There is a lot of competition in solar right now. What we often see in the market are people trying to compare systems. The tricky thing with solar is that there is rarely an “apples to apples” comparison.
Basically what goes into a system are:
- Balance of system (frames, wiring etc).
- Qualitative factors: the value of the ongoing support for the system + service received from the installer
The easiest things to compare are the first 2 aspects – panels and inverters, so therefore that is what most people do.
There’s dozens of inverters on the market (SMA, Xantrex, Samil, Power One, Diehl, Sharp, Growatt… to name just a few). These can be compared of course, although some suppliers offer different warranties as standard (and some installers pay extra and offer customers longer warranties too… for example many brands can have a 10 year warranty purchased. In a few cases even a 20 warranty can be purchased).
Panels are the area that has the most confusion. People look at the basic specifications – for example the output capacity – 190w, 200w or 250w). Panels also seem to offer the same warranties – a basic product warranty of 5 years (Suntech just increased theirs to 10 years) and an output warranty which is expressed in terms of the known deterioration (say 10% at 10 years and 20% at 25 years). These are always listed on data sheets, and seem factual. The problem with these is that almost noone has been making panels long enough to actually know what will happen. Even Suntech – the world’s largest manufacturer has just celebrated its 10th birthday! However, we take some confidence from the accelerated testing that some panels go through. (See my notes on Suntech testing on this same website).
Here’s something scary though. Most panels will not last anywhere near as long as promised. In tests from Suntech on panels published (anonymously, so we don’t know the brands) out of six types of crystalline panels, only two lasted the equivalent of 25 years. 2 lasted about 20 years and 2 lasted about 10 years.
Lifespan of panels
This is for a range of reasons including the quality of the cells, the quality of the electronics and the quality of the lamination and assembly. It seems that at each stage there are a myriad of things that can go wrong, and many new manufacturers are making these mistakes. The impact of these mistakes won’t show up for a few years… by which time your installer may or may not be in business, and the panels may not be covered by a warranty at all.
LJW Solar uses Suntech panels because of their quality control systems and local support here in Australia. There are several other Tier 1 brands, then literally dozens of Tier 2 brands. There are savings possible with these Tier 2 brands, but the question is – is it worth it?
Balance of system and installation
This is where specifications are almost impossible. Noone even asks what rails and wires are used, but these are critical. There are hundreds of cases coming out where systems have been installed by unqualified installers (there is a report on the ORER site of one company that had 705 instances of installs done without a Clean Energy Council certified installer on site). This again saves money for the client, and is often reflected in a cheaper system. These issues will take a few years to surface.
For a variety of reasons, many solar installers are going out of business. The main reason is that the companies are new and they just started to take part in the ‘gold rush’ of solar which began in 2009 and 2010. Now that the industry has calmed down, they are packing up or being shut down. Many others have been stung by the decrease in STC values – they offered customers anything up to $40 per STC as a point of sale discount (a 1.5kw sytem generated about 150 STCs, so theoretically a $6000 ‘rebate’) and the value subsequently fell to as low as $16 which meant for some installers… business killing losses.
What this means is that those suppliers who were the cheapest on the market will often not be here when you need support. For some, this is a risk worth taking…
When people are looking at systems they usually look at the system size as the main specification ie a 1.5kW system, and 3kW system and so on. What this doesn’t cover is that there can easily be 10-15% difference in system output. Over the life of the system this can be worth thousands to you. The bigger the system, the bigger the system.
In oversease markets, systems are often sold based on their output over a period of time, rather than their capacity. In more sophisticated markets - such as commercial sales – output is far more important that the stated capacity.
A great example of where specifications fail to highlight true qualities would be in cars. If you compare the specifications of two vehicles – say a Toyota Hilux ute and new Great Wall ute, you might be able to compare engine size and so on and think they were the same. A few years of ownership will probably show up the differences…
If you are looking at systems, especially if you are investing for the long term, look beyond the specs and make sure you buy quality not just numbers.
What makes a module durable
Panels still producing 93% after 12 years