Syd Posted June 4, 2012 Share Posted June 4, 2012 Well not really a puzzle more something that I have been playing about with in my mind for a couple of weeks. Have come to my own conclusions on this but expect them to be incorrect and so I turn to the experts for help. I have a roof full of solar panels that over the last 13 weeks have averaged out producing approx 15 units of electricity per day. I am paid the higer rate for the electricity produced and if I use the power generated then I gain again up to around 60p per unit. (I think) What I have been toying with is useing this production of power to charge batteries to run through an inverter to run the washing machine and maybe the drier too. Even the central heating of the Combi boiler when the washer/drier are not in use The washing machine and the drier are both rated at 1200w so I realise that they cannot both be run at the same time. What I am asking is what is the most economical way of doing this ie How many batteries would I need, what chargers will I need and which inverter would be the best one to use and/or is this just another one of my stupid idea's I do know that you cannot get perpetual motion but I feel that the FIT payment just might make it work if I could work it all out HELP PLEASE Link to comment Share on other sites More sharing options...
BGD Posted June 5, 2012 Share Posted June 5, 2012 Syd - here in Spain there are a LOT of country properties out in the "campo" with no mains electricity. Many of them seem to exist on solar panels, batteries (BIG batteries), and a generator for backup (which seems to kick in automatically if/when required). Sometimes a windmill too. I know nowt about the technicalities, except that even here with wall to wall sunshine most of the year, they still need a LOT of solar panel area, and a lot of batteries in a bank too....then I assume a meaty inverter to get the DC voltage (I think Spanish systems often work on 24 volt DC) to AC mains; and of course a bucketload of fancy control system wires/black boxes. There are a lot of companies over here who specialise in designing/installing such systems to fit your requirements...it seems quite an established market in Spain. But damned expensive by the look of it. Link to comment Share on other sites More sharing options...
Guest Tracker Posted June 5, 2012 Share Posted June 5, 2012 It's not a stupid idea Syd but it would be very expensive to implement and the returns would be dubious with a very long pay back period - if ever. When we had our panels fitted I spoke at length to our supplier about this and he made some enquiries and we did some calculations before deciding against. A ground source heat pump would be more cost effective for heating and a better allocation of funds was our combined view. The non technical outcome was that there are not enough hours of sunshine and I don't have space for enough panels to make it viable without a backup generator and as we are connected to the mains it is better to just accept with grateful thanks the generous government subsidy for as long as it lasts! In the first full 12 months our panels paid me £1953 in FIT payments and I also reckon to have saved a bit on my electric bill - very hard to assess but it looks like about £12 a month so far and on that basis I have a payback time of less than 6 years at today's prices. If (as) electricity goes up in price and if the FIT continues in line with inflation that period will reduce. So far with a return of over 15% I am chuffed with my investment and another way to see it is 'free' home energy as my total oil and electricity bills are much less that the income generated. I was effectively offered 'free' home energy for 25 years for a one off payment of £13K - so I took it - and even with loss of interest at 3% on that capital I am still well in pocket and that will do for me! Link to comment Share on other sites More sharing options...
josie gibblebucket Posted June 5, 2012 Share Posted June 5, 2012 All I can say is you two must have had better weather than me then. We've got 14 panels, fitted last November (sadly we missed the really unusually sunny October) but we are not generating at anything like the rate that you two seem to be. Not helped by the wet overcast spring weather either. I doubt we will even make the SAPS figures that were bandied about this year :-( Link to comment Share on other sites More sharing options...
colin Posted June 5, 2012 Share Posted June 5, 2012 From what I've read, the art is to use apliances when the panels are suppling enough to run them, or at least to offset the costs. Having a combi boiler means you are missing one way which is using an imersion heater. http://www.reuk.co.uk/Water-Heating-with-Surplus-Solar-PV.htm Link to comment Share on other sites More sharing options...
Guest Tracker Posted June 5, 2012 Share Posted June 5, 2012 Starting on zero on 6th May 2011 we generated 4354 units up to and including 5th May 2012. Our system was a tad more expensive because we opted for better panels and the most efficient inverter - within sensible cost - that we could get. It seems to have paid off! The unit rate up to 31.3.2012 was 43.30p plus the extra export rate of 3.1p per unit on 50% of the output which averages out at 44.85p per unit overall. This year it is 45.80 for generating and 3.2 for export which averages out at 47.40 per unit overall and if we do the same again this year we will earn £2064 - plus whatever we save on electric by using our own power when the system is generating. We have our hot water heated by oil from 6 pm to 8 am - not that it is on much overnight - and via time switch by electric from 8 am to 6 pm which, in conjunction with everything else we use during the day means we use less units of NPower's finest and more of our own. The beauty of it is that if I use my own generated power I not only get paid 47.4 p per unit but I don't pay NPower 9.33 per unit so it saves me 56.73 per unit. Good innit!!! Link to comment Share on other sites More sharing options...
Syd Posted June 5, 2012 Author Share Posted June 5, 2012 When having our panels fitted I did consult with Tracker once and we has 14 panels fitted giving us a 2.8 set up. At 13 weeks we generated 921 units ie 28th Feb to 1st june and as Tracker said picking the best available certainly pays off We are at Sunderland in the North East so we have a lot less sun than the southerners plus there has been a lot of rainy days Link to comment Share on other sites More sharing options...
Guest Tracker Posted June 5, 2012 Share Posted June 5, 2012 That's pretty good Syd and if you compared your system with mine annualised and pro rata your 14 to my 16 panels it compares very well at around 4210 units per annum. As you have the sunniest part of the year - in theory - yet to comes your's may well surpass my annual figure by the time you get to Feb 2013? Link to comment Share on other sites More sharing options...
Syd Posted June 6, 2012 Author Share Posted June 6, 2012 I am very pleased with the output as our normal electricity bill is around £260 per quarter and I calculate we have generated around £386 in FIT. Link to comment Share on other sites More sharing options...
josie gibblebucket Posted June 6, 2012 Share Posted June 6, 2012 Syd - 2012-06-05 10:21 PM When having our panels fitted I did consult with Tracker once and we has 14 panels fitted giving us a 2.8 set up. At 13 weeks we generated 921 units ie 28th Feb to 1st june and as Tracker said picking the best available certainly pays off We are at Sunderland in the North East so we have a lot less sun than the southerners plus there has been a lot of rainy days We have 14 panels giving us a 3.5 set up. 250watts each panel surely? But here 21st Feb to 21st May, just 520 units. We are south facing and normally get loads of sun, but as I said its been so miserable, cloudy and wet for all of April (only 1 day without rain) and 3 weeks of May that we're not doing very well with ours, have to say I am quite disappointed :-S Link to comment Share on other sites More sharing options...
Guest Tracker Posted June 6, 2012 Share Posted June 6, 2012 josie gibblebucket - 2012-06-06 4:46 PM We have 14 panels giving us a 3.5 set up. 250watts each panel surely? But here 21st Feb to 21st May, just 520 units. We are south facing and normally get loads of sun, but as I said its been so miserable, cloudy and wet for all of April (only 1 day without rain) and 3 weeks of May that we're not doing very well with ours, have to say I am quite disappointed :-S Don't give up just yet Nicola as it has hardly been the most sunny or brightest of spring times this year and by the time another 6 months has passed I would expect you to be much happier. Give 'em a chance!! Link to comment Share on other sites More sharing options...
Syd Posted June 7, 2012 Author Share Posted June 7, 2012 josie gibblebucket - 2012-06-06 4:46 PM Syd - 2012-06-05 10:21 PM When having our panels fitted I did consult with Tracker once and we has 14 panels fitted giving us a 2.8 set up. At 13 weeks we generated 921 units ie 28th Feb to 1st june and as Tracker said picking the best available certainly pays off We are at Sunderland in the North East so we have a lot less sun than the southerners plus there has been a lot of rainy days We have 14 panels giving us a 3.5 set up. 250watts each panel surely? But here 21st Feb to 21st May, just 520 units. We are south facing and normally get loads of sun, but as I said its been so miserable, cloudy and wet for all of April (only 1 day without rain) and 3 weeks of May that we're not doing very well with ours, have to say I am quite disappointed :-S Hi Josie As Tracker will tell you why in greater detail than I can that you HAVE to get a good quality inverter otherwise you will loose quiet a bit of your panels production. Just read my meter and we have produced 950.11 units, very dull all day today Link to comment Share on other sites More sharing options...
josie gibblebucket Posted June 7, 2012 Share Posted June 7, 2012 I was minded to pay more and buy an Aurora inverter, but was persuaded that a SunnyBoy would be more reliable, but I did get what I believed to be decent panels. :-| Going on your figures from 1st June, you have generated 29 units in 6 days then? I think we have done 143 in 17days, so its not a complete disaster. Its not that they are not working, rather that we have had such dreadful weather >:-( Link to comment Share on other sites More sharing options...
Syd Posted June 29, 2012 Author Share Posted June 29, 2012 Today telephoned in our feed in tarrif reading 1120 units since 28th Feb, I was told that this will entitle us to a FIT payment of £507.50 I was also told that we have produced 144%, this aparently means that our panels have produced 44% more than the max production that our FIT company (Gas Board) thought our panels would produce during that time. I am very pleased with this payment as our electricity bill this past quarter was £126.00. Link to comment Share on other sites More sharing options...
Guest Tracker Posted June 29, 2012 Share Posted June 29, 2012 In the first full year our solar panel income was about £500 greater than our combined oil and electricity bills. Luvly jubbly!! Link to comment Share on other sites More sharing options...
Syd Posted June 29, 2012 Author Share Posted June 29, 2012 Hi Tracker I was hoping that you would come back with some comparison figures so I could see how our 2.8kw system compared with your 4kw system, easier said than done I know but I was hoping. Our friend who has a 4kw system on a directly south facing roof got less from his system than we did from ours, cannot understand it really Link to comment Share on other sites More sharing options...
Guest Tracker Posted June 29, 2012 Share Posted June 29, 2012 Hi Syd, Much depends on variables which, as you know - er - tend to vary!! Roof pitch angle and direction, trees, power poles or buildings nearby that shield the passing sun, make and type of panel, make and type of inverter. On that basis any comparison is only ever going to be approximate. My neighbour and I had ours at the same time, same company, same spec - almost! He opted for a cheaper inverter than I did, his roof is slightly different in pitch and direction and he has a tall pine tree in his garden. Result - about 10% less than I get - but we don't know which factor plays which part in this. Link to comment Share on other sites More sharing options...
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