We get hundreds of people enquiring about buying solar power systems who claim they will happily pay more for German panels but none of them seem to have a clue why?
Presumably they would only be prepared to do so if they were convinced either that the solar panels would produce more power initially, or the rate at which their power output would decay over time would be better with the German panel than an equivalent Chinese panel.
So does a German solar panel produce more power when turned on new?
The answer is no
Claims by those trying to sell German made solar panels for high prices don’t survive a basic logic test on this point. When a solar panel is made, all solar panels that is, they come off an assembly line, have 1000 mega joules per sqm of irradiation fired at them at 25 degrees and the amount of power they produce is recorded. If they produce 230-242 watts then they are marked as a 230 Watt panel whether they are made in Germany, China or Timbucktoo.
There is no way that some of the claims made by those selling German made panels, that they produce 20% more power, can be true because the German Solar Panels own spec sheet says it is 230 watt with a positive tolerance of up to 5 watts (or 5% in some cases which is 11.5 watts on a 230 watt panel), the same as what the spec sheet for the equivalent Chinese module says. It would be against the law and international electrical standards to quote a specific range of power output, say 230 watts for a panel if actually it produced meaningfully more power than this.
What I notice about these claims is that they are never made by the German companies themselves these claims are always made by middlemen and distributors and usually made verbally with no written guarantee to this effect. Don’t you think if a German company had a 230 watt panel that produced 20% more power than Sunrise or Trina’s Chinese made 230 watt panels they would have documented this, and in any event they would then legally have to sell it as a 280 watt panel if it did.
Does the power output of a German solar panel decay at a slower rate such that over 25 years they produce more power than a Chinese panel even if the two panels produce the same power initially?
I have not seen any evidence that this is true but similarly it is not really possible to disprove it without a crystal ball that looks 25 years into the future.
The only evidence we can take is side by side comparisons where German panels are in the field alongside Chinese and other panels. In Australia we have the government funded Desert Knowledge Centre near Alice Springs, (not the ideal spot for this as the climate around Alice Springs is nothing like the prevailing climate in most of the major population centres of Australia) but nonetheless the best data we have for an independent side by side comparison.
The graph below shows the average power output from four different solar panel brands installed at the Desert Knowledge Centre. The panels are the German made Q-Cells mono crystalline solar panels, the German made Q-Cells poly crystalline solar panels, a Chinese brand called REC and a Tiawanese brand. These panels are probably 2-3 years old now and the result. Suprise, suprise all four brands produce and almost identical amount of power. In fact the lines on the graph are so close together that it is hard to tell we are actually tracking the production of four separate types of panels.
Now inverters are a very different story. In our experience it is worth paying a little more for a top quality inverter and in our experience the most reliable inverters are the German made SMA Sunny Boy inverters. We are not against paying for quality we are just against other companies using unsubstantiated claims and fear tactics based on lies to get people to spend thousands more on a solar power system than what they have to.