Turnstyle is on Solar!

As of late August 2012, Turnstyle has a 3 kilowatt solar photovoltaic (PV) power station on our roof. In 2015 we upgraded the system to 5 kilowatt.

Sample daily solar output graph Sample weekly solar output graph

Turnstyle is at a rented premises. The PV system has been organised and funded by Turnstyle but it is owned by our landlord. We negotiated and signed a written agreement with our landlord that will allow us to continue to rent the property for the estimated five-year payback period until we break even on the cost of the system (when we expect that the income we get from the electricity generation will roughly add up to the initial system cost). If we are asked to leave before the five years is up then the landlord will refund us the portion of the system cost that we haven’t recovered by that time. If we leave at any time then we will leave the system for the landlord.

It’s a great deal for the landlord as he gets something for free that adds value to his property.

It’s a great deal for Turnstyle as we get to generate and use renewable energy for no extra cost and not support the burning of fossil fuel or any upgrades to large-scale remote grid infrastructure. If we are careful with our electricity use, we might reach the payback period before five years and then we will get the benefit of the extra income as well.

And it’s a great deal for everyone else connected to the power system because we won’t be causing the need for any new electricity grid infrastructure and because our system will mostly provide electricity to the grid at times of high demand. This reduces the need for grid upgrades to meet increasing peak demand and it also reduces the average price of power. So everyone’s power bills will be lower because of us (and because of all the other houses and businesses with PV). This has been demonstrated in areas where there is already a large amount of PV installed, including Germany and South Australia.

You can compare Turnstyle’s output to that of the University of Queensland 1220 kW system at UQ Solar Monitoring. The UQ system is currently the largest rooftop PV installation in Australia.


Performance (as at 26 Mar 2017)

Turnstyle solar generation graph

For the 3 kW system (Aug 2012 – Oct 2015):

Worst solar day: 20 Feb 2015: 1.0 kWh (heavy cloud and rainy all day).
Best solar day: 12 Oct 2012: 20.6 kWh (cool, windy and sunny).
Average solar day: The average daily solar generation was 13.7 kWh/day.
Total production: 15.6 MWh
Average capacity factor: 19.0%

For the 5 kW system (from Oct 2015):

Worst solar day: 16 Jul 2016: 2.3 kWh (cloudy all day).
Best solar day: 21 Dec 2015: 42.0 kWh (sunny all day).
Average solar day: The average daily solar generation to date is 27.5 kWh/day.
Total production: 14.2 MWh to date.
Average capacity factor: 22.9% to date.

Gaps in data:
Jan 2013: Brisbane floods, electricity network down for 3 days.
Jun 2015: Inverter switched off accidentally by Turnstyle users, unnoticed for 2 days.
Aug 2015: Turnstyle roof replacement, panels removed for 11 days.
Oct 2015: Added panels to upgraded to a 5kW system – system switched off for 2 days.
5 Feb 2015: Dangerous oven failure, power switched off for a few hours.
27 Jan 2017: Replacement of power poles in street, power off most of the day.
13-16 Feb 2017: AC circuit breaker tripped, unnoticed for 4 days.

The data in the above graph is taken from our inverter. This is not an off-grid system so our PV system switches off if the grid is down.

For the nerds amongst us, we correlated the first year of Turnstyle’s daily output against the Bureau of Meteorology measurements of sun hours per day. The graph below shows that the output of our solar panels seems to be pretty well correlated with the sun hours measured by the BoM in Brisbane.

Correlation graph



The performance of the panels will slowly reduce over time – they have an output warranty of 95% of nominal power after 5 years and 80% after 25 years. When we were planning the system the Turnstyle household and space (10 Laura St) was using 13 kWh of electricity per day. Since the solar installation we have used an average of 12 kWh/day and our solar panels have produced 14.5% more electricity than we use. Thanks to everyone who’s been turning things off when they’re not in use! The excess will be helping to power our neighbour’s houses.

From August 2012 to September 2014:
* 10,513 kWh of electricity was produced by our PV system (average of 13.7 kWh/day).
* 9,180 kWh of electricity was used at Turnstyle (average of 12.0 kWh/day).



Special thanks to all who have helped to fund the Turnstyle PV installation, including:

* A large donation from the (retired) UQ EcoBug Food Coop;
* Your donations to Turnstyle;
* Loans from members of the Turnstyle Bulk Buyers Cooperative and the Turnstyle residents.


Installation Process

For anyone who’s wondering what the installation process is like, here is a summary of what happened for us:

April 2012
Turnstyle residents start discussing solar.

22 June 2012
Contract signed with an installer and deposit paid on a 3kW solar PV system. Installation is expected by end of July.
This was possible after the following steps:
* Discussions and presentations about home solar by a couple of suppliers.
* Various quotes obtained from different suppliers.
* Much discussion in the house about which system to go for and how to pay for it.
* The drafting and agreement of a contract with our landlord to let us install the system.
* Discussion with a couple of groups about helping us to fund the system.

5 July 2012
Network connection agreement received in the mail from Energex (a Network Connection Agreement for an Inverter Energy System). We signed it and sent them back a copy.

9 July 2012
The installer’s electrical contractor came around to look at the meter box, roof, etc. As expected, we are likely to need a $150 backing board upgrade in the meter box, but otherwise all good. He reckons installation will be in 1-2 weeks.

10 July 2012
Agreed to the backing board upgrade for the meter box. Installation scheduled for 17 July.

17 July 2012
12 panels (3 kW) installed and generating. Discovered after a few hours of it running that our meter is counting UP instead of down so we are paying our retailer for the power that we are producing for them. Switched off the solar until Energex comes to change the meter (they say this may take up to 10 business days).

1 August 2012
Energex had advised us that the meter would be changed today. They didn’t show up. We called them the next day and were told that we just had to wait and they would come soon.

17 August 2012
Lodged a complaint online with Energex that a month had passed since they advised us that they had all the required paperwork to schedule a meter change yet we’ve not been given any idea when they will change the meter (other than their website information which states that it should have happened within 10 business days). Our panels are still sitting idle on the roof.

20 August 2012
Our meter was finally changed and our system is up and running. Woohoo!

4 September 2012
Sorted out a few installation issues (some panels had been installed facing the wrong direction. Hmmm). Production is now full speed ahead!