I’ve had my Solar Panels for 6 years now, and annual generation has been pretty consistent until this year. Interestingly I’ve noticed over the last year that the number of clear sunny days has reduced, and therefore I can mostly exclude reasons such as Inverter issue, or dirty panels (they still look clean).
The break down of changes compared to previous Month shows us where this 10.1% has gone, but the numbers are all over the place to get any real conclusion.
I’ve only had my panels for 18months, so can’t comment on long term generation.
Though I’m very surprised how consistent 2019-2023 was. I’d expect a +/-5% at least.
Do you have panel monitoring, such as SolarEdge? Maybe something useful can be extracted.
Those first five years are incredibly consistent and to see a sudden drop is strange. Maybe one or two of the panels has become disconnected. Our 16 panels are wired as three of four groups, so if sat two or three of yours are wired together, a disconnection would explain it. There should be a menu in the inverter that will show you what’s happening. Possibly.
No I don’t have that. Most my various stats are taken by taking reading every month, and the generation is from the FIT meter, so very accurate
@HungryHalibut my panels are in two groups of 9, so I may be able to get those stats, however it has seemed like sun levels have been lower this year. 10% reduction would suggest 2 panels. However once you have had panels for a while, you do start to watch the weather a lot more, and you eventually get a feel for what they should be producing, so in my head, it’s a weather issue rather than a technical issue. Anyway I will see if I can get any stats, although unfortunately the original app used was retired a while back, and in transferring over it lost the history, so it may be limited
Tell me about it! We’ve made 5.5kWh so far today. Our best day was 8.2. Since turning them on on 20 December we’ve generated 156kWh. It’s been interesting watching production tick up a little as the days lengthen. On some mornings the heat pump runs entirely from solar, which is lovely to see.
Yes, it becomes addictive - it drives my wife mad sometimes. Not having batteries makes it worse, as you find you are looking to see where the clouds are for best timing of usage (although I do get a sense of satisfaction about it). I have now recuperated 92% of the cost so happy with that.
Just checked the two panel groups, and they are pretty similar, so that’s good news, but also a worthwhile check, thanks
My 2024 output was down about 8% or 9% compared to 2023. June 2023 was a very good month, with 980 kWh. I have 16 panels split over two roofs (11 and 5). While my panels are 420W DC, each has a 300W AC microinverter. So each panel generates independently. That is, there is no string inverter. Yes, there is an initial cost, but I’m still surprised they are not fitted as standard now. Anyway, as noted, my output was down in 2024, with July being particularly poor.
Panels 6002 in year from 30 Jan 2022 (day 1) and 5500 upto today. So 8.4% down. There will be less AC from inverter. I have 15 panels of 420W with SolarEdge string inverters on two strings. Roof faces 160 degrees so nearly south. The neighbours although 30-40m away to the south do shade until 9am at this time of year. We are a chalet and they are 2 storey.
206kWh DC from 20 December with a peak of 14.55 on 9 Jan and just a bit less on 25th.
I’ve had PV for 12 months so no comparison, but the level of cloud cover has certainly been high this year. July was particularly poor, worse than August which should of course have been the other way round.
I do wonder whether installers have adjusted their indicated generation based on the changes over the year as it could completely mess up recuperation stats.
No solar panels here, but as others mentioned quite amazing you had little variability in earlier years. I think I’d just put it down to natural variation at the stage, and accept there’d be a mix of good and worse years.
How soon do the panels degrade and become less efficient?
I’d really love to have solar as we are heavily electricity dependent currently but I really can’t get a feel for cost/benefit of fitting and length of return to break even.
I suspect they can all vary, but I found this. degradation rates of solar panels are estimated at 0.5% per year
They are supposed to have a lifespan on 25 years plus
But as mentioned, it’s felt like a sun-less year, and other peoples experience seems similar.
The figure I’ve seen is 1% per year, but apparently the degradation is not linear.
Still, if you’re still alive and living in the same house in 25 years time it might be reasonably cheap and easy to swap the panels, although the inverter may well have a shorter lifespan.
This would distract me to no end, as well. Also, in Canada here, I just don’t think there is enough sun all year to do the trick.
With that in mind, I have pretty much decided that when we move house in 2025-2026, I will get a full home, battery backup system, wired into the panel with a very small auto-start, natural gas generator to trickle charge it when the power does go down.
The generator would not run continuously as the battery units have a overcharge safety built in.
My research so far has been very positive and the hardware cost seems to be around 10-12k CAD. There would be labour for electrical connections, so 15k should do it. These batteries are good for 4000 charges.
I believe this will put my costs at less than a solar setup, at least at Canadian prices.
Just to clarify, my thought here is that after pricing out panels, switches, a large (Tesla?) battery, and install, I thought of just bypassing the solar and going right to a good battery backup.
And I’m thinking that that bit of natural gas and even some grid power used for trickle charging the batteries will be a lot less cost than full grid power, and also give us full home power during a power outage.
I still have some investigating to do to prove this out.
