Who is interested or has interesting data (min. 7-10 years) concerning the decrease of efficiency of photovoltaic panels over time? Help and comparison as well as methodology is welcome...
Dear Sir,
the degredation of the PV panel is increased in hot climate than the cold climate , from the experimental investigation we observed the degredation of the final energy yield decrease about 10% in compare with the newesst PV panel after 9 years of operation (the type of the PV panel is HIT PV Solar panel) and our climate is very hot in summer since the temperature of the PV panel reach about 90C in midnoon of the days of july and august.
Regards
According to Shwan, the solar industry standard is a conservative estimate of 3% in the first year and less than 1% per year after that. However, solar panel manufacturers are starting to realize that this is too conservative, and they are beginning to warranty their panels: less than 3% decrease in the output the first year, and about 0,5% decrease per year after that for most panels.
It would be interesting to know what processes in practical applications cause this effect. I doubt if it is a property of the cells as they are basically crystals and providing they are not subjected to extreme stress, thermally or mechanically, should be good for tens of thousands of years. Find a 'steam age' integrated circuit made in the late 1960s - I will warrant that unless it has actually failed due to misuse, it will still meet all of its electronic specifications. The biggest problem in my view are the interconnects between cells, which 'dry out' over periods of years and becoming increasingly resistive, additionally the panel supports may corrode, causing cells to displace and straining or fracturing the connections.
The degredation percentage differs from technology to another, for thin film technology like CIGS PV Panel will be more than crystalline Si technology and I agree with above comment by Mr. Tony
Yes, Naseer, of course, thin film cells will be far worse than fully crystalline ones. Their advantage might be if they can be made monolithic so the interconnects are inside a very robust environmental shield. But such an arrangement still has to be connected up externally, and this might actually be less reliable than stringing silicon cells together.
Gentlemen,
thank you for an inspiring discussion.
1. What kind of metoodics do you use to calculate the PV efficiency drop? According to my calculations, the degradation of the panels at our PV plant is approximately 10% in 6 years. (Calculated from total annual production recalculated to hours of sunshine - Central Europe).
2. The question is whether and how the transparent glass surface that protects the cells contributes to the decrease in efficiency. The quality of glass, the formation of micro-cracks and fouling have certainly some impact. In this context, the question of the importance of panel maintenance (cleaning) arises, which is often underestimated.
It is an interesting question and a fruitful discussion. As you know solar photovoltaic production and degradation due to ageing is geographical site specified. The location environmental parameters have the main impact on the ageing. Also, PV technology, system connection and load have an impact on grading. Tile now the PV manufacturer has approximation which sometimes over or underestimation of the degradation. I advise checking the ageing mainly based on the type of PV technology and environmental parameters in the location.
Dear Mr. Adam to measure the degredation percentage, U can measure the power peak of one PV module as a sample which operated in the field for many years under standared condition (STC) by using solar simulator system in labratory and compare the result with the value which is recorded in nameplate where fixed on backside of the module, the difference between the two values acts the degredation value.
Regards
Hi
What are the most important factors affecting the age of the solar panel, and are they similar in cold countries and warm countries?
Dear Mr. Naseer K. Kasim,
Thank you for your ideas. I understand measuring in laboratory conditions; however, I am interested in calculation and estimation from real production data in-situ during the operation period.
Dear Mr. Fadhil M. Oleiwi,
most important factors affecting the ageing of the solar panels are apparently:
· Climate and geographical conditions (temperature, humidity)
· Air pollution (dust, acidity)
· Technology and quality of panels
If can anybody provide more specific info, you are welcome…
Dear Mr. Adam,
Thank u for your interested comments and I would like to add another important factor which relates to the type of the PV Solar system will be used, in Off-Grid system the output voltage of the solar panels dont exceed than 100V (low electric field), but in Grid Tied PV Solar system (On-Grid) the output voltage of each string may be reach (500-1000V) which it considered high electric field will applied on the last group of the PV modules in each string (series connection), with hot condition (high module temperature) will acts these two effects together on increasing the degredation of the PV modules especially the tedlar(Polymer) layer which is existed in backside of the module that insulate the solar cells contacts from Aluminium frame which connected to the grounding system, this effect is called PID (Potential Induced Degredation).
Regards
Dear Dr. Fadhil,
U can see the last comments from Mr. Adam and my addition.
There is a big difference between the PV modules working in cold and hot climate, sure in hot climate the degredation will be more according to thermal stresses which produced from arising the module temperature to high value may be reach more than 90 degree in some regions over the world, for more details U can go back to the comment of Mr. Tony
Regards
Adam Pawliczek, here I share a methodology to calculate PV efficiency at any lifetime.
Article Estimation of energy efficiency in solar photovoltaic panels...
we are also concerned this parameter in project case study;
as above experts explained, it varies according to different technology and locations, while we desperately want to know a proved range of past implementations, it's said to be 20-25% efficiency loss over 25 years. though not sure the actual result.
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