climateXchange

I've just started reading a website in Australia about solar power for my home, which I've been considering for some time. I think the exceptional last quarter power bill has helped push my hand, now I'm just wondering about the outlay. But, having spent an hour or so reading through the http://www.solarshop.com.au website I note the plethora of different solar panel technologies on offer. Does anyone have any recent, practical experience of which type of solar panel they chose for their home in Canberra? I've no doubt we get lots of sunshine in Canberra, even on the coolest days, however I find it not terribly helpful to hear that some panels are less efficient with high heat – what's considered a high temperature for a rooftop? Having once worked on a tin roof in QLD I can say a roof gets pretty hot, and with dark tiles in addition I'd imagine it would be upward of 35 degrees C on a really hot day with all that heat absorption? 

Any anecdotal experiences welcomed!

That's a fair question and I have considered it previously, I also read your post on the issue of green power. 

I think it's a very good thing to have the green power option and noted your point about the economies to be achieved when more people support green power over conventional energy – the more people buy it, the more our demand stimulates markets for large scale production of these sources of energy eg., large scale wind and solar farms would seem to me a great way to go if it's possible. Although, I'm also aware the ACT Government seems to be doubtful of how much more wind power can be generated in our region due to limited availability of sites?

I've also scanned the list of green power sources that are used. I recognise some is highly sustainable e.g., solar and wind generated. Some, however, appears to be sourced from slightly less sustainable alternatives eg., methane which is produced from outgassing from existing rubbish dumps. If I've read those lists correctly, the latter is a second best option. Ideally, you would choose to use methane produced by landfills for energy because it's better than having it add to the atmospheric GHGs, but it would be even better if we were producing less waste going into landfill in the first place. Hence, I'd view this source as transitionary to a really clean form of energy production. 

But, as we all know, energy companies are in the business of selling us products. No disrespect to ACTEWAGL which is a fine company that has its CSR down pat, but they're in the business of making a profit. I'm going to hazard there may be an inbuilt interest in keeping the alternative energy sources used for green power generation and on-selling to consumers diverse as it gives them the 'green' bill of health while also enabling flexibility in their sourcing of the energy according to what's cost efficient and available…but then I'm not 100% assured it's 'just' solar or wind. It can't be. 

Therefore, I'd prefer to be producing my own solar power if I could. I'd know my money was purchasing an asset that produced a type of energy that I support and, in the process, supporting an industry I believe Australia is very well placed to develop. 

But, that's just my preference. In reality, the green power option will suit many people who may find solar panels cost prohibitive or unviable for their housing circumstances. 

Thanks Marea, in particular for sharing the info on the energy generated. I have rung the solarshop people about getting a quote, so hopefully they'll be able to advise on the options for me. The variation between the seasons isn't a surprise, I'd guess the ideal is an average based on best conditions, although in my case it will be interesting to see if this is an issue as there's no shadow on my roof at any time apart from that unavoidable in the sky eg., cloudy days. It's a shame that BP moved off-shore, but I'm not surprised. We're simply not a big enough market to support the manufacture. I suspect China will be the main competitor in this area to produce and export, even if the technologies are developed in countries like ours? Unavoidable really, but let's see how much an install will cost!

jubilee said:

Hi I too am considering solar panels for my roof in south Canberra. I am wondering what size system to get? I was thinking 5 kw? Has anyone had a problem with birds dirtying the panels or dust blocking them? Do you have to go on the roof every few months and clean them?

Will the cost go down any time soon?

To fit 5KW you would have to have a fairly large bit of north-facing roof. My more modest roof space is half taken up with a 1.8KW system and solar hot water occupies a chunk of the rest. I could really only get about 3kW if I filled the rest. It rains often enough to keep them clean. I hardly ever clean them manually but the people I bought my panels from (Armada Solar) check that the output is in the range they would expect and clean them occasionally. This was included in the purchase price and most likely other installers make similar offers. 

One time I thought they looked pretty dusty so I did an experiment. I gave them a hose down in the middle of a cloudless summer day so the intensity and angle of the sun would not change much over the time of the experiment. I noted their output on the inverter, hosed them very thoroughly, quickly noted the output again, then waited for them to have fully dried out, warmed up, and noted output again. The first and third reading were virtually the same-a bit of dust was not reducing output. On the other hand I was getting about 10% more output when the panels were still cool from being hosed, the second reading. This is normal and expected. Output of all PVs declines as temperature rises. A specification on all panels is a temperature coefficient-some types are more sensitive than others but my impression is that generally there is not variation. IE how much does output go down for a degree of temperature rise. One of the reasons PVs work well in Canberra is that we have a lot of sunny but cool days in winter. The reduction in total sun in winter is partly compensated by the reduction in temperature so overall the electricity output does not go down as much as you might expect in winter. 

Panels on roofs are usual on a frame that spaces them out a bit from the roof so that air can circulate behind and wind and convection can cool them. 

I think panel prices are expected to continue to drop but only by smaller percentages (say 10%), not suddenly halving in price. On the other hand the feed-in tariff is periodically reviewed. It went down from 50.05c to 45.7c this year (now at 45.7c till mid 2012) in recognition that the tariff did not need to be as high to make panels financially attractive. A body called the ICRC has the job of doing an economic analysis and recommending an ACT tariff that is sufficient to be attractive without being over the top. Similarly the Federal Solar Credits incentive phases out gradually over the next few years-still 5x in the next financial year but then 4x, 3x etc. in subsequent years. The idea of both is to make solar just as attractive now as later, even though prices may be higher now, so people do it now rather than always putting it off till next year. 

I hope that helps!

marea said:

Peter, in my post earlier in this thread I mentioned that my 1.05kW system generated an average of 3.14kWh per day in the winter period June-September this year compared to an average of 5.13kWh per day in the summer period last December-March. Did you find a similar significant drop this winter with all the rain?

jul-oct2010 609KWh

Apr-jul 2010 535 kWh

jan-apr 2010 712 kWh increased from 1.44kW to 1.8KW during this period (10 vs. 8 180W panels)

oct-jan 2010 634 kWh

jul-oct2009 509 kWh

Apr-jul 2009 366kWh

Jan-Apr 2009 626 kWh

April to July saw a 46% increase with 25% increase in panels but jul-Oct saw only 20% increase. 

April to October this year was an average of 6.26KWh/day or 3.48kWh/day/kw for the two winter quarters.  That's probably consistent with your 3.14kWh/day through the middle of winter.