Duxa:
There's made up numbers and then there are other made up numbers. Without seeing warranty claims and numbers, you have no basis for being sure of anything. Without understanding ways performance can deteriorate, you have no way of knowing if a performance deterioration rate is reasonable.
If a panel that's on you property experiences an output or efficiency drop over a period of time, how will you even know it, much less go about verifying such a condition ? Well, as a consumer, you won't in any reliable and repeatable way because you, I and every other consumer cannot even reliably measure input, or even understand it, much less deal with the intricacies of PV output and measuring it and then putting all that together and come up with an efficiency drop.
If you think you can do all that - accurately - please enlighten us all how you would go about it.
Believe what you want but if you think you can, you are mistaken. Additionally, since you need a measure of input as accurate as output, you and most every other consumer do not have access to the type and quantity or quality of historical meteorological data including site measured irradiance necessary to measure and so verify an efficiency drop.
Then, there's the whole question of measuring and recording how dirty the panels have been, how often they were cleaned and how effective any cleaning has been. Data of all such things will be necessary for any successful performance warranty claim.
Point is, while it's not necessarily a made up number, performance degradation is more an estimate based on lab measurements and projections based on accelerated aging rates and other methods than a hard number that's been field verified under varying conditions.
The main and probably only reason for things like production guarantees is for marketing. Mfgs. know more about performance degradation then most any consumer and they know verifying a performance warranty claim in the field is next to impossible, even with a lot of knowledge and equipment. So, they get to say pretty much what they want knowing performance will almost never be checked in ways required for a successful performance warranty claim.
Well intentioned but very uninformed folks like you drink the Kool-Aid marketing hype and greenwash media garbage thinking a premium paid for a panel will get extra performance and more reliability. The reality is something different. Folks who have been around for a long time with more experience and education than you know this and also know that beyond a certain level of basic quality and Q.C. panels are mostly a commodity.
Take what you want of the above. Scrap the rest.
There's made up numbers and then there are other made up numbers. Without seeing warranty claims and numbers, you have no basis for being sure of anything. Without understanding ways performance can deteriorate, you have no way of knowing if a performance deterioration rate is reasonable.
If a panel that's on you property experiences an output or efficiency drop over a period of time, how will you even know it, much less go about verifying such a condition ? Well, as a consumer, you won't in any reliable and repeatable way because you, I and every other consumer cannot even reliably measure input, or even understand it, much less deal with the intricacies of PV output and measuring it and then putting all that together and come up with an efficiency drop.
If you think you can do all that - accurately - please enlighten us all how you would go about it.
Believe what you want but if you think you can, you are mistaken. Additionally, since you need a measure of input as accurate as output, you and most every other consumer do not have access to the type and quantity or quality of historical meteorological data including site measured irradiance necessary to measure and so verify an efficiency drop.
Then, there's the whole question of measuring and recording how dirty the panels have been, how often they were cleaned and how effective any cleaning has been. Data of all such things will be necessary for any successful performance warranty claim.
Point is, while it's not necessarily a made up number, performance degradation is more an estimate based on lab measurements and projections based on accelerated aging rates and other methods than a hard number that's been field verified under varying conditions.
The main and probably only reason for things like production guarantees is for marketing. Mfgs. know more about performance degradation then most any consumer and they know verifying a performance warranty claim in the field is next to impossible, even with a lot of knowledge and equipment. So, they get to say pretty much what they want knowing performance will almost never be checked in ways required for a successful performance warranty claim.
Well intentioned but very uninformed folks like you drink the Kool-Aid marketing hype and greenwash media garbage thinking a premium paid for a panel will get extra performance and more reliability. The reality is something different. Folks who have been around for a long time with more experience and education than you know this and also know that beyond a certain level of basic quality and Q.C. panels are mostly a commodity.
Take what you want of the above. Scrap the rest.
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