Is now the time to buy a solar panel system, or is the rate of increase of solar efficiency going up fast and I should wait.
I want to know how solar panel efficiency has changed. If you are like me watching your two year old computer become antiquated after spending $1,000 on it is not fun, I don’t want to see this happen to a solar system I might pay $35K for.
Solar panel efficiency is the transfer rate from the sun’s energy turned into electricity. Or if you like Wikipedia’s definition:
“A solar cell’s energy conversion efficiency, is the percentage of power converted (from absorbed light to electrical energy) and collected, when a solar cell is connected to an electrical circuit.”
So I figure I need to see a chart of the efficiency over the last twenties years to see what the trend is like. If I find that the efficiency is doubling every two years I know that solar panel I purchase today will not be worth much in a few years.
I found a chart on Wikipeadia below.

From what I can tell the most common solar panels are the Cyrstalline Si Cells. I can see that the trend is not to double every two years, at least not lately. So this confirms if I purchase solar panels now, I can feel pretty good that they will not become obsolete like my computer in 2 years.
Update: Looks like solar panels can be like computers, 40% efficiency might have been reached.

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2 users responded in this post
be sure you’re comparing apples to apples when looking at effieciencies. Cell eff and Module eff are two different things. The difference being the losses resulting from encapsulating the cells into a mudule. The “clear” top sheeting isn’t exactly clear (resulting on losses), the traces on the cell block sunlight (more loss) and stringing cells together results in higher terminal and line currents (if/when paralleled) resulting in greater resistive losses. Point being, the chart above is “Cell” efficiencies, don’t expect to see modules quite that high. Although the overall trend will be the same.
[...] Jaxsun however pointed out from the previous post that this can be misleading since this is on a cell level and not on a panel level (panels have loss). [...]
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