Nov. 26, 2010

Solar Success Story - Clovelly townhouse

Installing a solar power system on our townhouse turned out to be easier than expected - here's some handy info on how we did it and what we learnt along the Geoff from Clovelly.


Early attempts at solar electricity

I looked into installing solar panels several years ago and decided no, based on:

  • I estimated a 9 year payback
  • I needed a development application if the panels faced the street as my North roof did
  • Time taken finding a good supplier
  • The technology was still emerging with costs likely to fall as other Chinese firms started imitating Suntech and manufacturing them as well.

The right time

What reignited my interest in 2010 was Randwick council placed an ad in our council rates letter saying they had tendered and determined a preferred supplier. This was Green Solar Group (, which saved me the time researching the best supplier and the directors are the children of Prof. Martin Green whose research was key in making the UNSW Photovoltaic Centre of Excellence world-renowned. Randwick Council also said solar panels would be exempt from DA, as long as you were not a heritage building, had the panels flush with the roof, and no trees needed to be removed. I contacted the helpful 3-Council GO SOLAR officer who had provided her email address to confirm it was exempt.

The quote

I contacted Green Solar Group. They sent a sales consultant around to give me a quote and explain the process. Before the meeting they used Google maps to estimate how many panels would fit on my roof. I was disappointed to find the solar panels would not act as a backup if we had a blackout as we would need an array of batteries and the solar electricity must turn off if the power goes down for the safety of the workers fixing the outage. I showed the sales consultant our last electricity bill and they input the data into their software, which allowed them to graphically and numerically illustrate the carbon saved, power created and payback period for different systems.

Whether to do it

For researching the decision, Choice have written an informative and recent (June 2010) solar electricity buying guide

Given we were forecasting a 3 year payback and significant environmental benefits, the main issues were having the savings available to pay the upfront cost and having unshaded North facing roof real estate. From memory the Green Solar Group consultant said only about 60% of households have a North facing roof that was unshaded. The installers managed the whole process with the energy retailer, equipment purchases and installation, so it sounded like there would not be many time-consuming hassles.

Note – Government financial incentives and consequently, payback periods have changed since the publication of this material. Please refer to for links to the latest information on Government incentives.

How big?

From what is offered on the web I think most people choose a limited size that maximises the government grant and the return per $ invested i.e. stop around 8 panels or 1.5 kw. But I felt the bigger the better because of more environmental and absolute $ financial benefits. We could go up to 14 panels or 2.6kw. I read somewhere the average Australian household consumption is about 18Kwh in a day, so the smaller number of panels (8) would only make 6Kwh of the 18, whereas the 14 panels would make about 11kwh of the 18. We only use about 8Kwh a day, probably because we don’t have a pool, electric hot water, air-conditioning or use a clothes dryer. Shortly afterwards they upgraded the quote as they brought out new panels which upgraded the maximum output per panel from 185kw to 190kw (the benefits of improving technology).

Financial calculations

Choice crunched the numbers here

I used a spreadsheet (email [email protected] to request a copy of the spreadsheet) and got around 3 years payback and A Net Present Value of about $10,000 for our chosen larger 2.6kw system. As NSW use a gross metering system, I realised our consumption is not relevant to the calculations, only the upfront capital cost relative to the yearly payments for our supply back to the grid.

The inverter

I asked for different brand of inverter to the original one offered to us (Chinese made AeroSharp) as my research on showed some issues with a recall and one electrician was claiming how good the PowerOne Aurora and Xantrex inverters were. So Green Solar Group replaced it with a PowerOne Italian inverter, only a little over $100 more, which is transformerless so very efficient. My electrician brother said they rarely breakdown and if they do you can change the individual part readily. The inverter location needs to be out of the direct sun to avoid overheating and preferably near the meter box.

Strata issues

The Green Solar Group consultant made me realise I needed to get permission from my owners corporation, as our townhouse is a strata title. With only three households in our group and having a good relationship with my two neighbours, this at first was not a concern for me. I received a sample by-law from the 3-Council GO SOLAR officer, which I used as the basis for creating our own by-law with very little changes (except from hot water to electricity) and had them passed at a special owners corporation meeting. The by-laws were good at explicitly protecting the rights of the other owners in the owners corporation, which must have given them further reassurance.

The difficulty for me started when I went to lodge the by-laws (lodged on form 15CB at the Land and Property Management Authority (LPMA). It turned out they would not accept the copy of the certificate of title I had found in the owners corporation papers. They wanted the original, and they wanted the certificate that applied for the common property certificate of title, not the certificate of title for my property itself (as the by-laws applied to the roof which is common property). I looked into getting a replacement certificate of title, and the LPMA factsheet on replacement certificate of title said I needed to get statutory declarations from the parties following the chain of custody of the document up until the time it was misplaced, as well as original or certified copies of my council rates notice (which I had recycled and would not get a new one for a year).

In frustration I contacted the 3-Council GO SOLAR Officer. She put me onto Christine who runs the website, who talked to a few strata managers. They said for a “common property” certificate of title, it should not be that hard. The LPMA technical advisers called me back and said I did not need a council rates notice or the stat decs for the chain of custody. I just needed a stat dec from our owners corporation secretary, saying the original was not passed down to us from the earlier strata manager. Yahoo, that I could do with minimal pain.


They had to break two roof tiles to install the panels. Luckily I had some spares in the garage. It took about a day in total, but the electrician had to come back a second time to link the inverter in the meter box. It was a buzz seeing the wheel on our meter going backwards, as we generated more power than we used.

The Efergy wireless consumption monitor helps you track your consumption, but it is a bit of a novelty once you have checked out how much difference your electricity costs when you turn off the oven (67c/hour) or a light (1c/hour) or a computer (5 cents/hour). Green Solar Group were flexible, helpful and professional in every aspect of the process, not just installation.

Post installation

I managed to grab the Inverter software CD from the installers, which has the driver and software to monitor your inverter output. You can also download it from the manufacturer’s website at You also need an A-B USB cord, which is on some printers and scanners.

Using the inverter I can download at any time a full history of the solar output as it is stored in the inverter’s memory. I checked this and realised the projections assumed all days were mostly sunny. However on overcast days the output dropped to around 16% of the fine day output. Luckily Sydney has over 93% sunny days according to the tourism websites.

The energy retailer is soon to install a meter to measure the output for gross metering , when they will also move to time-of-use metering. They explained I would probably save money on this system, by moving my electricity use (like running the dishwasher) to off-peak or shoulder times. Their letter said if I don’t save money I can opt-out of paying by the time-of-use metering and revert to a charge independent of time. That is great as everyone wins, because we use less of the expensive peak-load electricity and we get a benefit for that.


It is a good feeling knowing we are doing our bit towards helping the environment, and getting a 3 to 5 year payback. There are several hours of time required, but this little blog can help you minimise that and feel more confident in your decision.

If you have an everyday sustainable story to tell, email 400 words and a photo to [email protected] - receive a solar battery charger for every story published.


  • We are moving into a townhouse in Dine Street Randwick...our first issue is that the meter box for this 25 townhouse strata estate is a long way from our this a deal breaker for cost effective installation?

    Jeremy Mawer
  • very good article on solar energy. it described about the production of solar energy and its conversion to use it for home based needs. thanks for sharing.
    Commentb By:

    Solar SA
  • Mark W and Fran Mc are wishing to install solar panels on a roof of 4 apartments. We occupy the top floor and have a north facing roof.
    We are new to the unit block and new to strata requirements. Your experience is valuable information for us while we research the possibility of installation.

    Fran McIlroy

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