Solar panel production figures

I can see some have had a nice day well not down hear in Devon its been dark and raining most of the day and I don't know how but we managed to make 13Kwh on this fine summers day
 
I've worked out I'm nearly 50kwh down on last month already and we are only at day 5! The start of June wasn't exactly great either.

The next few days don't look particularly stellar either currently forecasted at:
40
37
22
34
28

I know these will shift around a bit but they been pretty consistent as they have come closer to the present day. I'll be a lot further down on June if these numbers come true!
 
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Seeing Outputs in perspective.

I have data going back to October 2011. Last June was really good.

Just looking at the month of June, here are the results in order with the percentage achieved of the month's target

June 2023 117.54%
June 2014 109.83%
June 2018 107.97%
June 2024 106.43% (see note)
June 2015 104.10%
June 2017 102.28%
June 2022 100.71
June 2013 96.97%
June 2020 95.39%
June 2019 89.96%
June 2021 86.29%
June 2012 81.64%
June 2016 77.99%

Back in 2011 I was struggling to come up with targets. My SAP figure was hopelessly low and repeated on the EST (energy saving trust) website. Just now, the EST was still predicting output of 900watts per year for every 1kw installed on our south facing roof with no shade. Currently my output meter reading is 55075. It is mega unlikely that it will be any less than 56250 by the end of my year. Over 13 years, that is an average of 1083 watts per year for every 1kw installed, or 20% more than the EST currently predicts

In 2011, I trawled about and found a couple of experimental schemes and used the data from these to break down my yearly target into months.

Two things became clear. The predicted output was over 20% lower than my output. The data reflected a national average, but on the south coast where I live, output in the 6 winter months is much higher than the average and that summer output was lower. I tweaked the targets over the first 3 years and applied them retrospectively. For the most recent year which goes from October 2023 to October 2024 I have reduced my targets by 6% to reflect the drop in performance in my panels.

My best ever month was May 2020 when I achieved 132.51% of target . This was during lockdown. If I consider the day to be very close to "as good as you can expect" it gets changed to red. In May 2020 I had 13 red days. For June 2023 this was the best ever with 16 red days.

The air temperature has a strong effect on performance. Back on 16th July 2022 output was 83,6kw. The next day it was down to 76.2 and my comment for the day was "very hot". On the 18th output was down to 71.9kw and my comment was "even hotter". The following day output was down again to 70.4. Running out of descriptions, my comment was "mega hot". I do remember it was well into the high 30's. On the good days before this heatwave we had achieved 84.0kw on the 14th July and 83.6kw on the 15th.

Whatever the panel people claim, salt should be applied, maybe even a quintal.
 
14 so far at 5pm

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Met Office cloud map showed it to be pretty much clear with VERY light spotty clouds in area but woke up to as I said it raining hard, next doors branches on tree trying to go horizontal and black clouds over half the sky and the sun playing peek-a-boo.

Since I have been using Solcast and Met Office Cloud Map I can't say ive been this surprised before, must have moved over down south super quick overnight, it was really raining last night as well and I thought to myself "hhmmmm this is why it says tomorrow im forecasted for 25kwh and should be a clear sky" lol

I was like "WHAT HAPPENED TO MY NICE POINTY CURVE" lol

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