, no one can say. But this table shows the savings possibilities (at the prices coming in 1July):

Here is an indication of possible savings,

exporting 75% electricity output= $625 savings
exporting 50% electricity output= $546 savings
exporting 25% electricity output= $467 savings
exporting   0% electricity output= $388 savings

It assumes 1,600kWh production of the solar system per year. A payment of 44 cents for the electricity fed back to the grid and a cost of 17.67 cents (15.5 cents plus 14%) for power usage.

Credit of $105 in the last Quarter

In real life, Helen and Ken in Caloundra have put in solar power systems last year in June. Ken’s latest power bill has a $14 credit. Helen’s shows a credit of $105. With previous power bills for Ken of $129 (less $25 ambulance levy), he is $118 better off now (on a yearly basis that would be over $450).

Helen is a bit of a pioneers women (as her children call her). She has a windup torch that she uses at night. She takes in the solar lights from the garden and puts them in vases. So she makes a difference in every possibly way. With a bill (before solar power) of around $20 (with a pensioner’s discount), she is now $125 better off, which equates to $500 a year.

They both put in a solar hot water system in November. So their bills are further reduced by that, even though I would not be surprised if they opted for their cold outdoor rainwater showers a lot of the time anyway.

My Apology

My original calculations were incorrect. However, at no time did I aim to misrepresent any figures. Should anyone wish to cancel their order, we will refund any monies paid in full.

Thanks again to Scott from Voltmaster for advising the correct basis for calculating the savings. His website provides a further overview on Solar Bonus Cost Savings for different size systems.