Going solar: David – one year on

David and Kate, a young professional couple, installed a 1.52 kW solar power system on the roof of their small modern house in the new suburb of Douglas in March 2011, as described here.  Having recently summarised the performance of my own solar power system over its first year, I asked David how their experiences compared. This is what he said:

We’ve had the solar installed for 532 days so far, and generated 3440 kWh in total, so an average of about 6.47 kWh per day.  It’s not quite a fair average since we started counting from a March install [i.e. it includes two winters but only one wet season], but it still gives an idea of the output.

From memory, I believe we’ve sold about 2200 kWh in total, which would make it about 1240 kWh used off the panels in the house, giving us a net benefit of about $1240 for that time – around $2.33 per day.

Those calculations say the panels will have paid for themselves in two more years time – even earlier if (when) the power price goes up again.

David also celebrated the fact that the power supply company has been paying him, instead of vice versa, because the value of his excess power has been greater than the cost of the power he has used from the grid. What next?

Next step is investigating solar hot water to reduce the reliance on gas…

As for the more distant future, he is not impressed with the slashing (and possible abolition) of the feed-in tariff:

It’s pretty disappointing to not even get 1-to-1 for power sold to the grid – and maybe soon to get nothing at all.  So if we were to get solar at a new house, I think we’d just pay the extra and get a battery storage system.

That’s quite a big step to take, and one that probably deserves a post to itself, but the fact that he would even consider it says a fair bit about how positive his solar experience has been.

Good news on renewable energy

There have been several good-news stories on renewable energy in the last couple of weeks. I haven’t had time to follow them up and write about them, but here they are:

Japan to phase out nuclear power by 2040

Japan has announced it will phase out nuclear power over the next three decades, in the wake of mounting resistance to the energy source after last year’s Fukushima disaster.

Tokyo plans to permanently shut down its reactors by 2040, bringing the country in line with Italy, Switzerland and Germany, which has said it will wean itself off nuclear power by 2022 …

The full story is here.

Gales send turbines into overdrive

While gale-force winds kept emergency services busy across South Australia this week, they also fired up turbines on the state’s wind farms. Figures from the Australian Energy Market Operator show while the winds were howling, more than half the state’s power came from wind farms.

Roughly a quarter of South Australia’s power came from wind farms last year. But the Clean Energy Council’s policy director, Russell Marsh, says when winds topped 90 kilometres per hour earlier this week, that figure was much higher.

“What we’ve seen is over the last couple of days the amount of energy generated from wind power in South Australia has gone through between 55 and 85 per cent since Monday as a result of the very strong winds we’re having at the moment,” he said.

And for a few brief moments in the early hours of Wednesday morning, wind was generating so much power some of it was being exported to Victoria …

The full story is here.

Spanish firm to build ACT solar farm

The ACT Government has announced Australia’s largest solar farm supported by a feed-in tariff will be built in the Territory’s south.

Spanish-based company Fotowatio Renewable Ventures (FRV) will build the facility on 50 hectares near Royalla just off the Monaro Highway in Tuggeranong. The 20 megawatt facility will be made up of 83,000 photovoltaic panels and produce enough renewable electricity to power 4,400 Canberra homes.

The project will cost ACT households an extra 25 cents a week or $13 a year. That is expected to decrease to around $9.50 by 2020.

FRV chief executive officer Rafael Benjumea says the company has extensive experience in solar power farms. “We have built more than 350 megawatts all over the world, investing more than 2.5 billion Euros ($AUS 3 billion) in solar panels,” he said.

Construction is due to begin next year and is expected to be finished in 2014 …

The full story is here.

Going Solar: FAQ’s

Created December 2011, updated September 2012: We spent a lot of time tracking down the facts in mid-2011 before we were confident that going solar was a good thing for us to do. I updated the information in December 2012 in preparation for another installation the family was planning and presented it here on Green Path in the hope that it would be useful to others contemplating the same action. I have now (September 2012) updated it again, mostly because of drastic changes to Queensland incentives. Major changes are in bold.

As of August 2019 the whole post is due for an overhaul because so much has changed at the government level. I have removed broken links here but left the text unaltered, for historical interest as much as anything else.


Both national and state governments have incentives to encourage our move to renewable power generation, while the federal incentives also reward any steps we take to reduce power consumption.

Federal Incentive: RECs or STCs

The federal government, through the Small-scale Renewable Energy Scheme (SRES), gives an up-front lump-sum incentive payment calculated on the amount of energy a solar PV system will notionally produce over its lifetime.
The scheme aims to:

  • encourage the additional generation of electricity from renewable sources;
  • reduce emissions of greenhouse gases in the electricity sector; and
  • ensure that renewable energy sources are ecologically sustainable.

This is achieved by:

  • the creation of online certificates by eligible renewable energy sources based on the amount of electricity in megawatt hours (MWh) generated by a renewable energy power station, or small-scale solar panel, wind or hydro system; or displaced by a solar water heater or heat pump; and
  • placing a legal obligation on electricity retailers to purchase and surrender a certain amount of these certificates each year. The trade in these certificates thereby provides financial incentive for investment in renewable energy.

In practice, this up-front incentive usually appears as a discount on the quote from your installer, who takes the certificates and on-sells them.

When we installed our own system, RECs were issued at five times the expected 15-year output in megawatts for installations up to 1.5 kW and one time (same number) for anything over that. They are now called STCs and credited at twice (same number) for installations up to 1.5 kW and one time for anything over that. The discount for a 1.5 KW system has therefore dropped considerably. At the same time, however, component prices have dropped so the net cost increase is not so significant.

For more information on the federal scheme, see The Small-scale Renewable Energy Scheme (SRES) at http://www.cleanenergyregulator.gov.au/RET/About-the-Renewable-Energy-Target/How-the-scheme-works/Small-scale-Renewable-Energy-Scheme

State Incentive: Feed-in Tariff

The other incentive is the feed-in tariff from Qld Gov’t via Ergon, who pay a certain amount per kWh for power fed into their grid. The payment goes through the power bill.

The bad news is that the Newman LNP government slashed the feed-in tariff for new customers as of July 2012, from 44 c/kWh to a mere 8c/kWh, and has said that, “The 8 cent tariff will end on 1 July 2014. However, the Government will also review the 8 cent tariff by 1 July 2013 to ensure the rate remains appropriate for Queensland,” which sounds like code for, “We will abolish it altogether if we can get away with it.”

Fortunately for early adopters like ourselves, existing customers will continue to receive the 44c feed-in tariff until 2028, “providing they maintain their eligibility for the scheme,” which basically means not changing the account name. That is, if the house is sold or rented out, the feed-in tariff lapses.

Our system is producing just over 6 kWh/day. If it all went in to the grid at 44 c/kWh it would earn us $2.60 per day; if we used all of it, it would save us $1.30 per day by replacing Tariff 11 power at 23.7 c/kWh. Our net benefit must therefore be somewhere between those figures, and in fact it has averaged just under $2.00 in its first full year. (Summary figures for the first full year of operation are here and month-by-month figures are here – scroll down to the comments).

Limits of incentives

  • Basically one system per property and a maximum of 5 KW per system.
  • The Federal incentives dropped in the middle of 2012, when the multiplier for small systems dropped from 3 to 2, and will drop again in July 2013 (see “What are Solar Credits” here).
  • The feed-in tariff is guaranteed to stay the same for 20 years for people who signed up before July 2012 but there is no long-term guarantee for new customers. 

Rental properties

The federal subsidy is available to owner-occupiers and landlords alike. So is the state’s feed-in tariff, except that the payment goes to the person whose name the power bill is in – normally the tenant, in which case the landlord would have to negotiate with the tenant to receive any benefit.

Payback time

In December 2011 I said:

These figures make payback time for our 1.5 kW system 4.5 yrs and for a new system like ours about 6.5 years. That’s not bad, but a 5 kW system is mostly a solar farm, since no extra power would be used by the household. On the same domestic consumption, export to grid would be 6000 kWh / yr and pay the owner $2650 p.a. as well as saving $200 p.a. off the normal bill. On the other hand, it will cost more – about $14 000 – $15 000. On these (very rubbery!) figures, payback time is still, surprisingly, in the 5 – 6 year range.

I haven’t done all the calculations again but ‘solar farming’ has obviously become far less attractive since the state feed-in tariff dropped in July 2012, as that $2650 p.a. would become $480. 

Stand-alone capacity

Grid-connected systems don’t usually have any stand-alone capacity. One installer told me the Australian standards for grid-connected inverters mandate automatic shut-down when mains power drops out. The only way to give your system stand-alone capacity is therefore to install a second inverter (a stand-alone model) and a rack of batteries, for a total cost far greater than the cost of a portable generator and a generator input plug on the main switchboard.

Is PV Solar the best thing for me right now?

This question was answered separately on Oct 22, 2011, here; I haven’t updated it since then, mainly because it still all seems to be correct. In fact, the potential benefits of energy savings seem greater now in comparison to the potential benefits of installing solar power, since the incentives for solar have dropped.

Accredited Installers

Try the Clean Energy Council

Coming Technology

The current monocrystalline and polycrystalline cells are both mature technologies and radical improvements seem unlikely. Amorphous and thin film technologies are newer and potentially cheaper per watt but less efficient (i.e. you need a bigger area to make the same amount of electricity) at this stage and are apparently not really worth considering for domestic installations. See http://en.wikipedia.org/wiki/Low-cost_photovoltaic_cell for regularly updated information.

Flexible cells are coming – there has been a demo set-up at Townsville airport for a year now – and may have their uses but don’t seem particularly relevant to fixed installations. For something further out, look at these printable and paint-on solar cells.


The three big sites for authoritative information are the Clean Energy Council (the peak industry body in Australia), the federal government’s Office of the Renewable Energy Regulator (ORER) and (for Queenslanders – I assume other states have similar sites) the Office of Clean Energy which has a more people-friendly page at Do the Bright Thing. The solar PV guide (pdf) from the Clean Energy Council is good introductory material, but there is plenty more on these sites.

The Desert Knowledge Australia Solar Centre (DKASC) is a demonstration facility for commercialised solar technologies operating in the arid conditions of Alice Springs, Central Australia.

Going Solar: Malcolm, one year on

We installed a 1.5kW solar power system on our roof in the middle of last year. As I said at the time, it took a little while to get it all connected and working the way it should. However, we now have a whole year of data on its performance, so we can assess the annual output and see the seasonal effects.

solar power output chart

The blue curve shows how much power the sytem has produced and, as expected, generally follows day length but with bumps created by specific weather conditions. The amount exported tracks it fairly well, but is reduced by air-con use during the hotter part of the year (the gap betweeen the two curves is widest from Dec-Feb). The spike in exports last September-October, incidentally, is explained by the fact that family members were away from home for several weeks: less consumed => more exported.

Annual numbers are:

  • Total produced = 2220 kWh (6.1 kWh/day)
  • Total exported to grid = 960 kWh, for $425 income
  • Total PV power used at home = 1260 kWh, for $270 savings
  • Total benefit = $700

In the coming year/s we can expect a slightly higher net benefit, since the electricity tariff has recently increased from 20.7 to 23.07 c/kWh. On the same output and consumption figures, the panels should save us an extra $20 per year because of that price rise. However, cutting our daytime power consumption would be even better. If we had used half as much power during the day this year, for instance, our net benefit would have been $130 higher. That is something we will now look at more carefully.

I will keep tracking monthly figures but won’t keep posting them to Green Path so my updates will be less frequent.

Going solar: off the grid

We recently visited Hidden Valley Cabins, 25 km inland from Paluma, for a very enjoyable social occasion and I took time out to look at the resort’s solar power installation.

Hidden Valley is isolated enough that the resort was always off the grid, dependent on a diesel generator for all its power. About four years ago, with the help of funding from a programme designed to help isolated users make the change, they installed a custom built 12 kW system comprising ninety 130W panels feeding into an inverter and a roomful of batteries.

Solar panel array at Hidden Valley
The solar panel array at Hidden Valley Cabins

The panels are mounted on frames on concrete pads just up the hill behind the resort and produce 19,500 kWh per year. The resort only use two thirds of that amount but the extra system capacity ensures that the batteries are fully charged for cloudy periods. The old diesel generator is still in its shed nearby and hooked up to the system as a backup, but I got the impression that it is rarely called upon.

The owners are very happy with the system. They have set up the shed housing the batteries and inverter as an interpretive centre, and have various brochures about solar power for visitors who may want to follow their lead.

The batteries
The batteries

One of the advantages they appreciate most is one I hadn’t thought about: it is silent, and gets rid of the generator noise they had to put up with 24/7. But of course, the savings in diesel fuel are enormous (I did see a figure but don’t appear to have jotted it down – sorry) and they don’t have to worry that they will lose power for lack of fuel if the gravel road is washed out in the Wet … which reminds me to mention that the system has survived cyclone Yasi, much more intense where they are than it was in Townsville.

Problems? Battery maintenance was ‘a bit of a learning curve,’ but that is about all.

System schematic
System schematic (click to read!)

Visit the Hidden Valley Cabins site to read more about the resort and its solar power installation.