New testing conducted at France's oldest PV system have shown that its solar modules can still provide performance values in line with what the manufacturers promised.
They work fine, just not at full capacity. Financing and payback calculations tend to assume they’ll be replaced after 30 years, but that’s just guesses made by accountants, not reality.
Similar holds for EV or phone batteries. They usually don’t suddenly die, but lose more and more health over time. Realistically, you have to set a threshold, where you call it no longer useful.
If the life expectancy was 80%, then we’ve passed it and they are due for replacement. If it was 70% the they still have years of useful life.
It’s probably one of those two. For phones, I replace batteries when health drops to 80%, because I spend too much of my life online. Also, I’m probably giving my phone to my kid about then, so they deserve a fresh battery. I have kept phone batteries down to about 70% life, but then it usually doesn’t last the day and I’m carrying portable chargers everywhere
I haven’t had an EV long enough but I believe the typical battery warranty is defined like that: not just that it’ll work for 10 years, but that it will still be at least 70% health after ten years
I thought that solar panels that old performed much worse or stopped working. Especially considering where the tech was in the 1990s.
“performed much worse” is compared to today’s manufactured panels. As an example, a 100w panel in 1992 was likely around 12% efficient. This means “of all the light energy hitting the full panel under perfect light and temperature conditions”, 12% of that energy is converted to electricity and would produce 100w. Compare this to a middle-of-the-road panel you’d buy for your house today the efficiency is 21%. Both the old and the new panel’s efficiency will go down over the years.
What the article is talking about is how much of the original efficiency is retained over the years in real world tests. Lets say we have a 1992 100w panel from my example above at 12% efficiency. That means under the best possible conditions it would generate 100w. Because of age, the article notes that efficiency has degrade to produce 79.5% of its original rating. Meaning this 1992 100w panel today would generate 79.5w. That’s still pretty darn good and useful!
One other point I see I left out was physical size of panel as related to efficiency of converting light to electricity and the reason that 2024’s 22% efficiency is so important over 1992’s 12%. The 2024 100w panel will be about half the size of the 1992 100w panel. This is important because space to put panels (and cost per panel) are large factors in being able to install solar. So you’d be able to install many more 2024 100w panels in the same space as 1992 100w panels.
I thought that solar panels that old performed much worse or stopped working. Especially considering where the tech was in the 1990s.
They work fine, just not at full capacity. Financing and payback calculations tend to assume they’ll be replaced after 30 years, but that’s just guesses made by accountants, not reality.
Similar holds for EV or phone batteries. They usually don’t suddenly die, but lose more and more health over time. Realistically, you have to set a threshold, where you call it no longer useful.
If the life expectancy was 80%, then we’ve passed it and they are due for replacement. If it was 70% the they still have years of useful life.
It’s probably one of those two. For phones, I replace batteries when health drops to 80%, because I spend too much of my life online. Also, I’m probably giving my phone to my kid about then, so they deserve a fresh battery. I have kept phone batteries down to about 70% life, but then it usually doesn’t last the day and I’m carrying portable chargers everywhere
I haven’t had an EV long enough but I believe the typical battery warranty is defined like that: not just that it’ll work for 10 years, but that it will still be at least 70% health after ten years
There is a solar plant in switzerland that still has functioning panels from the early 80s.
“performed much worse” is compared to today’s manufactured panels. As an example, a 100w panel in 1992 was likely around 12% efficient. This means “of all the light energy hitting the full panel under perfect light and temperature conditions”, 12% of that energy is converted to electricity and would produce 100w. Compare this to a middle-of-the-road panel you’d buy for your house today the efficiency is 21%. Both the old and the new panel’s efficiency will go down over the years.
What the article is talking about is how much of the original efficiency is retained over the years in real world tests. Lets say we have a 1992 100w panel from my example above at 12% efficiency. That means under the best possible conditions it would generate 100w. Because of age, the article notes that efficiency has degrade to produce 79.5% of its original rating. Meaning this 1992 100w panel today would generate 79.5w. That’s still pretty darn good and useful!
Great explanation.
One other point I see I left out was physical size of panel as related to efficiency of converting light to electricity and the reason that 2024’s 22% efficiency is so important over 1992’s 12%. The 2024 100w panel will be about half the size of the 1992 100w panel. This is important because space to put panels (and cost per panel) are large factors in being able to install solar. So you’d be able to install many more 2024 100w panels in the same space as 1992 100w panels.