1, 1.5, 2, 3KW Solar Panel Systems

Hi All

Considering having solar panels installed on our roof to, as is the purpose, cut back the electricity bills, especially looking ahead into the future and the sharp increase in price of electricity every year.

Does anyone have a 2 or 3kw or larger system? They are quite expensive but I would think the long term payoff would only take 5 years or so, even less if the electricity keeps increasing in price. We use approx 1800kw per quarter.

Any experiences or recommendations? Im on the Gold Coast. Does your system work as well as expected?


I would first of all seriously recommend looking at your power consumption habits BEFORE going down the path of a grid-tie solar system. You need to know how much power you are typically using, and during what time of the day.
To do this, I would recommend installing one of these - http://www.jaycar.com.au/productView.asp?ID=MS6155
... it's a household Power Monitor, which also stores all the power useage data so that you can plug it into your computer and see WHEN you are using your electricity throughout the day/week/month/year.

If you have a pool, then your typical pool pump ALONE will chew through the power that a 1.5kW solar system will produce each day.

To work out how much electricity a solar system produces on average each day, you need to multiply the power of the system by the number of "peak sun hours" you get in your location - which in the gold coast is 4.5 hours on average (less in winter, more in summer).

So - a 1.5kW system will produce around about 6.75kWh per day.

A typical home, without a pool, and only occasionally using aircon, will use about 20kWh per day on average.

In queensland, you dont yet have "GROSS METERING".... which is where every single watt your solar system produces is fed back into the grid, and you get a credit for all of it. You then buy all your electricity as per normal

Queensland currently only has "NET METERING".... which is where the power produced by the solar system powers your house first, and then anything left over is fed back into the grid, and you only get a credit for what is left over. You only buy electricity when your solar system is unable to meet the power needs of the home.

With GROSS metering, you would get credited for the full 6.75kWh per day, and still buy the typical 20kWh per day.

With NET metering, you would only get credited for around 3kWh per day (depending on how much power your home is using during sunlight hours, i've assumed the house uses around 3.5kWh during the daytime), and would buy only 16-17kWh per day (the missing 3-4kWh has been supplied by the solar system).

.... so from this you can start to work out the savings.
To do this you need to know the rate at which your electricity provider gives you credits for feeding power back into the grid.
Currently, the highest credit provided in QLD is $0.52/kWh from AGL.

So... with a NET metered, 1.5kW grid tied solar system, on a typical household which uses around 20kWh per day.... your power bill would be reduced by:
- 3.5kWh credited at $0.52/kWh = $1.82
- 3.5kwh in reduced normal power usage at $0.19/kWh = $0.62

=== total saving approximately $2.43 per day, or $220/quarter.
.. based on QLD, net metered 1.5kw system, $0.52/kwh credits from AGL.

... in NSW, because we have gross metering and $0.60/kWh credit from our providers... that saving would be ~$370/qtr for a 1.5kW grid tied solar system.

Yeah all of that is pretty confusing, i know.... but at least it can help you work out the savings you might get based on each sized solar system.

... i just noticed you've given your quarterly power useage of 1800kWh. This is around 19kWh/day, so you are a pretty average power user, and my calculations above will work relatively well for you.

I would still recommend installing the household power monitor first, so that you can work out how much power your house is using each week during the daylight hours when a solar system would be producing power... you can then use these figures to work out how much credit a solar system would provide you with.

However - my rough estimate is that you would reduce your power bill by around $800per year.

BUT - the big thing to remember is that these savings all assume that you dont change your power useage habits after installing the solar system. The problem MANY users have is that after installing a grid-tied solar system, they think they have free power - and so they start leaving things turned on all the time and wasting electricity, thus reducing the savings they wouldve otherwise had.
Hi Witzl

Thanks for that, a great read and gives me a little more understanding. Well written as I followed it quite easily. Shame that QLD dont work on Gross isnt it.

Also shame that once you get 2 or more kw systems the price increases dramatically. Any idea if QLD will ever be gross metering?

You were also correct, we do have a pool, so based on a 1.5kw system the pool will gobble it all up.

I will definitely look into the household power monitor before making any final decisions. If the government would have put more incentive into solar, rather than insulation, I think everyone would have been a lot better off.

I would also think that as more companies enter the solar market, and a lot more people go solar, the prices should decrease with the competition.
Hi Brett
I have the state manager from Solarhart(solahart?) coming out tomorrow to do some quotes/measuring on my place so I'll update with my findings what he says to do.
My parents have had a big system for aaaaaaages. They haven't had power bills for ages ... until now. They were very early adopters and have had no end of trouble over the years trying to get credit for what they produce. They had to dispute every bill for years. At one point they started applying GST to the pre-credit bill so they were getting bills consisting ENTIRELY of GST and nothing else and they had to argue with that too. This was back in the days before every man and his dog wanted a solar system.

Their system is currently broken and because it is such an old system, noone knows how to fix it (several have come out), so they aren't getting any credit for power they make at the moment. Not sure if their meter or one of the inverters is broken or even who is responsible.

These systems do have a lifespan, apparently.
thank god what i wrote makes sense!! I was worried i was going to confuse the hell out of everyone!

No idea if/when QLD will adopt gross metering, but i think they will adopt it eventually - to fall in line with the other major states which have either already taken up gross metering, or are in the process of doing so.

Yeah the pool pump is a ******* of a thing! Always have to keep that one in mind :)

Rumpledelf - it might be worth getting a BCSE accredited installer to come out and have a look at your parent's system. It is likely that their inverter has died, especially if it is one of the very early models from many years ago - the technology was quite new back then and not as versatile and rebust as it is now.

They should be able to replace/upgrade the inverter without a drama.
I believe that a Solar HWS gives you a better bang for your buck. Followed by changing electricity usage patterns.

But I am following this keenly as I am planning to install something myself.

Talking hot water, is Gas hot water worth it or does it not save that much considering you need to keep refilling the gas bottles?
Talking hot water, is Gas hot water worth it or does it not save that much considering you need to keep refilling the gas bottles?
Gas hot water is only worth it if you have mains gas, not bottled gas. Otherwise you go through it too fast. We are building in an area without mains gas and are going electric boosted solar, gas cooktop, probably solar heating (budget permitting), but not solar panels.

Our current house has a solar HWS facing south under a tree (when we bought the house the HWS plumbing was also installed OVER THE GROUND to a GARDEN TAP :eek:) and it has to be a freezing, cloudy day for us to need the boost on. They are very efficient little buggers, those solar HWSs :)
great thread guys; I'm following this one closely .... got similar plans for near future.

Witzl, how do I find out more on the metering in Melbourne/Victoria? is it NET or GROSS?

Spectre, looking forward to your update as well. Solar State Services has been advertising 1.5kw system for $2999 in the local papers. It would be good to compare.

Going through my own due diligence, my current thinking is for Solar panel elec, gas instantaneous/continuous flow water heater (the idea being gas is used only when needed ... and not like storage systems), and if $$$ can be stretched then a Sun Lizard climate control system (http://www.sunlizard.com.au/content/solarclimatecontroloverview.html)

Trying to balance between env benefits + my affordibality (inc. ongoing savings from these initiatives)

A quick search around on the internet says that VIC is still using NET metering, but does have the generous $0.60/kWh feed-in tarrifs.
See here - http://new.dpi.vic.gov.au/energy/en...d-in-tariffs/premium-feed-in-tariff-for-solar

Some providers in VIC are even offering $0.68/kWh, such as AGL.

I would also do some of your own due dilligence on system pricing.... all those ads you see for "complete system for $2999" etc, they have you sign over your RECs to them to be able to give you the system for that price.

Note - RECs are "renewable energy certificates", these are the things which give you the "rebate" for your solar power system.
See here for information - http://www.greenenergytrading.com.au/rec-faqs.html

To give you some idea of what the RECs are worth to you... each REC is worth around $42.
Go here to work out how many RECs you can create for a system in your location: http://www.greenenergytrading.com.au/solar-pv-systems-2.html

For me in sydney, i can create 155 RECs for a 1.5kW system.
That is worth ~$6510
So for a "$2999" system, that is really ~$9509 installed.

Shop around and see what people are charging for a fully installed system, and what parts they are using, and what sort of lead time they have.

A LOT of installers cant install systems at the moment because they are waiting on the SunnyBoy inverters, which are not due to arrive in the country until Aug/Sept.

Anyway - just some food for thought.

Oh... and mains gas hot water (continuous flow) is awesome, and dirt cheap to run.
We have gas hot water... and im in the process of investigating the installation of a 2.1kW grid-tie solar system on the roof.
Unfortunately i cant install a GROSS metered system, since its a townhouse and running an extra cable all the way back to the communal meter box would be horrifically expensive, or near impossible - but i've been using the household power monitor i linked to above to measure my daytime power usage to calculate how much credit i would get with a NET metered system. So far it's stacking up pretty good :)
I've recently ordered a 1.5kw system from Beyond Building. They had a special on and I only paid $2k for the system, which means it will pay for itself in around 18 months.
Loads of information about solar panel deals here

I am currently in the process of getting one, preferably from Eco Kinetics - Sopray panel with Aurora inverter.

Good luck for those looking.
Personally - i would be careful of a "high frequency" style grid tie inverter.
These use switchmode technology, which is extremely sensitive and prone to failure if conditions exceed limitations even marginally.

I will be getting a Rich Electric "Solarworx" grid-tie inverter with my system, since they are a low frequency inverter, and made in Taiwan, not mainland China.
Low frequency inverters use a torroidal transformer, and are faaaar more robust and capable of taking a beating - much more likely to last several years versus a made in china high frequency unit.

yes i realise i just went over the top of many people's heads there.... :p
I've recently ordered a 1.5kw system from Beyond Building. They had a special on and I only paid $2k for the system, which means it will pay for itself in around 18 months.

Careful with Beyond Building - i've heard a lot of bad things about them, including shady business practices, dodging up certification of their products, and taking months on end to do installations.

Also, you should read the fine print on their deal! They will probably require you to arrange and pay for the upgrade to your power meter (usually around $500), as well as some other hidden costs on top of your special price of "$2000".

Just be weary!
I have had a thin film system installed since November. I am happy with it and recieve a small credit on my account. I am considering upgrading my panels so I would have a 2KW system.

Unfortunatley with teenagers who leave every dam electricial appliance and light on, we are high power users, so my current system, and if I did upgrade more panels still only supplements my electricity usage. I have saved a lot of money all ready with my system, I have seen a big drop in what I have to pay for electricity.

If I were you, I would install the largest system you can afford. Prices have come down significantly since I signed up for my system which I waited many many months to be installed before the 8 grand rebate finished. Don't just look at price, there are many cowboys out there and many variants on quality of panels, also make sure you install a good inverter.