Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories



Green Building Bible, Fourth Edition
Green Building Bible, fourth edition (both books)
These two books are the perfect starting place to help you get to grips with one of the most vitally important aspects of our society - our homes and living environment.

PLEASE NOTE: A download link for Volume 1 will be sent to you by email and Volume 2 will be sent to you by post as a book.

Buy individually or both books together. Delivery is free!


powered by Surfing Waves




Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




    • CommentAuthorjms452
    • CommentTimeMay 2nd 2021
     
    Hi All,

    We have 4kWp solar from 2012 on FiT that is mostly west facing so I was considering outgoing agile to take advantage of the higher unit rate from 16:00 to 17:00.

    Has anyone successfully cancelled there FiT deemed export and moved this to metered SEG while keeping their FiT generator payment?

    By my reading it looks like you can keep the FiT generator payment and get real export numbers (at a higher rate) under SEG. That said I want to be really sure and not accidentally cancel my FiT generator payment!

    https://octopus.energy/blog/outgoing/

    thanks all
    • CommentAuthorJeff B
    • CommentTimeMay 2nd 2021
     
    I presume you will be on the 50% deemed export rate? If so, this is applicable to you (taken from the Octopus energy blog:

    "50% Deemed was one option under FiT for getting paid for your export. This is often the case where an export meter wasn’t fitted and so it is was assumed that 50% of the solar energy generated would be exported (the other 50% being consumed). This is calculated from the installed potential output of the solar panels at the time of install. You may find you are still better off keeping the Deemed 50% than switching to Outgoing Octopus - for example if in fact you are exporting only 20%, or if the solar panels aren’t optimally oriented to supply the potential output or have deteriorated over several years. As the FiT Export rate is now 5.38pence and our flat rate is 5.5pence then you are better off with Outgoing Octopus if (average over the year) you export more than around 50% of the installed capability".

    Perhaps think carefully about this, especially if your panels are not south facing?
    • CommentAuthorphiledge
    • CommentTimeMay 2nd 2021
     
    I know nothing about the Octopus export rates so I might be missing something, but if you are hoping to make few bob extra, arent you relying on the sun shining regularly between 4 and 5PM? If the sun shines prior to 4PM youll have given up the FIT deemed export payment but may only get lower off peak rates from Octopus???
    • CommentAuthorjms452
    • CommentTimeMay 2nd 2021
     
    Thanks Jeff,

    I'd seen that and suspect it's wrong in degraded panels effecting the choice. FiT deemed export is 50% of your metered generation ( i.e. if I look back over my statements export is always exactly half of generation). So if the PV was were performing badly this wouldn't make any difference in the choice to switch.

    Our Generation was 3729kWh in 2020 and we imported 1300kWh, I don't know what our self use was (another reason it would be nice to have an export meter) but looking at January electricity usage I suspect self use is less than 25%.

    Outgoing agile also appears to pays circa 10p / kWh after 4pm so with our west facing array we'd be double winning from metered time of day export.

    I'm pretty confident it's the right financial decision (if I've understood it correctly) but was hoping someone had already been through this. My main worry is that I inadvertently get opted out of FiT generation as well as FiT export which would be bad! Energy company blogs that don't seem to understand the system don't help this worry.
    •  
      CommentAuthordjh
    • CommentTimeMay 2nd 2021
     
    Don't you need a smart meter for an agile tariff? If so, that should be able to tell you how much you're actually exporting (that's how they measure what to pay you for after all!) and so you can calculate your self-consumption.

    That Octopus blog page seems to indicate that they understand the issues involved, so if I was planning to do it, I think I would write to them first and get them to confirm in writing exactly what you think should happen and what you think shouldn't happen. Then afterwards if things go wrong it should be possible to get redress.
    • CommentAuthorJeff B
    • CommentTimeMay 2nd 2021
     
    Posted By: jms452Thanks Jeff,

    I'd seen that and suspect it's wrong in degraded panels effecting the choice. FiT deemed export is 50% of your metered generation ( i.e. if I look back over my statements export is always exactly half of generation). So if the PV was were performing badly this wouldn't make any difference in the choice to switch.

    Our Generation was 3729kWh in 2020 and we imported 1300kWh, I don't know what our self use was (another reason it would be nice to have an export meter) but looking at January electricity usage I suspect self use is less than 25%.

    Outgoing agile also appears to pays circa 10p / kWh after 4pm so with our west facing array we'd be double winning from metered time of day export.

    I'm pretty confident it's the right financial decision (if I've understood it correctly) but was hoping someone had already been through this. My main worry is that I inadvertently get opted out of FiT generation as well as FiT export which would be bad! Energy company blogs that don't seem to understand the system don't help this worry.


    3729 kWh for a west facing array sounds amazing. I don't know where you are located but on a good year we get 3300 with a south-southeast array and 3000 on average (we are in Pembrokeshire). Like Philedge above, I'm not convinced that it is worth changing for the sake of a few hours worth of decent generation after 4pm but maybe I'm missing something! Might be worth contacting Octopus directly and checking this out.
    • CommentAuthorEd Davies
    • CommentTimeMay 2nd 2021
     
    They're pretty clear that you can still receive the FiT generation payments. From that FAQ page: https://octopus.energy/blog/outgoing/ with my emphasis:

    Would I still get my FiT payments as well as Outgoing Octopus credit?

    Under FiT guidelines, you get paid for being a generator, and paid for whatever you export.

    You won’t be able to receive FiT export payments whilst also being on the Outgoing Octopus tariff. However, you will still be able to receive your generation payments. When you sign up to the Outgoing Octopus, you will be required to opt out of your deemed export payments from your existing FiT supplier (but there’s no requirement to switch your FiT contract to Octopus.)

    For new installations (that is, after the FiT closure date of 1/4/2019) we’ll still require a copy of your Microgeneration Certificate Scheme (MSC) certification in order to get you onto the tariff.
    •  
      CommentAuthordjh
    • CommentTimeMay 2nd 2021
     
    Posted By: Jeff B3729 kWh for a west facing array sounds amazing

    Generation last year was higher than normal. We got 4022 kWh from our slightly-too-horizontal south-facing array, versus 38xx kWh for each of the previous three years (xx = 22,35,84).

    It should be possible to work out what the payments will be given some historical data. I'm sure John has done his sums correctly :)
    • CommentAuthorphiledge
    • CommentTimeMay 2nd 2021
     
    Some interesting generation figures popping up here. @djh, whereabouts are you located? Weve got 3kwp facing SE and 1kwp SW just outside Chester and have had the following results
    2016- 3732
    2017- 3547
    2018- 3740
    2019- 3680
    2020- 3557
    Im surprised a jeff B's figures as Id assumed that being further south generation would have been at least as good as ours!
    •  
      CommentAuthordjh
    • CommentTimeMay 2nd 2021
     
    Hi Phil, I'm in Suffolk so quite a bit closer to John in Cambridge. I think cloud cover is a lot more important than latitude (at least within the UK) but I am quite surprised by Jeff's lower numbers. I suppose he has 4 kWp like the rest of us?

    The difference between your figures and mine does indicate the importance of differences in local weather. For completeness, my full figures are:

    2016 3,963.86
    2017 3,822.45
    2018 3,884.38
    2019 3,835.84
    2020 4,022.27
    • CommentAuthorJeff B
    • CommentTimeMay 2nd 2021
     
    djh/philedge: yes I have a 4 kWp system, however the max it has ever delivered on a typical blue sky day is approx 3.2 kW.

    Here are the averages for the 10 years I have had the system:

    2011...2969
    2012...2902
    2013...3149
    2014...3374
    2015...3275
    2016...2896
    2017...2961
    2018...3022
    2019...3213
    2020...3123

    Average = 3088

    The average per month over this 10 year period:
    Jan...53
    Feb...139
    Mar...267
    Apr...396
    May...450
    Jun...430
    Jul...425
    Aug...360
    Sep...287
    Oct...178
    Nov...78
    Dec...36

    How do these compare with your outputs?
    • CommentAuthorjms452
    • CommentTimeMay 3rd 2021 edited
     
    Posted By: Jeff B3729 kWh for a west facing array sounds amazing


    2.25kWp west and 1.75kWp south both at 45 degrees (too steep) located just south of Cambridge.


    Posted By: Jeff BI'm not convinced that it is worth changing for the sake of a few hours worth of decent generation after 4pm


    Main reason is that I think we export most of it and only get paid for 50% of it. After 4pm generation is the icing on the cake.

    Posted By: djhDon't you need a smart meter for an agile tariff? If so, that should be able to tell you how much you're actually exporting (that's how they measure what to pay you for after all!) and so you can calculate your self-consumption.


    Yep - I was going to do them both in the same process to ensure I get the right smart meter for outgoing PV. Maybe paranoia but I don't fully trust the processes at big organisations to get edge cases right.

    Posted By: Ed DaviesThey're pretty clear that you can still receive the FiT generation payments. From that FAQ page: https://octopus.energy/blog/outgoing/ with my emphasis:


    Thanks Ed.


    Nice to see no significant major in GBF PV arrays!


    Starting the process to join outgoing agile (and get a suitable smart meter) the next step is to get a letter confirming our PV is grid tied from UK power networks!

    https://www.ukpowernetworks.co.uk/electricity/distribution-energy-resources/need-help-with-an-existing-solar-panel
    • CommentAuthorEd Davies
    • CommentTimeMay 3rd 2021
     
    Posted By: jms4522.25kWp west and 1.75kWp south both at 45 degrees (too steep)
    Maybe that's a bit steep for the west-facing panels but for the south facing it might be better to be on the steep side for an agile tariff as, though it'll decrease overall annual production, the higher angle will increase winter and shoulder-season generation which will tend to attract higher prices.
    •  
      CommentAuthornigel
    • CommentTimeMay 3rd 2021
     
    I have signed up to Agile Outgoing, been on it for the last 12 months.

    I did it because I have two solar pv systems, one is FIT and the other isn't. I had to show that both systems were MCSE compliant and also move my FIT to Octopus which was a bit of a hassle.

    I now get paid for all exports based on Agile rates but I still get the FIT payment they said the export element would stop but I think I still get that too.

    If you only have one FIT eligible system I don't think its worth doing.
    • CommentAuthorjms452
    • CommentTimeMay 3rd 2021
     
    Posted By: Ed Davies
    Posted By: jms4522.25kWp west and 1.75kWp south both at 45 degrees (too steep)
    Maybe that's a bit steep for the west-facing panels but for the south facing it might be better to be on the steep side for an agile tariff as, though it'll decrease overall annual production, the higher angle will increase winter and shoulder-season generation which will tend to attract higher prices.


    Indeed - It's lovely seeing kWs of export in the winter and summer evening peak!


    Posted By: nigelI did it because I have two solar pv systems, one is FIT and the other isn't. I had to show that both systems were MCSE compliant and also move my FIT to Octopus which was a bit of a hassle.


    thanks Nigel - nice to hear someone has done it successfully!

    Did you need to get connection confirmation from your network operator?
    Did you leave the FiT generation payment elsewhere and just ask to cancel the FiT deemed export and move this to Octopus?

    I know this will only save me <£100 a year but as we add more renewables to the grid think we need to get past renewables just generating a kWh and move towards rewarding generating a kWh at the time it's needed. In that context so am happy to have a bit of hassle to show support for such a scheme.
    •  
      CommentAuthordjh
    • CommentTimeMay 3rd 2021
     
    Posted By: Jeff Bdjh/philedge: yes I have a 4 kWp system, however the max it has ever delivered on a typical blue sky day is approx 3.2 kW.

    You seem to have much lower output than Phil or myself. I wonder why?

    - I have microinverters, so shouldn't suffer so much from shading problems. Do you have any intermittent shadows on your array?

    - what does PVGIS say about expected output where you live? It's usually quite good.
    • CommentAuthorjms452
    • CommentTimeMay 3rd 2021
     
    Posted By: djhwhat does PVGIS say about expected output where you live? It's usually quite good.


    +1

    We also have very little shading.

    I see lots of installs with chimneys in the middle which even on micro-inverters or carefully stringed will loose a fair chunk of potential output. If they are all on the same string I dread to think...
    • CommentAuthorphiledge
    • CommentTimeMay 3rd 2021
     
    Posted By: djh
    You seem to have much lower output than Phil or myself. I wonder why?


    I think Pembrokeshire should be a fairly good area, certainly as good as us according to the irradiance map, so I guess the lower output is down to panel performance with older panels or not having optimisers??? Im sure the 2011 FIT rates will be ample compensation😁
    • CommentAuthorEd Davies
    • CommentTimeMay 3rd 2021
     
    Posted By: jms452I know this will only save me <£100 a year but as we add more renewables to the grid think we need to get past renewables just generating a kWh and move towards rewarding generating a kWh at the time it's needed. In that context so am happy to have a bit of hassle to show support for such a scheme.
    :clap:
    • CommentAuthorphiledge
    • CommentTimeMay 3rd 2021
     
    Posted By: Jeff Bdjh/philedge: yes I have a 4 kWp system, however the max it has ever delivered on a typical blue sky day is approx 3.2 kW.

    How do these compare with your outputs?


    We see around 3.5kw max on a good day but I think that is a touch lower peak than it could be with having our panels split across 2 roof pitches and a chimney partially shading the 1kw SW facing array.

    The daily averages I have show much the same good months as yours with May being the best followed by June then July and April not too far behind
    •  
      CommentAuthordjh
    • CommentTimeMay 3rd 2021 edited
     
    Our peak power was 3.6 kW but more normally just over 3.5 kW.

    May is typically best with June, July and April fairly close and occasionally better, and August not far behind them.

    In winter there's quite a lot of shading on part of the array from a couple of oak trees.
      Screenshot_2021-05-03 MyEnlighten - Haven Cottage.png
    •  
      CommentAuthornigel
    • CommentTimeMay 3rd 2021 edited
     
    Posted By: jms452Did you need to get connection confirmation from your network operator?
    Did you leave the FiT generation payment elsewhere and just ask to cancel the FiT deemed export and move this to Octopus?


    Yes i had to get the DNO to approve the second system, I have a 3kW and a 4.2kW array but I had to have a max output of 6kW so I have 2 x 3kW inverters.

    My FIT is now with Octopus, you have to transfer it to them if you have agile Outgoing.

    Overall our production over the year almost exactly matches domestic consumption including running an EV.
    I am paying £30 a month for my electricity and I get about £500 a year in FIT so overall running cost is negative.
    • CommentAuthorrevor
    • CommentTimeMay 3rd 2021
     
    Only got my 6Kw up and running on Friday and very pleased with output. During the sunny periods Friday Sat and yesterday it was peaking at 6.5 Kw which was surprising as the panels total 6.03Kwp (Facing SSW 30 deg slope) Battery won't be released for use until completed initialisation by the inverter (2-4 days) so cannot comment yet on how that is doing. I guess the differences output seen by others here will depend on a variety of factors as well as location, panel age, inverter efficiency, quality and size of cables as well as the quality of other components and workmanship. From what I can make out performance can be badly affected by quality of connections, crimping and mixing MC4 manufacturers as well.
    •  
      CommentAuthordjh
    • CommentTimeMay 3rd 2021 edited
     
    Posted By: nigelMy FIT is now with Octopus, you have to transfer it to them if you have agile Outgoing.

    That doesn't seem to be the case based on what the previously quoted page says?
    From https://octopus.energy/blog/outgoing/ :

    "When you sign up to the Outgoing Octopus, you will be required to opt out of your deemed export payments from your existing FiT supplier (but there’s no requirement to switch your FiT contract to Octopus.)"
    •  
      CommentAuthornigel
    • CommentTimeMay 3rd 2021
     
    Posted By: djh
    Posted By: nigelMy FIT is now with Octopus, you have to transfer it to them if you have agile Outgoing.

    That doesn't seem to be the case based on what the previously quoted page says?
    From https://octopus.energy/blog/outgoing/ :

    "When you sign up to the Outgoing Octopus, you will be required to opt out of your deemed export payments from your existing FiT supplier (but there’s no requirement to switch your FiT contract to Octopus.)"


    Well if you don't have to move your FIT, don't, because it was a major pita.
    • CommentAuthorJeff B
    • CommentTimeMay 3rd 2021
     
    Posted By: djh
    Posted By: Jeff Bdjh/philedge: yes I have a 4 kWp system, however the max it has ever delivered on a typical blue sky day is approx 3.2 kW.

    You seem to have much lower output than Phil or myself. I wonder why?

    - I have microinverters, so shouldn't suffer so much from shading problems. Do you have any intermittent shadows on your array?

    - what does PVGIS say about expected output where you live? It's usually quite good.


    I've had a look on the PVGIS website and put in some figures. I know the roof slope is 49 degrees but how do I determine the azimuth? If the panels are facing south-east does that equate to an azimuth of 45 degrees?
    • CommentAuthorjms452
    • CommentTimeMay 3rd 2021
     
    Posted By: djhYou seem to have much lower output than Phil or myself. I wonder why?


    Posted By: Jeff Bthe roof slope is 49 degrees


    Mystery solved - Jeff you'll do much better early in the day with that!

    Posted By: Jeff Bhow do I determine the azimuth? If the panels are facing south-east does that equate to an azimuth of 45 degrees?


    I think 315 degrees
  1.  
    Posted By: Jeff BI know the roof slope is 49 degrees but how do I determine the azimuth?

    If this is a query about the azimuth when using PVGIS then when you 'visualize the results' to the right of the bar chart there is a (sort of) compass rose which if you hover the cursor on the perimeter and move it around the perimeter this will show you the azimuth that PVGIS wants relative to the compass point. (south is 0, west of S is +degrees and east of S is -degrees )
    Also shown on the rose is the sun height for June and December along with the presumed horizon height for your location
    • CommentAuthorEd Davies
    • CommentTimeMay 3rd 2021
     
    Posted By: Jeff Bbut how do I determine the azimuth? If the panels are facing south-east does that equate to an azimuth of 45 degrees?
    Amost, -45° is south east, 45° would be south west. From the Users Manual at:

    https://ec.europa.eu/jrc/en/PVGIS/docs/usermanual

    The azimuth, or orientation, is the angle of the PV modules relative to the direction due South. - 90° is East, 0° is South and 90° is West.
    315 would be equivalent but the web site wants a number in the range -180 to 180.
    • CommentAuthorJeff B
    • CommentTimeMay 3rd 2021
     
    Thanks for the many comments and the azimuth figure. I have run the PVGIS routine using a roof slope figure of 49 degrees and azimuth angle of -45 degrees and it calculates I should be achieving 3792 kWh p.a. The average figure we have achieved in 10 years is 3099 (range: 2896 to 3374). Out of interest I have calculated the difference in outputs per month between my actual average data and PVGIS calculated data - see attached spreadsheet.

    The largest differences in percentage terms are for the months of Jan, Feb, Mar, Oct, Nov and Dec. I think the explanation for this is that the sun is quite low on the horizon during those months and my neighbour's trees effectively block the sunlight even though they are bare at those times. I do have micro-inverters so if I didn't I think the figures would be much worse. From April to September the sun is higher in the sky and for most of the day is well above the trees. It is noticeable though that after about 1pm the PV output starts to drop significantly as the sun moves around to the SW and W.

    We have had thoughts about moving some of the PV panels from the SE facing roof and putting them on the SW facing roof. There would only be room for 6 panels on the latter though, leaving 15 on the main roof so may not be worth the hassle/expense. Also not sure if this may be an issue with the FIT i.e. altering the system layout?

    P.S. Apologies to jms452 for hijacking the thread.
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press