NB: Some of the information about Solar Feed-in Tariffs and return on investment in this article may be out of date. See our Solar Feed-in Tariffs page for up-to-date information on state-by-state programs. A good way to maximise the output of your solar PV system is to have it mounted on a solar tracker. Solar trackers can boost the electrical output of your PV system significantly, allowing you to earn more income from the feed-in tariff. However, as discussed in this article, the economics of solar trackers are more suited to large installations, and are actually more dependant on the level of feed-in tariff assistance offered then geographical location. 

What is a solar tracker?

A solar tracker is a device that tracks the sun as it moves on its path through the sky during the day, exposing your PV cells to an increased amount of sunlight and hence producing more electricity. This is because PV cells work best when they are directly facing the sun. The angle of the sun in the sky changes throughout the year as the tilt of the earth relative to the sun alters. In summer the sun is high in the sky and is also in the sky for longer as it travels through a longer arc length. In winter the sun is lower in the sky and is around for a shorter time as it travels through a shorter arc.

Variation in the sun's path during the day and the seasons - www.rpc.com.auVariation of the sun’s path during the day and the seasons

This effect is accentuated the further you are away from the equator. In Tasmania the days are very long in summer, and very short in winter. In Darwin there is much less variation.

How does a solar tracker work?

A solar tracker is a mechanical device that works by following the sun on its path during the day. There are two different types of mechanisms that are most commonly used “ active trackers and passive trackers. Active trackers are directed toward the sun by electrical circuitry in the form of light-sensing photosensors. Motors and gear trains are then employed to direct the tracker as commanded by the photosensors to the sun’s direction. Active trackers contain electrical components and hence use a small amount of power. Passive trackersuse a hydraulic mechanism that responds to the heat of the sun. A low boiling point compressed gas fluid is driven to one side or the other by the sun’s heat, creating gas pressure and thereby moving the mechanism along. Passive trackers generally do not consume any power. Typically, active trackers are more accurate then passive trackers, and hence favoured for uses where a pinpoint degree of accuracy is required, for instance where concentrating solar collectors are used. For solar PV applications the accuracy of passive trackers is more than sufficient.

What happens when the sun is obscured by cloud?

On cloudy days your solar cells still produce energy as there is still light, although their performance is obviously reduced. In such situations the solar tracker will, by acting on the same principles, orient itself optimally to pick up the most reflected ambient light. Once the sun starts shining again, it will re-orient itself to face it.

What types of solar trackers are there?

There are two main types of solar trackers, single-axis and two-axis.

Single-axis

Single-axis solar trackers follow the sun from sunrise to sunset as it moves in the sky through the day from east to west. They are called a single-axis trackers as the mechanism only rotates in one plane around a single axis. The axis can be oriented so that the cells stand up at a tilt (called a polar axis) or lie flat (called a horizontal axis). Horizontal axis’ are more suitable for small latitudes (locations in the tropics and closer to the equator “ i.e. northern Australia), whilst polar axis are more suitable for larger latitudes (locations far from the equator “ i.e. southern Australia).

Polar type single-axis tracker - solar-tracking.comPolar type single-axis tracker

The advantages of single-axis trackers are that they are less complicated, and thus less expensive. As can be seen in the figures below, single axis trackers capture much of the benefit of solar tracking. In locations closer to the equator where the sun’s arc through the sky is less variable through the day and through the seasons, single-axis trackers are particularly effective.

Horizontal type single-axis trackers - solar-tracking.comHorizontal type single-axis trackers

Single-axis horizontal trackers are also structurally more rigid and stable, and hence less likely to be damaged during storms. In addition to the normal single-axis options, a new solar PV technology has been developed called Tubular solar, where the shape of the cells themselves are cylindrical, allowing the cells to capture the maximum amount of light as the sun goes through it’s daily cycle.

Single-axis tubular solar technology - getenergysmartnow.com

Single-axis tubular solar technology

Dual-axis

Dual-axis, or two-axis, trackers follow the sun completely. The two axes of rotation allow the tracker to position the solar cells directly perpendicular to the sun’s ray all the time. As they are able to adjust for the sun’s height as well east to west rotation dual-axis trackers fully adjust for seasons as well as adjusting to face the sun as it sits low in the horizon at sunrise and sunset, and high in the sky in the middle of the day.

Dual-axis solar tracker - solar-tracking.comDual-axis solar tracker

Dual-axis trackers capture the full extent of the sun, but they are slightly more complex and hence a little more expensive. Dual-axis trackers make more of a difference at greater latitudes (more southerly in Australia) where there is substantial seasonal variation in the sun’s height and arc.

Disadvantages of solar trackers

  • An added upfront cost to your solar installation
  • Generally require some maintenance
  • Moving parts and added complexity come with the usual pitfalls of risk of breakdown
  • Structurally less rigid then permanent mounts and hence can be vulnerable to storm damage

Performance of solar trackers in Australia

A solar tracker increases the performanc of solar PV panels in the shoulder periods of the day, where a static fixed mount panel would only receive obscured exposure. This can be seen in the graph of two side by side solar panels, one mounted on a tracker, the other static, below.

Performance of a solar PV system with and without a solar tracker - www.solartrackers.com.auComparison of solar tracker and static solar panel performance

The modelled performance of solar trackers for various locations around Australia is shown below. The modelling has been undertaken using the PVWatts Performance Calculator for Grid-Connected PV Systems designed by the Renewable Resource Data Center, part of the US National Renewable Energy Laboratory. The figures below take all of the necessary factors into account, including meteorological factors such as average cloud cover and temperature loss factors.

As the table shows below, installing a single-axis solar tracker will boost your energy output in Sydney over the year by 20%, 25% for a dual-axis tracker. Yearly average increase in energy output (kWh) due to single-axis and double-axis solar PV tracking systems

City

Single-axis tracker

Dual-axis tracker

Darwin

20%

25%

Port Hedland

29%

36%

Brisbane

21%

25%

Perth

26%

32%

Sydney

20%

25%

Adelaide

23%

28%

Canberra

25%

32%

Melbourne

19%

23%

Yearly average increase in energy output (kWh/year for a 1kW system) for a fixed mount, single-axis and double-axis solar PV system

City

Fixed mount* (kWh/year for 1kW system)

Single-axis tracker (kWh/year for 1kW system)

Dual-axis tracker (kWh/year for 1kW system)

Darwin

1570

1888

1959

Brisbane

1405

1695

1761

Perth

1354

1704

1785

Sydney

1460

1756

1826

Adelaide

1471

1809

1886

Canberra

1449

1816

1906

Melbourne

1234

1468

1520

*Fixed mount baseline figures from the Clean Energy Council (see article How much energy will my solar cells produce?)

Economics of solar trackers

As the table below shows, a single axis tracker will increase your solar energy income in Sydney by $177 each year per kW of installed capacity, or $220 each year per kW for a dual-axis tracker. It is important to note, however, that the key factor in the economics of solar trackers is the feed-in tariff rate offered. Additional income generated by the use of single-axis and double-axis trackers due to increased energy production (assumes all the extra generation is sold at the corresponding feed-in tariff rate)

City

FIT Tariff

Single-axis tracker ($/year per kW)

Dual-axis tracker ($/year per kW)

Darwin

18.3c

$           58

$            71

Brisbane

44c

$          127

$          157

Perth

16.01c

$           56

$            69

Sydney

60c

$          177

$          220

Adelaide

44c

$          149

$          183

Canberra

50.05c

$          184

$          228

Melbourne

44c

$          103

$          126

Case study 1 “ 10kW dual axis solar tracker installed in Sydney

Upfront cost of a dual axis 10kW tracker – $20,000 Additional yearly income from tracker – $2,200 Payback time “ approx 9 years Profit (16 years @ $2200) – $35,200

Case study 2 “ 1.5kW dual axis solar tracker installed in Sydney

Upfront cost of a single-axis 1.5kW tracker – $4,000 Additional yearly income from tracker – $330 Payback time “ approx 12 years Profit (13 years @ $330) – $4,290

Case study 3 “ 1.6kW single axis solar tracker installed in Sydney

Upfront cost of a single-axis 1.5kW tracker – $3,000 Additional yearly income from tracker – $266 Payback time “ approx 11 years Profit (14 years @ $266) – $3,724 The above examples show that the economics of solar trackers greatly favour large installations, where the cost per kW of installed capacity for the tracker becomes much lower. For large installations (around 10kW), where the purpose of the system is to generate large amounts of power and feed-in tariff revenue, solar trackers are a very attractive option. As 10kW is the feed-in tariff capacity limitin most states, fitting a solar tracker will allow you to maximise your generation income where no other means are available.

For small 1.5kW installations the upfront cost of a tracker is high, and the payback period is long. In reality, investing the same amount on additional solar cells would yield higher generation volumes, more income, as well as greater environmental benefits.

Kobad Bhavnagri Solar Energy Consultant Solar Choice Pty Ltd

© 2010 Solar Choice Pty Ltd

{ 27 comments }

Allan Hambling February 4, 2010 at 8:51 pm

INstalling 2 x 10kw systems in Coffs Harbour – just read your page – can you tell me what type of 10kw tracker you can obtain for $20K and some contact details please and if you compared any types.

I am considering a system from ET Solar and its cost is about $27K which makes it some what prohibitive?

Are there any Recs yet attached to Trackers?

Thanks, Allan Hambling.

NB Any advice gratefully received.

david linaker March 6, 2010 at 11:23 pm

Folks with a rebate Feed in Tarriff in Vic at 60c per kWh then your 44c figure is wrong. Origin Energy is 66c! kWh. A 1.5kWh System with tracking is like a 2kWh system with no tracking. x4 your savings due to Feed in Tariff and you save over $1,000 every year. So how long before the Track Rack pays for itself? Divide your guesswork by x4 !!

a/ Why show the same 1.5 kWh tracker in Case Study 2 at $4,000 & Case Study 3 at a cost of $3,000? Who’s the supplier? Can’t you quote it down? What variation in cost for Dual Axis, Pole mount vs Single Axis, Roof Track Rack / / / / / /. :) :-))

b/ TrackRack suppliers state that output can be boosted up to 50% and indeed that may be true! Nonetheless, your figure for Melbourne suggests only a 23% boost in the output of a 1kWh system. If the system value/cost is $10,000 and you could boost its output 25% for the cost of a Track Rack – you’d do it!

c/ To gain an extra 0.5kWh, i.e; 1.5kWh to 2.kWh you pay an extra $2,500 for panels and inverter (minimum) over and above the cost of the 1.5kWh system.

d/ Mounting racks are needed regardless and with over 100,000 home systems being installed due to the rebate program RECS, Track Racks need to be offered.!!
Do installers really expect consumers to ring LINAK, ECOSTAR, etc one by one!

e/ The savings with Track Rack are up to 50% more output all day at a four (4) times Feed in Tariff being over $1,000 p.a. in Melbourne. Discard the cost upfront of the cheaper bar rack (not used), and save not less than $2,500 extra in panels and inverter needed to match that efficiency by expanding capacity. Let’s do it!!

Dr Wilbur Hughes August 13, 2010 at 6:12 pm

Many thanks for the thorough analysis. Just a point. The length of the 60cents FIT in NSW is only another 6 1/2 years from 1st July 2010, so the payback may be longer than your calculations.

I already have a 1kW PV system facing slightly east from a northern aspect in BOWRAL in the southern highlands in NSW. I am fortunate in that, despite the inclement weather this winter, we are averaging about 4 kWh per day. As you know, in NSW we have a 60c gross feed in tarrif, government guarranteed for the next 6 and a half years, so maximising generation is well worthwhile.

I have had approved and will be installing an additional 9 kW PV.

I currently notice that at this time of year, the power decreases rapidly after 15:00, and obviously this effect will increase in summer when the sun shifts more west in the afternoon.

Would it be worthwhile and practical to install a tilt tracker on some or all of the panels (There will be about 50 of them). Installation costs about $42,000 and expected tariff will be about $10,000 per annum with the current configuration and no tracking. The panels are a roof installation (TILES)

admin August 18, 2010 at 11:31 am

Hi Wilbur – tracking systems aren’t easy to come by in Australia at the moment, but there are a couple installers in our network who have supply agreements in place for this technology. A good tracking system can increase efficiency by up to 30%. Please email your phone number to sales@solarchoice.net.au and we’ll steer you in the right driection.

Richard Webb March 12, 2010 at 9:22 am

Your comments on payback time for trackers does not take into account the opportunity cost of the original capital. i.e $20,000 invested would earn say $1400 at 7% per annum. So Profit is $2200-$1400 = $800. You also need to add in maintenace and depreciation costs to make a realistic comparison.

By the way I do appreciate the information on this website.

admin July 22, 2010 at 11:39 am

Point taken. Of course, the 7% per annum is also an assumption, and that investment potential may also fluctuate. Additionally, the purely economic cost-benefit analysis does not take into account the environmental benefits of renewable energy. Thanks for your comment.

Lisa Rayner April 15, 2010 at 8:47 pm

Hi, i’m doing a project on a greenenergy dependent house and wondering why more money is generated in Camberra, when the feed-in tariff rate is lower than Sydney?
As well why is more enrgy generated in Camberra then Darwin even though Darwin has a higher enrgy output for the fixed mount, single-axis and double-axis. but there is more of a diffrence of energy outout between the single-axis and the double-axis?
Thanks for your time!
Sincerely, Lisa

Lisa Rayner April 15, 2010 at 8:47 pm

AND great info thanks!

Jim Dixon April 20, 2010 at 2:59 am

Very helpful, well and clearly presented, answers a lot of questions. Thanks.
We live in Australind W.A. and have a 1.4 KW system on roof. Unfortunately the roof angle is a bit low and we only get barely 1.2 kw at best time when panels are cool and sun is bright. We are hoping to add two more panels in the future. What would be the optimum angle for here near Bunbury?

We also spend a lot of time in Tasmania and have 2 X BP 80 watt panels on the caravan roof. I’ve rigged up a single axis demountable frame so I can manually track the sun to some degree. Alternatively I can mount the panels on a “T” pole on the jockey wheel mount and again track quite well rotating the pipe manually. I keep dreaming of an auto system. But being a pensioner I guess I have the time to do it manually. However I love making devices and am interested in some smaller light sensitive switches. It may be of interest that it seems as if P.V. panels work extra well in Tasmania due to the lower ambient temperatures which keeps the panels cooler and the High UV factor. My solar controller has indicated that the panels have put out a little over 1o amps on occasions. That’s with low charge in the batteries of course. Hope this is of interest. Thanks again, regards Jim Dixon

john crane May 5, 2010 at 2:24 pm

Panel cooling is something I have interest in as I have now seen my 300 watt Sunpower panels loose a lot of effeciency when hot and as research shows heat is a killer for out put.
I am in discussion with some firms to look into a cheap method to cool panels to see if it worth while.
But on cold days I have had over 100% out put yet hot days 60 to 70% output,
2.5 kw when they should be yielding 3.8 which the sunny boy will handle.
Like every thing it has to be cost effective and simple and reliable, no use spending money and not making money but it is worth looking at.
At present the investment is saving money but My biggest saving was fitting 40 evacuated tubes to my hot water system, next solar airconditioning.

Paul Happ July 31, 2010 at 12:56 pm

G’day Jim
Of some of the research I’ve been doing lately the optimum angle you’re looking for will match the latitude of your location. Australind’s latitude is 33º 16′ 45.13″ S so ideally your solar array should be pitched at an angle around 33º. Hope this helps
Regards,
Paul

Dr Wilbur Hughes August 13, 2010 at 6:18 pm

To your first commenter: You cannot in NSW offset the benefit of the tracker on a 10 kW system by adding more panels as the is the maximum allowed for the FIT at 60 cents per kWh is 10 kW

If seems a brilliant idea to maximise the generation from a 10 kW system but the mathematics are complicated, especially if you take a loan out ( well worthwhile on a fixed north installation say at $50,000 producing $10,000 pa), but I find it difficult to calculate the financial benefits (not taking into consideration the environment). Solar tracking seems fine on the ground but on the roof? Maintenance of a roof system seems a nightmare.

Dave White October 9, 2010 at 3:33 pm

Does anybody know of a tracking system that has been installed on a roof top in suburbia.Iam building my own duel axis tracker to take my 2kw system , but a ground mounted system would be impracticle. This is all providing i can get council approval. Any information would be appreciated.
Dave.

admin April 18, 2011 at 3:32 am

Hi Dave,
Good luck with your tracker. It’s certainly unusual to see solar trackers on roofs in suburbia, but doing so is definitely technically possible, if not legally. Let us know how your local council responds to your idea.

simon January 6, 2011 at 9:37 pm

thanks heaps for the info.
I have started researching trackers as an alternative to roof mount primarily due to distance from my meters.
I believe I have a perfect roof for a PV system. Single face north facing 25 deg pitch heaps of room 20m * 4m zero shade. However my meters are located 200m away on the boundary of the property. At first i was informed i could run 16mm 2C&E (2 core and earth) cables however after paying my deposit was later told a min of 25mm 4C&E. Based near sydney my provider is saying Gross only meters.

Are you aware of any such runs? Will voltage drop be an issue?
Looking at a 7kw system to be installed early feb. Ground based structure closer to meters not ideal, some shade on east side but is looking like the preferred option at the moment.

admin April 18, 2011 at 2:51 am

Hi Simon,
Voltage can be a problem at that kind of distance–200m is quite a way away! That’s probably whey they are now recommending the thicker cables, which ameliorate the effects of voltage drop.

John Davis February 2, 2011 at 3:21 pm

Hi all.
I have a 1.6K/w system installed for 3 bills now and all looking good, (recovered the cost of the bill.)
But how can I get my own power from the panels to supply say my frig when there is a power cut, which shuts down the lot?

MC February 16, 2011 at 5:58 pm

it is possible , but you really need to find an techie that will do it for you without loosing your REC certificates.

you just need to throw in a storage device (such as a battery) before the power goes back to the grid

Solar charges the batteries and overflow goes into the grid when the grid has power loss it falls back to your own backup (or you could just always run from your backup but nite times the main downer it would suck loosing power at night time as you would have no power source.)

Garry Hickson February 18, 2011 at 9:55 pm

Hi. I am about to set a small solar farm on our Qld property west of the Gold Coast and a little South of Brisbane. We intend to set up 60Kw currently about 550 thin film panels and looking at a more efficent panel (early stages). I am interested in the costs and benefits for a set up like this using solar tracking. We are keen to make it as efficient as possible. This will be a ground mount set up as we do not have a roof that could support this. We currently have a roof mounted 1.5kw system and are happy with it.

admin February 24, 2011 at 1:30 pm

Hi Garry,
Thanks for the comment. You might be interested in reading this newer blog entry about solar farming. We can give you specific advice about the costs and benefits and help you to find an installer who meets your criteria, whatever they are.

To answer your question generally, amorphous thin-film panels tend to have lower efficiency than mono- or poly-crystalline panels, and I’m sure you’re already aware that this means you will need more area of panel to achieve the same result (kW capacity-wise) as poly or mono. More panels means that you will need more trackers, which will in turn mean higher costs for you, as well as a greater area of your property given up to solar panels. If you go with the more efficient poly or mono panels, you will not require as many trackers, possibly saving you some money, not to mention space. If you’re looking for efficiency, your best bet is probably poly or mono panels on trackers. Best of luck with your system!

Robert Boz June 10, 2011 at 10:33 pm

Hi Garry,

Just wondering how far you got with this? As an Australian manufacturer, we have been looking at developing our own tracking system. I would be interested to see what you have developed so far.

Regards,

Rob

James December 19, 2012 at 11:31 pm

Hi rob, how did your company go developing a tracker? I have developed a complete microprocessor controlled tracker system, with supporting windows application, dual axis that solves the astronomical constants based on input latitude and longitude, it even monitors wind speed and places the panel on horizontal position in high wind. Given the prototype is now operating successfully I am looking for interested commercial partners

harry March 21, 2011 at 11:08 pm

Hi
I have just installed a 3kw system which points directly north with tilt capability. I just need to find out the optimum angle of tilt though out the year. I live in Pomona Qld 150 km north of Brisbane,
Any help would be appreciated.
Thanks Harry

admin March 23, 2011 at 11:16 am

Hi Harry,

This would depend on how many times a year you want to readjust the tilt angle! Pomona is just south of the Tropic of Capricorn at about 26oS latitude, which means the sun will be almost right above you at around midday on the summer solstice (Dec 21). Therefore the tilt angles for the key times of year are as follows:

Summer Solstice (Dec 21): 6 degrees (almost flat)
Spring and Autumn Equinoxes (June and Sept 21): 27 degrees
Winter Solstice (June 21): 50 degrees

If you want to calculate the in-between dates yourself, there is an excellent tool for doing so available here. Just subtract the Altitude angle (which will never be more than 90 degrees for your location) for the date you have in mind from 90 degrees. For example, the Summer Solstice altitude angle is about 84 degrees, therefore: 90 – 84 = 6.

Good luck!

Michael Spencer smith June 19, 2011 at 10:04 pm

Any body know where I can purchase a DIY kit
or some plans for a single axis tracker
16 x 190 watt panels

Pearl Ondoy November 26, 2011 at 1:36 pm

your page is highly informative!

graham grant June 29, 2015 at 10:34 pm

hello ,i need a brain to work my single axis solar panels
a controller to move the actuators
i have linac actuators
i have a ten kilowatt system which is set up as 2x5kilowatts systems
so i need 2 controllers,can you recommend something for me please
cheers graham

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