Tuesday, October 21, 2014

New PV system

We first got PV (photo voltaics or solar power) 6 years ago and the 1.1kW system has done us well. We recently had a new roof put on so we had to remove the solar panels and I thought it might be a good idea to upgrade our PV system at the same time. This is how the old system looked.

The 1.1kW system cost us $6,500 and in 2010 we qualified for the new WA Feed in Tariff (FIT). This pays us about 48 cents a kWh that we feed to the grid. The FIT runs for 10 years to 2020. A while ago our energy provider (Synergy) decided to reduce the amount they paid people who don't get the FIT for power fed to the grid from parity to what they charge their customers (28 cents) to about a third of parity (8 cents). That got me thinking, when the FIT ends what will our power bills cost us? The amount shocked me, about $600 a year for us measerly 5kWh a day users. I thought well I'll just upgrade my system in 6 years time and we'll be right. Then I thought wait a minute, why don't we upgrade now and the new, bigger system will pay itself off much more quickly with the FIT. I checked the rules which state that you can keep the FIT if you keep your original inverter. Luckily we got a larger inverter than our system required, a SBA 1700 which allowed for a bigger system.

So, now to choose new panels and sell the old. I thought it would be hard to sell the old Kaneka thin film panels considering new panels sell for under $1 a watt these days. However I was pleasantly surprised when an ad in Gumtree got many people interested. The first offer was $900 for the 1.1kW Kanekas, an offer I couldn't refuse. It turns out that the buyer wanted to upgrade his own system and needed that vintage Kanekas to be compatible with his other panels.

 We were told that we could overload the inverter by placing some panels facing west and some north, so we decided on around a 3kW system. The choice of panels was between Yingli, Daqo and REC. The first two are good quality chinese panels, the third very good quality European. We decided on the RECs which should give better performance over a longer period of time and have a world leading energy payback time of one year. The REC 260PE polycrystalline panels are now installed in two strings of 6 panels, giving us 3.12kW. This is the west facing, tilted array on the garage roof.

And here's the North facing array with the solar hot water system alongside.

This upgrade cost us around $4,600 including removal of the old panels. Subtract the $900 we got for the old panels and the total cost was $3,700. It should pay itself off in about three and half years and then we'll have another two and a half years of FIT before we go back to the stingy rate. Our power bills will be in the negative (ie a credit) for the foreseeable future so the money is a great investment as well as good for the environment. Despite being bigger in kW, this system is much smaller in physical footprint and this allowed us to move the solar hot water system further up the roof into a less shady spot.

Now, let the sun shine all day and the rain come at night...


  1. Hi,
    I'd be very interested to know and compare your e-daily kWh outputs now that it is getting warmer here in Perth.
    Considering 1560W face north and the other 1560W face west, what sort of outputs do you get @ 12pm, 4pm, 6pm ? (Oct2014) What time in the arvo does that garage roof get shaded ?

  2. Hi

    These are the readings for Friday and Saturday (31st Oct and 1st Nov 2014):

    Friday: 10am: 2.84, 12pm: 6.07, 2pm: 9.64, 4.20pm: 12.65, 6pm: 13.18

    Saturday: 10am: 2.87, 12pm: 6.03, 2pm: 9.51, 4pm: 12.53

    The garage roof gets shaded at around 4pm these days.

    How does this compare to you?

    Cheers, Adam

  3. Hi Adam,
    Whom did you buy your solar system from?
    We had someone around from Ysolar (used to be Diamond cell solar) which seem to offer a very interesting system of ET panels with separate inverters. We need a 1.5kW system but it seems to be very expensive but they give a huge 3000 dollar bonus if you sign up on the day, and that is where we don't go in, as it's too pushy.
    You seem to be happy with your REC system so I wouldn't mind look into that one a bit deeper.
    We always had too much shadow on our roof, but now with the seperate inverters it seems to be possible.

  4. Hi Wilma

    We just got an electrician to do the install, but I would recommend getting a few quotes and going with someone you trust. Have you tried Energy Matters?

    I've heard that micro inverters are very good these days so that will be the way to go if you have got shading issues.

    I hope you get a good system sorted out.

    Cheers, Adam

  5. Thanks Adam, we are dealing with a ceiling insurance problem at the moment so all solar is on hold for a bit, but need to dig in again. Just found out we need council approval as we have local heritage on our house...
    Will check out Energy Matters, as we definitely need to get some more quotes.
    YSolar came with a new offer, the total is half the price now as it was quoted before the rebates were taken off... that all sounds a bit fishy to me and they are desperate to sell... definitely makes us aware to check out far more about solar before we spend on it.
    Thanks for the reply!