Western Australia suspended its 20c/kWh solar feed-in tariff (FiT) scheme at 8am 1 August 2011 with no state-sponsored scheme to replace it (although there is still a Solar Buyback scheme in place from WA electricity retailers). Some people who already have a solar power system installed on their property and are receiving the FiT in Australia’s largest state may be asking themselves: If I want to increase the size of my system, will I still be eligible to receive the rate that I am currently receiving?

Can I expand my solar power system and still get the WA Feed-in Tariff?

The answer, according to the WA Office of Energy, is ‘yes’–but with a caveat. Under WA FiT eligibility rules, solar power system size is determined by the nominal capacity of the system’s solar inverter, which cannot be increased. This means that you may increase your system size and still receive the solar feed-in tariff, but this will only be a benefit to those who have an inverter capacity that is larger than their solar panel array–inverter efficiency typically drops off after its nominal input voltage is exceeded.

If you didn’t have plans to increase the size of your system before the FiT scheme was cancelled, it is unlikely that you would opt to do so now. Unless, of course, your energy needs have begun to soar higher than you ever expected them to, in which case upgrading your system might be worth it even if it means losing the tariff.

Written by James Martin

Source:

Western Australia Office of Energy, Residential Solar Feed-in Tariff FAQ

You are thinking about installing a solar power generation system for your home. Initially, you’d like your system to have enough solar photovoltaic panels to partially or totally meet your energy demand requirements, but you’d also like to have the option in the future to add more. You might do this for a number of reasons: either to feed in and sell your electricity to the grid, or because you are considering putting an addition on your home (such as a pool room…), or adding a granny flat or a garage. How should you plan your system and size your inverter for future expansion?

One cost-effective tactic if you want to keep your options open for the future expansion for the production capacity of your photovoltaic (solar panel) array is to oversize your inverter. Previously in the Solar Choice blog, Prateek Chourdia wrote some general guidelines regarding inverter sizing for the optimisation of efficiency of solar photovoltaic systems. One of the points that Prateek made is that the real production capacity of a solar array is limited by inverter size. That is, the output of your system will not (or should not) exceed what your inverter is rated to be able to convert from direct current to alternating current.

Why oversize the inverter for your solar power system?

Your panels will not always be producing the same amount of power consistently at all times, due to fluctuations in sunlight throughout the day and the effects of heating and shading; inverters are designed with this fact in mind. They therefore have what is called an optimal voltage operational window, which specifies the range of input voltages in which an inverter will function optimally. Although the efficiency may still vary slightly within that window, it does not vary radically. (See the graph above). Generally, if the power produced by your solar power array exceeds or does not reach this window, your system will suffer significant efficiency losses, or you may end up burning out your inverter. If you want to oversize the inverter for your system before you expand the number of panels, you’ll want to make sure that the voltage output of your array falls within the window.

When over-sizing your inverter, the efficiency of the system (see graph at top) depends on what your average point of operation across the year is. This in turn will be based on the configuration and operating conditions of your solar array. During the design process, inverter manufacturers predicted that people may want to increase their solar PV array size over time, and designed them with this in mind. This is why modern inverters have a fairly wide operational window to accommodate fluctuations in power generation with minimal efficiency loss–or possible system expansion. In the case of the graph above, for example, efficiency for an inverter operating within its the optimal voltage operational window is between 85-95%.

Some inverters (transformerless and high-frequency transformer inverters) are optimised for efficiency toward the high end of the efficiency window, while other inverters (those that have conventional transformers) reach their peak efficiency toward the low end of the window. Generally, if you are planning to add panels to your system in the future, transformerless or high-frequency transformer inverters are the way to go. It is important to match the output of your solar PV array with the operational window of the inverter, not only for efficiency, but also for the well-being of your system: if your array voltage exceeds the rated voltage of the inverter, you may void your warranty!

So in summary, if you are planning to add more panels to your existing system, make sure that you have a clear idea of the capacity and type of panels that you would like to add on, and the total voltage of the expected system. All of this can be calculated based on your expected future home energy consumption. You will then be in the position to select the appropriate inverter.

Written by James Martin

Solar Choice Analyst

© 2010 Solar Choice Pty Ltd

Sources and Links:

Personal communication with Prateek Choudria–MEngSc “ Photovoltaics and Solar Energy, UNSW

Previous related Solar Choice blog entries: Sunny boy visits Solar Choice : Feed-in tariffs state by state : Can I add a second solar system to another building on my property? : Optimising solar system efficiency through inverter sizing : Troubleshooting your grid-connected solar power system : Home energy consumption vs PV system production : AC vs DC explained : Transformerless vs Conventional Inverters

The Solar Choice blog is full of good advice. We have written about how to orient your solar panels, how to determine what size system you’ll need, how much you might expect to earn or save through government solar power incentives (feed-in tariffs and RECs) with a solar PV system, and how to troubleshoot electricity production issues with your system, plus a number of FAQs about related topics. Recently we came across a satellite photograph demonstrating something you might want to keep in mind when you install an array on your roof: Trees have a tendency to grow over time!

When these panels were originally mounted, the trees now causing problems may have been mere saplings. A clear reminder to keep an eye on your trees so that they don’t sneak up on your solar power array.

Solar photovoltaic arrays don't do much good if the sun never manages to reach them...

Written by James Martin, image stumbled upon by Alex Chiddy

© 2010 Solar Choice Pty Ltd

Determining the orientation and tilt angle of your solar power generation system is one of the most important considerations in designing your solar power system. As we have mentioned before, in the southern hemisphere, due North is the optimum orientation for panels. But not everyone has a perfectly oriented roof. When your two best options are East or West, which should you choose?

During the course of a day, the sun passes through the sky in a particular arc that varies throughout the year due to the earth’s orbit (see top image). The arc is always symmetrical from East to West, measuring out from the centre point, which would be midday. This means that from sunrise to midday (not counting during daylight savings time) and from midday to sunset, there is an equal number of hours of sunlight on one particular location. (You can see how this applies to your particular location using applications like SunCalc, which shows you exactly how the sun moves through the sky at different times of day.)

So, if your home or roof does not have a Northern aspect, but does have two roofs that face due East or due West, you may be asking yourself which side would be a better location for the most power generation. Making the right decision will impact on how much money you can save or possibly even make under the solar power incentive schemes available throughout Australia.

The first thing to consider is shading, of course, which can potentially have a big impact on the productivity of your system. Is either side of the roof shaded by nearby objects? If one side is shaded, choose the other side.

If you’ve determined that the shading effects are either non-existent or basically the same on both sides, then the next thing to consider is the angle of your roof–if possible, you don’t want to have to put in any mounting brackets or solar trackers. The two sides of your roof may be tilted at different angles: you will want to choose the side which is closer to being horizontal, as this will result in the most insolation (incident sunlight) throughout the day.

So, you have determined that shading is not an issue, and that both sides of your roof are symmetrically angled. What do you do now? Although Australia is well-known for its unpredictable climate, you will need to consider when you tend to have cloudy weather more often–in the morning or in the evening. This will depend on your location and climate, but for many locations (including Sydney), mornings have a greater tendency for overcast skies. Shading, even from clouds, can reduce the output of a system by up to 90%: any time it is not sunny, energy production will drop. So, in essence, the answer is that you should try to put your panels on the ‘sunnier’ side of the roof in terms of weather: if you have cloudy mornings more often, the West roof, and if you have cloudy afternoons more often, the East roof.

That being said, if you are thinking strategically about power consumption and pricing, you will want to keep in mind that in most states the price of electricity is higher around 5pm. For example, in NSW the peak electricity price at 5pm is $0.36, which is roughly twice the shoulder rate just prior to that time. If your panels are west-facing, you will be producing optimally right about this peak electricity time, potentially providing you significant savings on your bills.

Written by James Martin

© 2010 Solar Choice Pty Ltd

Sources and Links:

Previous related Solar Choice Blog Entries: Orientation and tilt angle for your solar power system : Solar Power Incentive Schemes in Australia : How to install solar panels on your roof : Solar Trackers

On our blog we often receive comments from people who have installed solar power systems but, for some reason or other, are not seeing the optimal or anticipated performance from their system. Although the best approach in such a case is usually to contact your installer and ask for advice (especially if your system is new!), there is a short-list of likely problem areas that you may be able to investigate and remediate on your own, saving you the bother (and possibly the cost) of having your installer come out and have a look.

Solar power system problem diagnosis starts with your system type

Diagnosing any problem with sub-optimal power production begins of course with the question: What kind of system have you got? Specifically speaking, have you got a grid-connected or off-grid system? The follow-up questions you will need to ask yourself will differ depending on your answer to this question. This entry deals primarily with grid-connected systems, however, as most troubleshooting techniques can be applied to both types of systems. The biggest difference is that off-grid systems have batteries and battery-associated components and therefore tend to have more places where things may go awry. Keep an eye on our blog for an entry dealing with off-grid/battery troubleshooting to be written sometime in the near future.

What’s your problem?

Let’s imagine a few different scenarios:

1. Your system has not been producing at the anticipated Wattage right from the outset. By this, I mean that your system is either consistently putting out less-than-expected power throughout the day, or your system is only producing at capacity at certain times of day and the rest of the time is producing less. A typical complaint would be something along the lines of: “My installer told me I would generate 20kWh a day, but I’m only getting 5kWh per day!” Since your system is new and most likely still under warranty, the solution here is easy: your best bet is to ring up your installer and ask for assistance. They will know best how to handle the situation, and in any in any case are probably obligated to do so under whatever agreement you have with them.

2. Your system was working fine when suddenly and for no apparent reason there was a regular and persistent drop in power production, either throughout the day or for part of the day. You’ve had your system for a while and it may no longer be under warranty, and you want to see what you can take care of on your own. The first thing you should do in this case is dig up and dust off the maintenance manual that you should have been given when you had your system installed. There should be a troubleshooting guide contained within its pages. If you’ve managed to somehow lose your manual, your manual contains no troubleshooting guide, or you never had a manual in the first place, the steps detailed below will provide you a general guide to DIY maintenance.

Solar power system troubleshooting: Appliances, shading from neighboring objects, cables, panels

Appliances: Could the drop in power just be because I’m using more electricity?

The first thing you, as a wise system owner, will do is think hard as to whether you or someone in your home has recently started using any new electronic devices that may be increasing your energy demand. Next you might want to check and see if any of your devices, especially one that is on pretty much all the time such as a refrigerator, hasn’t suddenly malfunctioned and begun sucking up more power than it’s meant to. If you have a good monitoring system for your panels, you should be able to see this clearly, and if it is indeed the case, well, you’ve just saved yourself a lot of time and effort troubleshooting the rest of the system. If you can rule this possibility out, then you might need to consider some of the system components.

Immediate or nearby shading

You’ve been monitoring your system and one day noticed that they’re not producing the amount of power you expect them to. Your ability to monitor your individual panels will depend on your system configuration.

If you have a multiple-inverter setup (not so common in residential systems) you may be able to monitor each individual panel or each ‘string’ of panels. Generally speaking, however, most residential systems are designed with only one inverter, which means that you are only able to monitor all of the panels as a single unit, without the precision that a multiple-inverter set up might allow you. In this situation it’s more difficult to narrow down where the panels could be having problems, so there’s a bit more work involved. Let’s start with the most obvious potential issues: shading (in all but amorphous PV arrays) and heat fade, which is caused by excessive heat.

Shading can occur as a result of something actually on top of your array, such as a leaf, a pesky vine, or a rogue plastic bag, that blocks sunlight. This problem is easy to remedy: remove the offending object and see if your performance goes back to normal! (While you’re at it, you may want to give your panels a good washing”whilst the effect is not as dramatic as more blatant shading, accumulated dirt can affect panel productivity by 5-10%.)

The more insidious and intractable form of shading is that which comes from surrounding objects: trees that have grown tall enough to come between your panels and the sun for part of all of the day, or structures that have recently gone up around your property. If this is the sort of problem that your system is encountering, it should be fairly obvious, because your system may only be affected at certain times of day or certain times of year. It may be impractical to sit on a perch and monitor your panels during all sunlight hours throughout the year to check to see if shading is indeed occurring, but you should be able to pick out any likely shade-casting objects in the vicinity. You also have the option of visiting a site like NearMap.com, which can show you how your address is affected by nearby shading year-round. Although NearMap will not enable you to see shading throughout the day, it will allow you to pick out generally where the shading may be coming from throughout the year. Or you could check the problem yourself by simply waiting for the power to drop off, and then go out and have a look at your panels to see if there is some shading happening.

…or is your problem in the system itself?

A word of warning: Whilst it is true that you can do some of the troubleshooting yourself, a solar power system, no matter how small, is a live electricity production unit. There are certain parts of the system, especially the wiring, that if handled inappropriately or while connected can result in injury or even death. The last thing you want to do is become a casualty of your own ignorance of electronic circuits. So, if you do not know exactly what you are doing, consult a professional electrician or a certified photovoltaic (PV) system installer to do it for you or give you specific advice. Likewise, climbing up onto your roof to inspect your panels carries a similar risk. Use the utmost care or consult a professional. At the end of the day you’re better off with a lighter wallet than in hospital or the morgue.

Well then! If you haven’t been frightened off by the dire warnings, let’s start troubleshooting with the components common to both grid-connected and off-grid systems, then: wiring, panels, and inverters. Then we’ll look at the components specific to off-grid systems: batteries and charges/charge-regulators.

Faulty wiring or panels in a solar power system

Conducting selective shading test

If you suspect that a solar panel itself or its wiring is causing problems for you, there is a simple procedure that works especially well with mono- or poly-crystalline panels (amorphous panels are not as vulnerable to shading effects) that you can perform to test your hypothesis: the selective shading test. If you have a parallel or series-parallel array configuration, this test will help you determine which panel or which series is the culprit. This is because the voltage of your system is relatively constant, regardless of shading, while the current is greatly affected by even partial shading. Voltage increases when you line up panels in series, but current increases when you put panels (or a series of panels) in parallel with one another. If you only have one series of panels in your array, however, the shading test may only tell you whether there is a shading problem, not where it might be. (For an explanation of the difference between current and voltage, read this previous blog article. The rules of current and voltage also apply to batteries. You can read about how battery banks are designed in this previous article.)

So how does one conduct this test? Well, shading even just a few cells in a mono- or poly-crystalline array will result in a significant and sudden decrease in output; shading even just 4 cells should result in a drop of more than half the output of a panel or string. With the array connected and working, monitor the output while you shade the panels. If there is NOT a significant drop in output when you shade the panels in full sunlight, you have found your faulty panel/panel series. The next step is to figure out what part of the system this could be originating from.

The effects of heat fade on your solar system

Another reason you are experiencing a loss in productivity might be that your panels are too hot, resulting in a phenomenon called ‘heat-fade’, where your voltage drops. This is especially likely to happen if you have a weak cell somewhere in your array. Panel performance is usually calibrated at a test condition temperature of 25C (Standard Test Conditions or STC), and operating above this temperature results in generation losses. Your installer should have taken the effects of heat into account when considering the Normal Operating Temperature and Conditions (NOTC), the actual expected temperature range on the ground where you are. The expected reduction of output in volts per degree of temperature above the STC temperature should be provided in the specifications of the brand and make of panel you have installed. (Incidentally, heat actually has an insignificant but positive effect on current; however, this is greatly offset by the voltage and therefore overall associated power losses.)

Some reduction in capacity is to be expected with heat gains, and your installer may have told you how much power production to expect at a certain temperature. You can check if your system is being adversely affected by the heat by cooling your panels with water and observing the system output to see if there is a significant change. When so cooled, does it rise to normal output levels? If so, you need to determine where the weak link is. You can do this by disconnecting the panels in your array and checking their open circuit voltage (Voc), which, in a nominal 12V array, should be about 18V (All depending on the specifications of your panels! This number will increase proportionally with higher-voltage systems; e.g. a nominal 24V system would have a Voc of about 36V). If your Voc is less than you’d expect it to be, then either a portion or the whole of your system has a problem. You can go back and conduct a shading test as described above to try to find the faulty bit.

Checking for faults in the wiring and connections in your solar power system

If neither of the two above tests reveals to you where your problem may lie, your power loss may be occurring somewhere in the balance of system (BOS), however–wires and connections are a prime suspect, and if you have an off-grid system, you’ll need to investigate your batteries.

1. Check your wiring or have it checked by someone who knows your system

Solar panels themselves tend to be fairly dependable: because they have no moving parts there’s little than can go wrong with them mechanically. If you’ve ruled out the potential of panel-related problems, you’d be smart to look at your wiring, as this is often where problems occur in a system.

A. If you find yourself suffering from a total loss of power (in grid-connected systems you won’t actually be subject to a blackout, but you should notice the lack of production by looking at your meter/monitor), the first place you’ll want to go is your circuit board. Have any of the fuses blown? Try switching them back on if they have, and keep an eye on them to make sure that it doesn’t happen again. If it does, there’s something happening in your system that is causing the circuit to blow out. This could be a faulty connection, or a component may have gone haywire. Hopefully your circuit board is labeled clearly so you know which circuit is having the problem, enabling you to narrow down the likely culprits.

B. Loose or totally disconnected cables will result in partial/sporadic or total loss of power, respectively. Check all the connections to see if anything is obviously amiss–a wire is hanging loose or barely connected. Don’t attempt to fix it yourself unless you are certified to do so,  you know exactly how your system functions, and you know for an absolute fact that there is no electricity coursing through the system. Even if you can’t do it yourself, at least you’ll be able to rest at some ease knowing where your problem lies, and call someone to fix it with confidence.

-The problem of corroded connections is especially common with older systems, as oxidisation of exposed metals happens naturally with the passing of time. The easiest solution is to clean any corroded bits first and check that the connections are tight. If this is where your problem is originating, you should be able to see your power come back after you’ve done this. But again: this should only be attempted if you are certified to do so. Playing with wires is risky business.

-If the problem persists but the connections all seem to be corrosion-free and snugly connected and that all the soldering is in properly in place, and you’re certified to do so, you might go through each connection and check with a voltmeter in order to try to find cables that have stopped conducting electricity. This problem is highly unlikely, however, unless you are aware of an incident, such as a cyclone or tornado or car/building accident, that could have compromised the integrity of your cables. In any case, checking some of the connections might be tricky, especially the ones underneath your panels. If all the accessible connections seem to be checking out all right, you can move on to troubleshooting the panels themselves.

How about my inverter?

It’s also possible that your inverter may be oversized or undersized, but if this is the case, you should have been aware of this issue from the outset of having your system installed. You can read more about the importance and effects of inverter sizing in this previous blog entry.

But the best medicine is preventative

Especially in the case of problems with wire connections, the best strategy is to be proactive in looking for potential problems with your system, keeping a regular log of its function and noting if anything seems amiss. This is especially true in an off-grid system, but also important in grid-connected systems. The earlier you notice and deal with a problem, the more likely it is that you’ll be able to take care of it quickly and avoid losses, saving or possibly making you money!

Written by James Martin

Solar Choice Analyst

© 2010 Solar Choice Pty Ltd

Resources and Links:

Previous Solar Choice Blogs: Stand-alone system battery maintenance : Types of photovoltaic panels : AC vs DC electricity : How to size a battery bank : Solar Choice FAQs

You are now mentally and financially prepared and willing to go ahead with a solar panel (photovoltaic) installation on the roof of your home. The only problem is, after having your potential installer come out and have a look at it, you’ve found out that your roof has got asbestos in it and your installer has reluctantly informed you that they will be unable to carry out the install. Where can you turn? Fear not! There are potentially a few other choices available to you.

Asbestos fiber, until a few decades ago a common component in buildings as a fire retardant and noise insulator, can have serious negative health repercussions for those who work with it. It can crumble and decay over time, and can then be inhaled as it floats around invisible in the air. Agitation or removal can induce its disintegration, and a common tactic for dealing with it when it is discovered is to not touch it at all, or to contain it as it is. It’s no surprise, therefore, that an installer might not be particularly keen to start drilling holes into an asbestos-laden roof.

So what are your options?

-If your solar installer agrees to do the install if you get rid of the asbestos, you could look into having it removed professionally, thereby clearing the way for construction. Make sure that the remover is reputable and professional–asbestos removal is not a job to be undertaken lightly.

-More likely, however, it would be wise to find an alternative spot on your roof, or the roof of another building on your property (e.g. a garage) with a north-facing aspect. By doing so you may be able to avoid the asbestos issue entirely and still stand to reap the benefits of solar power, potentially even if the new roof you have selected is in a sub-optimal location. You can contact a Solar Choice broker directly, or ring us on 1300 78 72 73 for detailed regarding your options for placement

-If you own a large property with sufficient space to do so, you could consider a ground-mounted installation near your home.

-It may also be possible to install photovoltaic panel awnings above your windows or doors (such as can be seen here and in the image at top). Depending on the aspect of your building and space available on walls, this would actually enable you to choose an optimal tilt angle for direct insolation (sunlight) appropriate to your location. Additionally, awnings may also serve the secondary purpose of keeping direct sunlight out of your home, thereby helping to improve the visual and climatic comfort for people inside.

Written by James Martin

Solar Choice Analyst

© 2010 Solar Choice Pty Ltd

Sources and Links:

Worker’s Health: Asbestos Factsheet

Thanks to the Greenwala.com Tech blog for the top image.

We here at Solar Choice are regularly asked about not only technical issues related to solar power, but also about which Installers are the most reputable and dependable. Even before considering these very critical points, there is the important issue of deciding if Solar Electricity is the right investment for your home and energy security. As a way to assist in this process we have formulated and answered 14 key questions for you to consider when deciding whether solar power is right for you.

1 What is your current energy usage?

Prior to going ahead with installing a solar photovoltaic system, it is very important that you are aware of your household’s energy consumption. You should be able to attain this information from your electricity bill, where this number will be shown in the form of œKilowatt-hours (kWh) or alternatively as œUnits. If this information is not stated, then contact your Electricity Retailer, who will be able to provide it to you. Once you are aware of your energy consumption, you can then compare this against the potential yield of a solar system: As a guide, 1kW of PV will generate 4kW of electricity each day “ but this will vary depending on your location, the position and orientation of the system on your roof, and the seasons. A Solar Choice Broker will be able to assist in sizing a PV system that meets your needs.

2 How quickly do you want to see a return?

Obviously most people will answer, “as fast as reasonably possible”. Most incentives in Australia are net feed-in tariffs, which encourage reducing the amount of energy consumed in order to widen the gap between what you produce and are rewarded for. A standard rate of return on a smaller system (under 5kW)is usually expected to be under 5 years. On a larger system (5-10kW) the expected payback period is around 5-7 years. Although the initial up-front cost is considerably more, the long term benefits of these systems far outweigh those of the smaller systems.

3 How much money are you prepared to invest (spend)?

One objective of investing in a Solar PV system may be to cover your annual bills or to at least reduce them. Some individuals simply want to get the most cost-effective system and keep spending to a minimum whilst still benefiting to some extent from the generous feed-in tariffs. Others may want to maximise available roof space and install as big a system as possible with the goal of generating as much electricity as possible. Your Solar Choice Broker will speak with you about your roof to determine just how many panels will fit. Solar energy conversion technology (photovoltaics or PV) has come a long way, and many are investing for sound financial reasons. Returns of up to 18% are achievable. Whatever your aim, Solar Choice will do their best to help you reach that target.

4 What Government rebates will you receive?

In Australia, there are two significant financial incentives for investing in a PV system and creating solar energy on your own home. The Federal Government is responsible for the Solar Credit Scheme, which reduces the full cost of the system and provides a generous point of sale discount. This scheme has been designed to taper off over time, so the sooner you purchase your system, the better.

Following success in countries such as Germany and Spain, various State and Territory governments in Australia have adopted feed-in tariffs. Under these state-by-state schemes, your energy provider is obliged to buy back the energy you export to the grid at a price equal to or above market rates.

5 Is your REC (Renewable Energy Certificate) discount locked in from when you deposit?

This can affect the price of the system significantly if it is not locked in.

This depends on which Installer you select.  A number of installers state in their Terms & Conditions that they will incorporate the costs of the REC whether or not this has increased from the time of deposit to installation. However, if this is not stated explicitly,  then it is something to consider as it can potentially affect the final cost of the system upon installation.

6 Why is this particular system being recommended to you?

Your Solar Choice Broker can discuss with you what system sizes and configurations are possible for your property, and what is available in your area in terms of Installers, panels and inverters, and financial incentives. You can discuss with them your energy usage and how much electricity differently sized systems can produce. Then, based on your budget and priorities they can provide you with a range of options. Ultimately, the choice is up to you.

7 Will the company quoting on the system also be doing the installation?

The answer to this depends on the individual company.  Some installation companies have teams of their own installers who are trained by them and work exclusively for them. Alternatively, installers may use sub-contractors who work for several different installation companies. Just because an installation company uses sub-contractors, this does not mean the quality of work is diminished.  One measure to check is that both the installation company and the electrician/sub-contractor are accredited and certified by the Clean Energy Council.  Generally, utilising sub-contractors allows a company to broaden its geographical reach and installation capacity.

8 Does the company have a proven track record in solar installations? Are they an accredited installer with the Clean Energy Council?

Just like in any market, different companies have different track records. Some have certainly been around for much longer than others. Your Solar Choice Broker will be happy to discuss what options are available to you if this is a priority. Solar Choice works with a network of installers, all of which are accredited with the Clean Energy Council, and is continually updating our knowledge base with market relevant information. It is important to keep in mind that Solar Choice provides impartial information, and is able to assist you with your research and due diligence.

9 Does the Installer use the correct DC cable rather than the AC cable?

The wrong cable can reduce power yield and reducing productivity by thousands of dollars over the lifetime of the system. This is a critical part of your system to ensure the power is used most efficiently.

This is something that the installation accreditation course covers in detail, so you can be very confident that your Installer will be using the right cable for the right position “ but it is worth keeping in mind. If you can ask a question like this of the installer, you should receive a good answer and respect.

10 Are manufacturer warranties supported locally and how are warranty claims handled?  What happens if something goes wrong with the panels?

As with any large consumer purchase, it is good practice to check who holds the warranties on the panels and inverters. For example, if the panels are held by the manufacturer (a company based in the Zhenxiang Province of China), it may be up to the customer to remove the panels from the roof and have them shipped to the manufacturer for testing, at their own expense. Preferably the warranties should be held by the installer who supplied the panels. This way, if something does go wrong the installer will be on hand to deal with problem.

11 How long will it take from from deposit to installation?

This factor will vary depending on your choice of Installer. Lead times between Installers can range from as little as three weeks up to four months. Typically, the shortest lead times are with local installers, while the longer lead times are with the larger, multi-state installers. Should you have any questions relating to specific installer lead times, Solar Choice will be able to provide that information for you.

12 How will the system be maintained?

With very little maintenance, your new PV system will to last up to 25 or 30 years.

There is very little maintenance associated with a grid-connected PV system. All you need to do is keep the panels free and clear of debris and dirt accumulation, and have the electrical system and wiring inspected by an electrician periodically. There are a range of system monitoring devices available.

13 What racking (mounting) will be used and what is the warranty on the racking?

Standard racking components generally consist of the rail itself (annodised aluminum) and fasteners (stainless steel). The rail is made up of various clamps, plates and brackets. The racking warranty is included in the Installer’s warranty and located within the Installers Terms & Conditions. As this is an integral part of the system, especially for high wind areas, it is worth asking the Installer for specific details about the racking that they use.

14 Does the racking use both mid- and end- clamps to secure the modules?

The most commonly used option is to drill into frame-work.

If a strong wind could potentially relocate your roof, then you have bigger things to worry about than racking. However, mid-clamps are one indication of a better, more stable installation, so it is worth asking your Installer if they use them. If you are told that they will cost extra, then ask them to tell you how much extra, and for them to justify the cost. Some Installers will use mid-clamps as standard, while others will view it as an optional extra.

In any case, going Solar is a long-term investment. Your system will pay for itself many times over the course of its life. Shortcuts may save money, but in order to maximise the results and returns in the long-term, don’t forget that quality counts!

Written by Sam Bradley, Justine O’Neill, Ella Vial, Tom Chapman, Matt Lasauce, Lydia Robertson, Alex Chiddy, Tom Charlesworth, and Rob Burnett

Solar Choice Residential Brokers

© 2010 Solar Choice Pty Ltd

You can check out more informative FAQs a number of our previous blogs by clicking here.

A great number of people throughout Australia are taking advantage of the federal government’s Solar Credit scheme, which offers financial incentives for solar power installations on their homes. Many people are also wondering if they can get additional Solar Credits for a second or third installation on the same property–like on the roof of a granny flat. This article will address the eligibility clauses to consider for such a prospect.

(Request a free solar quote comparison from solar system installers in your area.)

We here at the Solar Choice blog have previously written extensively about the Solar Credit scheme and Renewable Energy Certificates (1 REC = 1 megawatt of renewable energy), which are guaranteed at $40 (if you are willing to wait) as of January 2011.  For a general overview of RECs and Solar Credits, please see this informative article. We also have a great entry on how to calculate your Solar Credit discount, or you could go to the Office of Renewable Energy Regulator website and check out their handy calculator.

In a nutshell, Solar Credits are part of the Mandatory Renewable Energy Target program, or MRET, later amended to the Enhanced Renewable Energy Target or eRET, and in January 2011 divided into the Small-scale RET (SRET) and the Large-scale RET (LRET).  The program aims to promote the uptake of renewable energy technologies in Australia to 20% of all electricity consumed by 2020 by offering RECs, freeing up cash for investment, and other policy programs.

So, let’s say you already have a photovoltaic system installed on the roof of your main home and you’ve also got a granny flat with a bare-looking roof out the back, begging jealously to be decked out with some lucrative and environmentally friendly solar panels. Would it be possible for you to do so? The answer is essentially yes, as long as both the properties have different addresses. An address can be established quite easily from the address on the electricity bill, and all addresses with a different number on the street will certainly fall in this category. If the address is a sub-lot such as 3a or 6b Smith Street, then the eligibility is still open. However, different structures on the same address such as shearing sheds and homes on the same rural lot, will not be classed as different address. Be aware that this has nothing to do with the number of meters or sub-boards that exist between properties.

This Solar Credits FAQ gives a good overview of the REC scheme, including some additional details about the eligibility of solar installations for Solar credits. These limitations include:

-The system must be a ‘small generation unit’ with a capacity less than 100kW in the case of solar PV

-The system is installed in an ‘eligible premises’, including a house, a townhouse, a residential apartment, or a shop

-The installed system must be new, complete, and functioning.

-There can be no ‘double-dipping’.  That is, you cannot take advantage of more than one renewable incentive scheme.  If you you apply successfully for RECs, you cannot subsequently apply for benefits through the Solar Homes and Communities Plan, the Renewable Remote Power Generation Program, or the National Solar Schools Program.

Helping you decide how to get the most of an installation is what Solar Choice does best, so feel free to get in touch with us for a free quote.

Sources and Resources:

Australian Department of Climate Change and Energy Efficiency “Solar Credits FAQ”: http://www.climatechange.gov.au/government/initiatives/renewable-target/need-ret/solar-credits-faq.aspx

Office of the Renewable Energy Regulator homepage (ORER): http://www.orer.gov.au/

Written by:

James Martin

Master of Environmental Management, UNSW

Solar Energy Analyst

We get asked a lot of questions and sometimes the answers just remain on the page of the article and it is hard for others to keep track of them, so we have decided to summarize some of the key questions we have faced here is a summary of answers to frequently asked questions.

Why does pricing differ so much from one quote to another?

There are a number of factors that contribute to this disparity, and most of them are fairly common sense. Consider your options of installers to fall somewhere on a line with two extremes: large, national installation companies and local installers.

As a general rule, large companies streamline their business models and essentially offer less service with better prices. They do this by ordering components in bulk, large community promotions, linking together installations whenever possible, hedging a value on their REC’s and streamlining customer service. Local options spend more time in customer service and care, but offer more moderate to premium prices and products to distinguish themselves.

A quick note on product: Your local installer is aware that they cannot compete with the large companies on the competitive prices, so he won’t usually bother with the cost-effective panelling or inverters. The larger the company, the more they have the capacity to go competitive, and in trying to hit that market-leading price this will often mean more cost-effective components. This doesn’t mean they don’t offer premium component systems as well, so if this is where your interests are, be sure to check what options are available from all avenues.

The appropriate option comes down to your individual needs and expectations. The trick is to compare what you’re getting (product and service) with what you’re paying. Check the reputation of the components online and review the size and history of the company from their website. Don’t expect hand-holding from the national installers or rock bottom low prices from the blokes next door. Do expect to be treated fairly and honestly and that the product and installers are fully licensed, accredited, tested and approved by the International Standards IEC61730, as well as either IEC61215 or IEC61646. All installers on the Solar Choice network abide by these standards in all respects.

What products are proven beyond doubt to be superior and worth premium prices for?

Impartial advice is to not believe claims that any one product is the best. The vast majority of testing is subjective and the reality is that no panel has been tested where you are looking to install it; on your property.

i.e. Claim: ˜Panel X is the most efficient panel on the market’
Testing Conditions:

• Conducted at Latitude -31.802893, Longitude,146.777344;
• Operating temperature 35°C;
• ABC brand inverter;
• Pitch of 25°;
• Azimuth of 65°.

The only way that a panel or inverter brand becomes highly regarded is through decades of success on a technical and practical level. The brands that hold reputations such as this can be identified by speaking with your solar broker, or carrying out some quick diligent research on the internet.

As far as products to be avoided, so long as those international standards are in place and the product passed for use in Australia then you’ve done as much as is expected from a residential customer. Find the system that suits your budget and remember the diligent research that Solar Choice has carried out on all installers active on our network.

n.b. If you’re looking at commercial or industrial applications where a more in-depth and long term analysis of product is recommended, then our commercial tender managers can be contacted by placing an enquiry on our website via the standard sign-up process.

Why does the Solar Credits amount change from installer to installer?

The Solar Credits Discount Scheme is based on the total value accrued for the Renewable Energy Certificates (REC’s) generated for the project. Whilst the number of RECs stays the same from installer to installer for a project, the total value for the amount of REC’s alters based on what price they are sold for.

The RECs have a market value, but this fluctuates based on market trends. In addition to this, a number of installers, usually large national companies, trade their RECs via hedged price agreements with buyers, so they can actually sell their RECs for better than market rates. This is because they install so many more systems and obtain many more RECs, therefore exercising greater bargaining power on the market. These agreements are usually held in discretion, so don’t be surprised by the often confusing differences or lack of information disclosed by installers about their REC value.

For example: A 1.5kW system installed in Sydney (postcode-2000) generates 155 RECs.

1. A local installer’s quote, using the current market rate of $36 per REC, offers a Solar Credits Discount of $5,580.
2. A state-wide installer quotes, using their hedged price of $38 per REC, thus offering a Solar Credits Discount of $5,890.
3. A national installer quotes, using their discrete hedged price of $40 per REC, and thus offering a Solar Credits Discount of $6,200.

Is pricing going to increase or decrease in the near/distant future?

There are two different sides to this story, one much more persuasive than the other.

The argument for decreasing prices would highlight increased efficiency of trade lines into the country, component technology developing and reducing in price, installer competitiveness growing and REC value’s climbing.

The opposing argument needs only one of two points to trump all of the above. Basically, have no doubts that government incentives will decrease. This will mean more outlay, less return and less choice.

The Office of the Renewable Energy Regulator (ORER) moderates the discount schemes and ensures that the pricing remains competitive. They have the power to alter the discount and make it less effective when they see fit to ensure that pricing never becomes too cheap. They are considering a reduction in the number of RECs generated for residential installations before the end of 2011 in line with this.

In addition, the state governments all review the generosity of their feed-in tariffs and reduce them as time goes by in order to slowly ease of the pressure on energy wholesalers and retailers. As both of these incentives decrease in their value, prices will remain at least as expensive and more importantly, systems will earn less via a reduced feed-in tariff over their lifetime.

What is the difference between Monocrystalline, Polycrystalline and Thin-Film panels?

Monocrystalline will be completely knocked out by shade in most instances, and takes up about 8 square meters per 1kW. Polycrystalline is only slightly less efficient and usually cheaper so it can be a great option for a rounded system. Thin film will only suffer marginal and isolated losses to shade, and will take up about 12sqm per 1kW (50% more). Remember that if your panel is less efficient you just need more of them, so if your roof space is large enough don’t let these differences guide your decision.

What is the point of having a larger capacity inverter?

A larger inverter allows the system to integrate additional panels at a later stage. Therefore, larger inverters are only used for upgradeability purposes.

However, inverters work best when they are interpreting a voltage that is around their nominal output. The nominal output of an inverter is the figure that is detailed to you in quotes and in Solar Choice quote comparisons. Quite simply, it is the kW measurement of when the inverter is working at its perfect rate. If the output of the system (the total kW when adding all of the panels together) is far from the nominal output, the inverter will not work as efficiently.

From this, two deductions can be drawn. One, do not install a system where your output is much less than 75% of your inverters nominal output. Two, due to efficiency losses from a myriad of factors (y) such as dust build-up, cloud, not perfect orientation/tilt of the panels, your (x)kW system is actually going to be producing on average (x “ y)kWh a day. So the best system for your inverter actually has slightly more of a capacity to the panels than the nominal output of the inverter. i.e. a 2.2kW system with 2kW inverter. 10% is a wise maximum to consider along these lines.

How much roof space will my solar energy system occupy?

For flush mounted systems:

• Monocrystalline = 8 square meters per 1KW (10kW = 80sqm)
• Multicrystalline (Polycrystalline) = 8.5 square meters per 1kW (10kW = 85sqm)
• Thin-Film Amorphous = 12 square meters per 1kW (10kW = 120sqm)

For ground mounted or tilt framed system the difference is considerable, so better to enquire with us directly upon the specifics. Email sales@solarchoice.net.au or call 1800 78 72 73.

How do the REC’s work, and is anything required from me to receive the Solar Credits Discount?

Every year the biggest 100 polluters in Australia must account for their immense emissions by handing over a certain number of REC’s to the government. This number is proportional to the amount of pollution they produce. The REC’s are generated every time someone installs a renewable energy source in the country. The REC market provides an avenue through which the holders of these RECs can eventually sell them to the polluters to compensate themself for the price of installing the renewable energy source.

All of the complexity regarding REC market value, installer trading and hedged pricing agreements can be condensed into this one explanation: sell your RECs to your installer for a reasonable price and consider it as the polluters chipping in to pay for your solar/wind/hydro systems installation. Do this by following your installers’ instructions and filling out the forms they provide you. That is all you need to do to claim the Solar Credits Discount.

Why is a tiled roof or a double storey installation more expensive?

Colourbond and steel rooves are simple for solar energy installations. The installers can simply screw the racking straight into the material without compromising water or structural integrity. However, tiles are brittle and would break under similar treatment. Installers therefore must screw racking into the material underneath the tiles and replace them carefully to preserve the roof’s reliability. This should cost you between $100 to $200 and is a completely understandable and justifiable expense.

Double storey rooves require extra safety equipment and precautions to be used by installers. This is for OH&S reasons primarily, so having easy access does not affect this at all. It should usually cost $200-$400 for this charge, and again, it is completely justifiable.

How many kWh’s will my system produce per day?

Across the latitudinal lines in Australia and on average:

• Brisbane and above: 5kWh per 1kW system per day
• Between Brisbane and Adelaide, including Perth and Sydney: 4.5kWh per 1kW per day
• Melbourne and Hobart: 4kWh per 1kW per day

This is the most helpful and accurate guide to the number of kWh per 1kW system installed we have found. It assumes the system is between 80%-100% efficiently positioned:

http://www.solar4power.com/solar-power-global-maps.html

What do the different warranties (performance, manufacturing and installation) encompass?

Performance warranty is 25 years minimum for approved systems and only applies to the panels. It refers specifically to the gradual degradation of the solar cells in the panel. This usually accounts for a 10% drop in output due to this degradation in the first 10 years, and a further 15% in the latter 15 years. Some panels perform up and above this standard.

Warranty on manufacturing applies to both the panels and the inverter and involves any aspect of the manufacturing that if performed incorrectly could affect performance. Imagine for instance that one of the connector ports for the leads between the panels was not screwed in properly by the robot/manufacturer, and this resulted in a loss of output from the system. This would be a typical manufacturer’s warranty issue. Minimum for panels and inverters is usually 5 years.

Installers warranty applies to any aspect of the installation that if incorrectly performed would result in performance losses. If an installer dropped a panel off the ladder when installing the system for instance and this damaged the framing affecting performance, this would be an installer’s warranty issue.

As you might imagine, the vast majority of issues regarding both manufacturing and installer’s warranties would become obvious within the first year of the systems performance. It is for these reasons we don’t recommend customers becoming too concerned about the small differences in these warranties when deciding on their appropriate solar quote. Consider the warranties, but again don’t let them drive your decision.

What has to happen with the relevant electricity meter upgrades, and who is responsible for this?

This depends primarily on your solar installer and their integration of this process into their business models. Most installers will assist you with the forms and guide you through the process, but once your system is approved by your wholesaler you will be responsible for booking in the meter install with a level 2 qualified electrician. This is not an overly painful process and will cost you from $250 to $500, depending on the complexity of your meter box. On the other hand, some installers will take care of this whole process for an extra fee of the same amount. Finally, we have installers that include the price in their quote, and whilst they are rare, the extra service can be a load of your mind.

Do any of the installers offer finance?

Yes, simply ask your solar broker about which ones and what sort of arrangements they provide.

Are the economic benefits of the system taxable?

For all residential installation the system is not taxable. The only aspect of the systems operation that must be claimed is if you are sent money from your provider for surplus and are claiming a pension or Centrelink allowance of any kind.

For all commercial and industrial installations that involve installing a system on a business, every aspect of the system is taxable:

• The GST can be claimed back for the system, further reducing the cost;
• The income earned from the system must be claimed
• The system can be depreciated over 10-20 years depending on the outstanding ATO ruling.

How much money will my system make me? What calculations are used to work this out?

It all comes down to the feed-in tariff that the system is connected under. This rate differs from one state to another and also via the electricity providers. The big difference is between the Gross states and the Net states and the rate being paid.

Gross States: Simply multiply the amount of energy that is expected to be generated by the system per day by the rate your provider is paying and you will have your average daily income.

Example of a 2kW system installed on home in NSW

Assumptions: AGL is the electricity provider, currently paying 8c over the 60c gross rate minimum. Usage of the property does not affect return as this is a gross state.

2kW x 4.5kWh per 1kw per day = 9kWh generated from solar each day
9kWh x 68c (rate paid under gross tariff by AGL) = $6.12 per day

Net States: This is more complicated. You must establish how much energy is going to be generated by the system, minus off the daylight hour energy usage, then multiply the surplus by the tariff rate. The units from the solar system used up by the property still save those units from being purchased from the grid, so they add marginally to your economics

Example of a 3kw system installed on home in SA

Assumptions: The house consumes 5kWh over the sunlight hours each day. Origin is the electricity provider, currently paying 6c over the 44c net rate minimum.

3kW x 4.5kWh per 1kW per day = 13.5kWh generated from solar each day
13.5kWh “ 5kWh = 8.5kWh in surplus, and 5kWh saved from being purchased from the grid
8.5kWh x 50c (rate paid under net tariff by Origins) = $4.25 per day and
5kWh x 18c (Market rate for electricity purchased from grid) = $0.90

Total earnings from system per day: $5.15

Are the Australian, German or Japanese panels justifiably more expensive than Chinese panels?

At the end of the day, there are differences between panels. The international standards keep everything in the same ballpark, but panels and inverters will still outperform others in time. Take the stress off yourself and contact a Solar Choice broker if this is one of your more pressing matters. Think about your priorities, identify them, email us (sales@solarchoice.net.au) and let us make a suggestion that is appropriate for your project. It’s that easy.

How much efficiency do I lose without tilt frames?

You will lose between 15-30% of total output each day. This amount is significant, which is why tilt frames or alternative flat-roof designed systems are recommended. Remember that most city councils are far stricter on the need for Development Applications when panels are not flush mounted to roofs. If you have a flat roof, contact us and we will run an analysis on whether tilt frames or flat-roof designed options suit your project more appropriately.

Are panels hail proof?

All panels that hold the international standards (which they all do in Australia) have been tested to hail and impact damage. A one in a thousand year event will still damage them, but the standard hail storm has been tested against and the panels hold up fine.

Does the inverter need to be near the meter?

It is recommended, however, the inverter will be positioned on site in the most appropriate place. This may be a garage, laundry or meter room. The distance between inverter and meter should not exceed 20 meters to avoid transmission losses.

What happens if one of my panels is in shade?

It will stop working. It may knock out all other panels in the ˜string’ as well. Depending on the size of your system, this can mean huge losses in output. Always avoid shading completely, and if you cannot, contact your Solar Choice Broker for advice. Thin-film panels are more shade tolerant, but the system will face losses regardless. If you have only got a heavily shaded area, just like if you’ve only got a South facing roof area, then solar energy is not recommended for you.

Will it work if I have panels on more than one side of the roof, and how?

Usually it is only recommended to split the system up over multiple roof areas if you have an inverter that can read the arrays separately, all aspects and tilts are identical, and none of the areas are subject to shade. Inverters that have Dual Tracking (Dual MPPT inputs) allow panels to be split over two completely different areas; however these are usually more expensive. Please note that MPPT Tracking is not Dual Tracking, and most inverters had one MPPT Tracking listed on their technical specifications. Only a Dual-input MPPT inverter can split the system independently.

Written by Jarrah Harburn

Senior Solar Energy Broker

Solar Choice

© 2010 Solar Choice Pty Ltd