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Renewable Energy: did your PV generate less in 2012?

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1 to 29 of 29

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  1.  
    I'd be interested to know if people have compared their 2011 and 2012 power generated - it felt like the sun hardly appeared at all in Manchester last year and it's putting some people off considering solar pv installations ... anyone got any relevant generation figures?
    thanks
    Sarah
  2.  
    try http://pvoutput.org/help.html#overview see what system in your local area have been up to.
    • CommentAuthorBeau
    • CommentTimeJan 7th 2013 edited
     
    Truly dreadful here this year.
    I can give accurate figures in a couple of months time as that's when 2 years is up on one of the systems here but it does not look good and it's not if we had a decent year in the south west in 2011. Gut feeling is we need to be prepared for many more years like this one and be grateful if we have a long term average year. We did see the sun for a few hours on New years day but not been seen since. I looked at some local weather data and it has rained on average 3 out of 4 days here since May this does not prove it's been cloudy but it's a good indication of what it's been like.

    Beau from a miserable dank and cloudy Dartmoor.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 7th 2013
     
    Posted By: BeauBeau from a miserable dank and cloudy Dartmoor.
    Sun is out here, from Cornwall :surfing::boogie::shades:
    • CommentAuthorbillt
    • CommentTimeJan 7th 2013
     
    Here in Shropshire it's been a bit low, but not disastrously so. Average from July- December is 1.3% lower than the previous year. (My system started in mid June 2011.)

    For 2012 the output is 4.6% above the PVGIS classic estimate but 6% below the PVGIS climate-SAF estimate. For us production hasn't been much lower than expected.
    • CommentAuthorBeau
    • CommentTimeJan 7th 2013 edited
     
    Don,t rub it in ST unless you fancy a house swap so me and the wife could dry out for a few days :bigsmile:
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 7th 2013
     
    I am meant to be going to Plymouth this week, I shall pack my mac.
    Clouded over now :devil:
  8.  
    2011 generation 2828kWh (106% of PVGIS climate-SAF with 14% system losses)
    2012 generation 3141kWh (118% of PVGIS climate-SAF with 14% system losses)

    N.B. We were the corner of the UK where it was very wet while the rest was building up to a drought, then dry when if started raining everywhere else (I've had a rain gauge since the start of 2008, in 2012 March to October, inclusive, all had below average rainfall).
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 7th 2013
     
    Was that compared to the long term average or the 2008 to 2012 average?
    • CommentAuthorJeff B
    • CommentTimeJan 7th 2013 edited
     
    My "PV year" runs from April to March, as my system was installed on April 1st 2011 (yes, I know, no jokes please!), so I don't have a whole year's worth of data for the current year. However comparing the 9 months from April to December for each year I have:

    Apr 2011to Dec 2011 = 2530 kWh
    Apr 2012 to Dec 2012 = 2437 kWh

    So, surprisingly, little difference actually (down about 100 kWh).

    If I assume that the coming Jan, Feb and March figures are the same as last year, then the totals for the 2 years would be:

    Apr 2011 to Mar 2012 = 2969 kWh
    Apr 2012 to Mar 2013 = 2876 kWh

    So again about 100 kWh down.

    Now, if anyone had asked me this question, the "off the top of my head answer" without checking the figures would have been that we were significantly down on last year, not because of the rain so much (we've not had it so bad as some parts) but just the number of overcast days. When the sun appears lately it is an immediate talking point. I wouldn't be surprised to see a resurgence of rickets amongst children down in these parts (west Pembs)!

    I should add that ours is a 3.9 kWp system.
  11.  
    Three (and a bit) years of Tyneside PV, by month and year, here: http://www.ccandc.org/cgi-bin/pv?START=end-1d&END=now

    2010 generation 1243kWh
    2011 generation 1326kWh
    2012 generation 1234kWh

    2012 went wrong for me just after I boasted on GBF about having had the best Dec2011/Jan/Feb/March2012 in three years: I then got the worst April-July which should be the bulk of the years' generation :-/
  12.  
    4020 kWh gen 12/11-12/12, SE facing array , 3.68kWp DNC , SE UK
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 7th 2013
     
    Worth remembering that most panels don't produce any more power when the solar power is over somewhere between 800 and 1000 W/m^2. As most energy is produced between the spring and autumn equinoxes, even an overcast day can still produce a near enough maximum power, the losses being at the beginning and end of the days, which hardly produce anythign anyway. You also benefit from less shadows (if they are a problem on your roof) on overcast days. Shadowing causes a high resistance in a panel, turning it into a heater. To overcome this your inverter (if fitted with MPPT) takes less power from the system to compensate (and preserve the longevity of your module).
    So we may have had 'less sunshine' but mean figures are pretty stable.
    Probably a different story with solar thermal, anyone got figures for that?
    • CommentAuthorBeau
    • CommentTimeJan 7th 2013
     
    We have 2 systems here one is at 15 degrees due south and the other is 36 degrees due south. I have noticed how the flatter system performs proportionally much better on cloudy overcast days than the optimal 36 degree system regardless of time of year.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 7th 2013 edited
     
    Yes it will as it takes advantage of scattered light, but does it require more cleaning, actually, do you ever clean them?
    • CommentAuthorBeau
    • CommentTimeJan 7th 2013 edited
     
    Nope never felt the need as well washed by the gentle hand of mother nature O and the bl@@dy rain :bigsmile:
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 7th 2013
     
    You might find the 15° one may benefit, the 36° one not so much, though it is amazing how much dusts there is in our rain, was only a few weeks back we had some Sahara sand hitting us.
  18.  
    In 2010 I made 7048 kWh, in 2012 it is down to 6821 kWh; not a significant drop BUT this year for the first time we used less electricity than we made - YIPEE! I might try cleaning my 15 deg panels this year as I often get 6-10 weeks without rain, albeit much of that time I am also getting over 800 W/m2 !!:cool:
    • CommentAuthorCWatters
    • CommentTimeJan 8th 2013
     
    Wasn't it the second wettest year on record? With all that extra cloud, not surprised PV output is down.
    • CommentAuthorsarahhughes
    • CommentTimeJan 8th 2013 edited
     
    Thanks very much everyone.
    • CommentAuthorskyewright
    • CommentTimeJan 8th 2013 edited
     
    Posted By: SteamyTeaWas that compared to the long term average or the 2008 to 2012 average?

    My own rainfall data only goes back to 2008, so it's a highly localised 2008 to 2012 average I'm commenting on.

    The Met Office used to have nice charts for this sort of thing, but I can't find them on the new style website. The pages that seem to be the equivalent of what I'm after don't show data after 2010, but I could easily be missing something obvious.

    Assecondary evidence that the effect applied to NW Scotland more generally, you might be interested to know that the water authority had to tanker in water to some places...
    • CommentAuthorbillt
    • CommentTimeJan 8th 2013
     
    My solar thermal output was 4.56Mwhr last year and 5MWhr in 2011, 8.5% down. 2.06MWhr and 2.16MWhr for the second half year, 4.5% down.

    Still, this year's going to be nice and sunny to compensate!
    • CommentAuthorSeret
    • CommentTimeJan 9th 2013
     
    I wasn't generating in 2011, but my output for 2012 was 97% of PVGIS climate-SAF.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 9th 2013
     
    PVGIS tends to be a bit cautious, about 5% less on the kWh, not sure now they have updated the model data.
    • CommentAuthorMikel
    • CommentTimeJan 9th 2013
     
    My output for the year ending 4th October 2012 was 3559 kWh (3.84kw array). PVGIS-Classic estimated 3620 kWh. So that works out at 98% of PVGIS estimate.

    For Camborne the average annual sun hours are 1638 hrs for the last 31 years and 1643 annual hours average since 2000. The sun hours for the year to October 2012 are 1385 hrs (data come from Met Office web site). So it appears we have had about 85% of the average annual sunshine in this neck of the woods.

    Not surprising that the figures are on the low side.
    •  
      CommentAuthorSteamyTea
    • CommentTimeJan 9th 2013
     
    Posted By: MikelFor Camborne the average annual sun hours are
    Is that just hours of sunshine or clear sky?
    I can't seem to track it down on the Met Office website today.
    • CommentAuthorMikel
    • CommentTimeJan 9th 2013
     
    • CommentAuthorMikel
    • CommentTimeJan 11th 2013
     
    The Met Office data for December for Camborne is now up. 37.4 sun hours recorded (provisional figures). This compares with the long term (30yr) average for December of 58 sun hours.

    Down here, most of those sun hours were in the first half of the month. Our PV production for December was 85% of the PVGIS-Classic estimate.
    • CommentAuthorGavin_A
    • CommentTimeJan 11th 2013
     
    Posted By: SteamyTeaPVGIS tends to be a bit cautious, about 5% less on the kWh, not sure now they have updated the model data.

    obviously depending on what losses you use - the 14% standard figure is very conservative. We mostly use somewhere between 7-10% losses for unshaded systems depending on fairly precise inverter & cable loss figures, and it's proving remarkably accurate once you factor in solar input levels (approximated from the local met office stations sunshine hours stats).

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