Solar Power advice in Melbourne « Alternative Technology Assn Forums

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Solar Power advice in Melbourne

(17 posts) (11 voices)

Started 10 years ago by muttiah
Latest reply from philbytee

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muttiah
Member

Hi all,
I'm just starting to look into Solar Panels for my house and would love some advice.
We're going to be in our house for many years and want to get solar panels to reduce our electricity bills (they are about $380 per quarter), and, if possible, make some money back in the future.
- We use about 16.5KwH per day.
- We live in Melbourne
- We have small kids at kinder and during most days, there's no one home
- Our roof is pitched and faces East and West
- We are looking at 2kw or 3kw systems
- We will connect it to the grid
- We have a smart meter that will need reconfiguring for solar

We have got three quotes so far:
- AGL 3.0KW use 12 * EE-250w panels
- Energy Matters 3.185KW use 13 * REC245PE-BLK panels
- NU Energy 3.12KW use 12 * SL260CE-48M panels

Does anyone have any experience with any of these retailers or panels?
Which side of the roof should we install on?
Should we opt for Gross or Net Feed In? (Do we have a choice in VIC?)
What else should we be aware of?

Thanks,
Josh!

Posted Thursday 19 Apr 2012 @ 12:51:24 am from IP #
hamish05
Member

Josh,I don’t have any experience with any of the company’s mentioned in your question.

I always think that for anyone that has not had any exposure to the PV industry or product, it’s advisable they download the “Clean Energy Council Consumer Guide” and familiarise themselves with the advice and suggestions contained therein.

The doc can be downloaded from.....
http://www.solaraccreditation.com.au/consumers/consumerguide.html

Good luck with your project.

Posted Thursday 19 Apr 2012 @ 5:41:26 am from IP #
dlvb19
Member

Hi Josh,

As far as product goes - go with the REC panels and SMA inverter if thats still what EnergyMatters is pairing it with.

REC won some award recently (2011) for top solar in world in terms of lasting efficiency (look it up, dont believe me as im a little fuzzy on the details). FYI panels degrade as they age and end up outputting only about 80%of what they originally did after 20yrs which is what I mean by lasting efficiency.
Other reason to get REC is they have lowest embodied energy of any solar panel. It takes approx 1 year of operation in Melb to have produced as much energy as was used to construct the panel. Most other panels take 6-10 yrs (again you should look this up yourself). If your at all concerned with sustainability and AGW this should be a fantastic selling point.

On another note EM **appears** to be doing quite well and probably wont go into receivership anytime soon as many other solar companies have. Although having said that AGL most certainly wont go bust anytime soon so they win for reliability.

Also I strongly reccomend SMA as they are German (cant guarantee they are built there though) company and have received many accolades for reliability which is KEY! Efficiency is stat number 2 to look at however they usually only differ by 1-3%. I personally would rather trade those few % for peace of mind.

And as always: Guarantee is king! If the manufacturer wont back it for 10 yrs but say it will last that long they are probably talking shit - which salesmen are consummate at.

Hope my quasi literate word salad has enlightened somewhat. Good luck

Posted Thursday 19 Apr 2012 @ 7:32:28 am from IP #
peter69_56
Member

In Vic you dont have a choice, its Net feed in, you get paid on what you don't use in your home.

My system is 3kw and we use 20kWh daily average
period 8/11-11/11
1583 Power in
1087 Production
629 Exported out

period 11/11 - 2/12
1163 Power in
1416 Production
732 Exported out

As you can see we are making the same as what we buy in, and export about half what we make

Hope this helps

Posted Thursday 19 Apr 2012 @ 1:27:34 pm from IP #
sunbeam
Member

Can anyone say how much efficiency will be lost by installing on east/west facing roof? Do you have any overshading in any season? In my situation I never realized a narrow conifer 2 houses away would shade part of my panels in July/August for about an hour midmorning. The output is then noticeably reduced.

If the production loss due to poor placement is substantial, it may be more effective to spend the money on reducing your existing electricity usage, although (in my experience) once people spend money on pv they tend to become energy misers anyway.LOL.

It would be very disheartening to install a system only to see it perform badly. A decent supplier should advise you as to whether it worth proceeding before you sign on the dotted line.

Posted Thursday 19 Apr 2012 @ 10:53:36 pm from IP #
alfresco24
Member

Muttiah, I hesitate offering recommendations about individual companies however the 3 companies you mention are among the top 5 or so operators in Oz. In Melbourne you may also give Solarshop a try. Other people here may have good things to say about other suppliers as well.
The Power quoted by suppliers is the maximum DC Panel Power, whereas the maximum AC Output Power is much less (losing >10% in the panel wiring, switching and inverter losses) and of course the power only peaks for a short time around the middle of the day. During summer the panels also lose a bit more power due to heat derating.
The East-West position is not ideal but better than nothing - provided there is no additional shading where the panels would be installed.
A 3kw system facing North at a 25 degree angle would generate approx 4,485kWh over a year, an average of 12.3kWh a day.
The same system facing 90' East would generate approx 3,649kWh
And facing 270' West would generate approx 3,717kWh
You can do these number yourself at http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/
Energy Matters also has a nifty app for the iPhone/iPad called SolarAnalyser that does some calc's for you as well, but I find it a bit clumsy.
In any case you cant rely on these tools to be perfectly accurate but they do help you examine variables and scenarios in the same circumstances.
Whether you go ahead or not the first thing to do is get rid of all the standby power that you can in your home. It costs you heaps especially when you waste Solar PV on it.

Posted Friday 20 Apr 2012 @ 1:54:35 am from IP #
TonyT
Member

Some solar insolation data with links to the source websites are provided at

http://www.ata.org.au/forums/topic/3253#post-26134

Analysis of energy measurements collected for our house over the last 12 months shows:

(1) 1,300kWh/yr which is 2/3 of the heat energy used by the hot water system is lost through the insulation that surrounds the 300 litre tank. With instant heating we would need only 1/3 of the heat energy.

(2) The old house fridge used 2000kWh per year. For $1600 we bought a new fridge that should use only 600kWh per year.

(3) Used only to store drinks, the small gas/electric fridge in the hot caravan used 1200kWh/yr ($270/yr) of electricity to keep a few bottles and cans cold. Better to stop that fridge and buy more drinks !

(4) About half of the energy was used to keep the house warm in winter.

(5) to heat each square meter of floor area for 24hrs we used one kWh of heat per day.

Posted Friday 20 Apr 2012 @ 3:14:51 am from IP #
Russell Moore
Member

Getting unbiased information from an installer is a bit like going to a Holden dealer and asking if a Toyota would be a better deal than a Holden. After all their reason for existence is to sell their product.

If you have a lot of roof space (even facing W/E) you can still install your panels facing north, you just have to fin mount them on racks. It will cost more to install, and take up more roof space though, but may be better in the long run.

If you go with a 'standard' install on a east or west facing roof, east may be better as you are producing most of your power in the cooler part of the day. Then again if you get cloudy mornings and clear afternoons west could be best.

My installer suggested I would get 22kWh a day on average (I have a 5kW system) but over the last 2 years I am averaging 18.2kWh a day. My panels are at 5º azimuth, 16º tilt.

Posted Friday 20 Apr 2012 @ 3:17:42 am from IP #
ghostgum
Member

I'm in Melbourne, and getting close to the figures estimated by PVWatts v1.
A 4.67kW system at 7º tilt to the North (roof pitch) is averaging 15.3kWh per day (6kWh/day mid Winter, 23kWh per day mid Summer).
See what PVWatts gives for East and West facing. I think the preference is for west facing in Melbourne due to morning cloud. This depends on the height of your neighbours, both now and in the future. We are single storey, and have just had a three storey house built to our west, reducing our output by about 5%.

It may be cheaper to work out how to reduce your usage. We originally used 14kWh per day. Making the computer go to sleep, and replacing the aging side by side fridge and freezer with a single efficient unit cut our power usage to 9kWh per day. Payback time for the new fridge (in saved energy costs) is quicker than for our PV system. But then our freezer was sick and running almost continually.

Have a look at PVoutput.org for systems near you with the west orientation.

Posted Friday 20 Apr 2012 @ 5:34:52 am from IP #
TonyT
Member

Measured Performance of a PV system.

From a 4.56kW PV system with our tilt angle of 12deg and our azimuth angle of 27deg West of North (i.e. minus 27deg) the PvWatts website
http://rredc.nrel.gov/solar/calculators/PVWATTS/version1/International/inputv1_intl.cgi

gives the target for PV electricity collection in an "average" year as
6,354kWh per year.

For its first 12 months of operation, April 2011 to April 2012, with a daily average ranging from a low of 10kWh/day in June up to 27kWh/day in January, our 4.56kW system collected
6,086kWh per year.

This is 96% of the "target".

If installed at the optimum tilt angle of 33 degrees and at the optimum azimuth angle of 10 degrees West of North the pvWatts calculator indicates that a 4.56kW PV system should deliver
6,623kWh per year.

From memory, the system cost was $14,500 after rebates of $6,000.

Posted Friday 20 Apr 2012 @ 6:18:24 am from IP #
Goldie
Member

Hi Josh
There are some good posts here for your consideration. I have all ways suggested getting solar hot water first then see how your electricity usage is. In any case, yours would not be a standard install because the roof faces E - W, so ensure your quotes cover this point. If they have not seen your roof, if weary of the quote, though it can be done using Google maps. Energy Matters installed my 1st PV in July 2009 and I thought them were great. You will get more grief from your energy retailer. Not sure of your area, but give TRU and Origin a miss no matter what. AGL and RED (my retailer) are currently giving 33 cents for the net export. Good luck.

Posted Tuesday 1 May 2012 @ 2:06:03 pm from IP #
muttiah
Member

Thanks everyone for your input. After concluding my research, we decided to go with:
Energy Matters 3.185KW system (13 * REC245PE-BLK panels, and PVI-3.6-OUTD Aurora 3600w Inverter).

It's getting installed on Monday (weather permitting).

Thanks!
Josh.

Posted Tuesday 1 May 2012 @ 11:21:26 pm from IP #
Russell Moore
Member

What direction will they be installed?

Posted Wednesday 2 May 2012 @ 12:14:13 am from IP #
muttiah
Member

They will be in the Western side of my roof - because it also angles towards north. Whereas the Eastern side angles towards south.
Also, due to surrounding trees, there wasn't enough space to custom mount them north.
I'll just have to live with the ~20% loss due to facing west.

Posted Wednesday 2 May 2012 @ 12:17:52 am from IP #
hamish05
Member

Muttiah, 20% loss maybe on the hi-end.

My array faces 10 deg North of West and for last year looks to be closer to 9% down on my area “System Data Summary” prediction. I don't have any shading problems.

I think in Melb we do experience a lot of PV gain in the pm, which can be advantageous for a Westerly facing array, therefore reducing some of the predicted lost production

Posted Wednesday 2 May 2012 @ 5:02:00 am from IP #
muttiah
Member

Hi Hamish, I am definitely hoping that 20% loss would be the absolute maximum lost.

By looking at Google Maps, I think that my roof also faces about 10 deg North of West.

Posted Wednesday 2 May 2012 @ 6:38:54 am from IP #
philbytee
Member

Josh

Might be too late for you to make changes, I expect you probably have now found your best outcome. For anyone pondering over positioning of panels, take a look at my blog post that discusses the difficult situation of an east-west pitched roof:
http://ausdiysolar.blogspot.com.au/2012/03/more-on-location.html
This goes into more detail where the CEC guide doesn't.

If you have a twin track inverter (such as the one Josh will have, PVI-3.6-OUTD) then a configuation such as in this illustration: http://1.bp.blogspot.com/-fkcvj1ur0CE/T1Nwk6cvteI/AAAAAAAAACI/5YtoB0huLpI/s1600/house+e_w+pitch.jpg
using an elevating kit is useful.

Phil

Posted Thursday 3 May 2012 @ 12:47:46 pm from IP #

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