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 The Green Pages


Here locals can send in their experiences of trying to be more environmentally friendly. I will start it off with Website HQ's new Solar PhotoVoltaic Microgeneration system. The Ed.




Web HQ 4 Kwp Solar Photovoltaic Microgeneration System.




We first started looking at a Solar PhotoVoltaic installation after reading about a firm in the Midlands who were installing free systems where the householder would receive all the generated electricity for free. They would install and maintain the system completely free and leave it there for 25years. This got me thinking, how could they afford to do this and why can't we have this on the Island?


Once I started to investigate, I discovered that the Government had introduced in April 2010 something called a Feed In Tariff. Basically this is a payment of 41.3p for every unit of electricity that is generated whether used or not by the householder, plus an extra 3p per unit for every unit that is exported to the grid. This compares to about 12p per unit that we currently pay for our electricity. There is also a saving from the electricity you don't have to buy.


It became clear the midlands firm was claiming the tariff to pay for the system, so I wondered how much a system would cost and exactly how much cash would it generate.


After looking at various internet sites including the Energy Savings Trust, a 4Kwp system would cost around £16,000, but the Feed In Tariff would provide an inflation proof tax free income of between 8 and 10% guaranteed for 25 years. This means a payback period of about 10 years, then 15 further years of guaranteed income. The figures for the Feed In Tariff are set by the Government, but crucially from my point of view, are paid by your chosen electricity supplier. Personally I would not trust the tariff system to last 25 years if it were paid by HM Govt., as any Govt. expenditure can be cut at any time, as has been proved recently.



Getting Quotes


The problem of getting quotes for the Solar PV Array is made easier in some respects by some of the rules regarding the Feed In Tariff. The system must be installed by a MCS registered  Solar PV installer who has passed various courses specifically on Solar PV systems. The equipment used also has to be MCS certified. One benefit of this is that VAT is charged at 5% instead of the normal rate. The other consequence is that there were only 4 MCS registered installers on the Island when we started looking. We spoke to all 4 Island installers, some seemed very good, but expensive, others quoted unrealistic systems from a technical point of view, ie. quoting for more panels than could physically fit on our roof. We also found that Tesco were doing fixed price installations through an installation company, these seemed very competitive, but ultimately after nearly 2 months they finally quoted for an expensive very small system which was not at all what we wanted.

Meanwhile we contacted various mainland installers, which had recommendations from various forums on the internet. One of which, Solar Focus, sent over a surveyor from Kent, who bothered to listen to what we actually wanted and quoted us a reasonable price for the whole job using Sharp Monocrystalline Panels and special SMA inverter that could cope with two uneven arrays at 90 degrees to each other, thus allowing us to get to the 4KwP system we wanted. We liked the Sharp panels because they are well known and liked, plus they are actually made in the UK!!, Wrexham to be precise. They also quoted us about 4 weeks lead time for installation, so early August we paid our deposit and true to their word they started installing on the 31st.




Day 1


8.45 - 11.45am - Scaffolding Erected



As arranged by the installation firm, local scaffolding firm, Dee's, erect a platform for the installtion team to safely work on the roof.


6.15pm - Installers, Solar Focus, Deliver Solar Panels and Inverter



The 2 man installation team arrive on the island and immediately drop off the very expensive Solar PV Panels and Inverter rather than leaving them in their van overnight at their Hotel. They also double check the roof dimensions ready to start the installation early next morning.


Day 2 - Installation Day



7.45am - Installers Joe and Dave arrive and start to install the panel fixing brackets.



Fixing the brackets to the roof trusses is very time consuming and takes nearly all day. At first I thought the brackets would disturb the way the tiles lay together, but after hours of grinding bits off brackets and tiles, then applying lead flashing to keep it all watertight, I needn't of worried as the finished result shows.



Horizontal Stainless Steel bars are then attached to the brackets before vertical bars to which the panels are fitted.





5.15pm - The first panel goes up, ensuring the panels are below the height of the ridgetiles, to keep the planning dept. happy.


Day 3


After early morning discussions with Joe, Dave and Adam, the Surveyor, its decided to split the panels; 15 on the main SE facing roof and 7 on the smaller SW facing roof as this should produce the best output matched to the SMA 4000TL inverter, which was chosen as it is suitable for unevenly split panel arrays.


The last panel goes in, just the wiring to go!!



The DC Power cables from the two strings are threaded through the roof sections and the porch to the garage where the inverter is to be installed.


The Inverter, which is far bigger and heavier than I expected goes in.


5.07pm - Its all a bit of a race against time as the sun is fast dissappearing behind the cliff and ideally the fitters need a fair amount of light falling on the panels for them to switch the inverter on so they can commission and test the system.


6.15pm - The sun is well behind the cliff, but the panels are still producing voltage, but it looks like Joe and Dave will be staying on the Island another night, so they can finish off and commission the system in the morning.


7.45pm!! - The system is fully installed, but although it registers the string voltage, there is not enough current to power up the inverter as its getting dark. We'll have to wait till tomorrow for the commissioning.




Day 4



It Works!!!, its cloudy, but the system is producing 1.5Kw, we have earned 40p Woo Hoo!!!, but its only been on about half an hour and its only 9.30am.


10.30am - Joe and Dave have tidied up and are off to catch the ferry, going to Cornwall for the next job!!! - We can't believe how long and hard they work, very impressed!!



Alaster at the Solar Focus office registers our system on the MCS website and they email us our MCS Certificate which we then send to EDF, our electricity supplier, with their Feed In Tariff application form. Once accepted EDF will then send us a Cheque every 3 months based on our Total Generation Meter readings.


Alaster also arranges for the scaffolding to be removed, as until this is done there will be some shadowing of the panels reducing their efficiency.



8.00pm - The sun has gone down and we watch [Sad I know] the Watts generated gradually drop to zero. The first day has been hazy sun/ light cloud all day and we have generated 17KwH which has earned us £7.90, not bad considering it was not switched on til 9.30, the scaffolding is still shading a bit and it was a bit hazy. The system peaked at 3.012Kw at 12.40 suggesting on a good day we should be nearing the 4Kw maximum the system is capable of.


The graph shows the 1st day's output starting at 9.30. The wireless data from the inverter is picked up by my laptop's Bluetooth receiver and displayed using Sunny Explorer software. 




Solar Focus also supplied a display device called a Sunny Beam Bluetooth, which also picks up the data from the inverter and displays it wirelessly in the house so you can keep an eye on what is being generated. This is also solar powered. The above display shows a graph of the days output and the actual output at that instant [822W], below that is the output for that day [6.67Kwh] and the systems total output since commissioning [49.44Kwh], Photo taken on 4th day of generation, a gloomy day at about 2.00pm.



After Installation


3/9/10 - For Investment Comparison the FTSE = 5428.1 Today


5/9/2010 - 10.45am - 32.34Kwh and £14.55 so far since 3/9, currently raining but still generating 473W and 1.08Kwh today so far.


6/9/2010 - 12.00 Dee's arrive to remove the scaffolding. Hopefully the sun will come out and we can get an idea of the maximum output with no shading from the scaffolding, unfortunately it starts to rain.


 The finished installation.


7/9/2010 - EDF Confirm receipt of our Feed In Tariff application by post.

7.30pm - 14.06Kwh today making a total of 65.41Kwh [About £29] over 5 days since commissioning, we would have earned about £5 in interest if we left the money in our Building Society. Still not had a proper sunny day yet, hazy sunny intervals today.


10/9/2010 - Its been a week since it was turned on and we have generated 94.9 Kwh of electricity which is an income of £40.61 plus some savings on our electricity bill, so about £45.00 in total. Not bad for a week considering it was not terribly sunny. If we had left the money in the building society it would have earned us about £7.55 in interest at 2.5%. The system also reports we have avoided producing 66.43Kg of CO2 - That sounds like quite a weight to me!!! Out of the 94.9Kwh of generated electricity we have probably only used about a third, so the rest is exported to the grid and used locally in the village.


30/9/2010 - Its been 28 days since the system was switched on and we have generated 330KWh of electricity with an income of £141.24.



The graph shows the daily output in KWh for each day of the month, the best day was the 25th with 19.62KWh, the worst being the 14th with 2.15KWh. The average generation for September was 11.78KWh per day. September is probably about average for solar irradiation over the course of the year, so if we generate at our September daily average, we should generate about 4300KWh [About £1840] over a year which is a return of 11.7% on our investment plus a saving on our electricity bill. During September we have used an average of 8.2KWh a day, but according to our meter we have bought an average of 5.2KWh a day, so we have saved buying about 3KWh per day, which equates to about £10 a month saving.



31/10/2010 - October has been very sunny and we have generated 293Kwh of electricity, which is an income for the month of £125.40, making a total since switch on of 623kWh and an income of £266.64.



The graph above shows the daily generation for each day of the month. The expected total for the month was 241.5Kwh [Latest PVGIS Estimate] so we are way above our predicted figures for the first 2 months at 10.56 Kwh per day. We have imported 197Kwh of electricty during the month at a cost of £22.28, but we have used 290Kwh which would normally have been £32.80, so an extra saving of £10.52 for the month [All figures are based on 11.31p per unit [Inc 5% VAT] excluding EDF's standing charge].

We are using about a third of what we generate, the rest is exported to the grid and used locally, which is a benefit for the environment as there are much lower transmission losses as the power does not have to come miles from the most local power station, in Cowes as far as I know.


30/11/2010 - November has been a bit dull, very wet, with snow towards the end of the month but we have still generated 142kWh of electricity which is an income of £61.06 for the month, making a total of 765kWh and £328.95 income since installation.



The graph above shows the daily generation for each day of the month. The expected total for the month was 152kWh, so we have generated slightly lower than the latest PVGIS prediction.


23/12/2010 - At long last, EDF have sent back the 25 year Contract to be signed and a request for a Generation Meter reading. We have Generated 837.7kWh since 3/9/10 which should mean a payment from EDF of £358.53 will be paid wheras we have used 836.4kWh but only paid them £94.59. So in what will probably be the 2nd worst quarter of the year we have produced almost exactly what we have used, but have made a profit of £263.94 due to the Feed In Tarrif.


29/12/2010 - The next quarter to March will almost certainly be the worst period of the year for generation, with a prediction of 577kWh from 21/12/10 to 21/3/11 as against 830kWh from 3/9/10 to 21/12/10. [Using the latest Autumn 2010 Climate-SAF PVGIS Website Estimator]. The new estimate for the whole year has increased to 4270kWh, which is remarkably similar to my guestimate of 4300kWh based purely on September's total being an average month!! Out of interest the UKGovt. Standard figure for our system which has to be given on a quotation was 3066.62kWh. We should be well above that figure as we have already done over 27% of that figure during the Autumn/Winter!! and 2/3 of the years total is generated during the April - August period.


31/12/2010 - Despite no generation at all on several days due to the panels covered in a thick layer of snow, we have still managed to generate 99.1kWh during December which is just ahead of the PVGIS estimate of 97.7kWh.


The graphs for Oct, Nov and Dec are all to scale and show anoticeable reduction in the peak sunny day generation due to much shorter daylight hours and the sun being at a much lower angle in the sky.

During the month we have imported 303kWh [£34.24] according to our electricity meter, but have used 350kWh [£39.55], which means we have used approx. half of our generation saving us a paultry £5.31 of our bill, but we will receive a Feed In/Export Tariff of £43.40. So even in the worst month of the year for sun we have made/saved £48.71 and still well above our import cost of £34.24.

The year end total generation stands at 864.1kWh which equates to an income of £378.47 plus an electricity bill saving of approx £33 and 604.32Kg less CO2 in the atmosphere for 120 days since 3/9/2010. During that period we have lost about £130 in interest at 2.5%, which we would have received if we had not purchased the system, so the actual return is approx. £280 for the 4 months.


1/1/11 -  See our new Solar PV Statistics Page for full details of generation, expected generation and income. 


31/1/2011 - As expected January was very grey, but the system generated 122kWh, just above the 121.1kWh PVGIS prediction, Click  Solar PV Statisticspage for full data etc.


Adam from SolarFocus came down to the village during the month and they will be installing two more systems during February.


25/2/2011 - SolarFocus have installed two more 4kWp systems in the village this week despite it raining for most of it. Joe now has a 3 man team so they managed to finish both systems despite the rain. It will be interesting to compare the output of each system as they all have about the same capacity, but on very different roofs.


26/2/2011 -  The new Feed In Tariff from 1st April 2011 has been announced, as expected it has been raised by the Retail Price Index for 2010 which was 4.8%. The new rate is going up from 41.3p to 43.3p per unit generated and to 3.1p from 3.0p for exported units for Roof Mounted systems under 4kWp installed before April 2012. This should increase our income and shorten the perceived break even period even further. Reports in the press of the Fit being reduced or even withdrawn refer to the New Government reviewing industrial scale installations greater than 50kWp as these threaten to swamp out the small household sized generator and take all the available FIT allowance. Apparently there are 6 huge sites being applied for on the Island alone!! Obviously big business can see a fast buck to be made, even though these huge installations only get about 30p per unit.


28/2/2011 - End of month report - February was dismal, only 138.7kWh generated in the month, well below the expected 186.6kWh.



The only encouraging thing was the peak output when the sun actually came out reached 3.8kw albeit only for a few seconds. 


1/3/2011 - Looks like EDF are getting their act together at last, today we received an email request for a quarterly generation meter reading and also the payment for the previous quarter arrived in our bank. 


24/3/2011 - Having sucessfully installed 3 complete Solar PV systems in the village, Solar Focus have kindly offered to sponsor this page. If you are interested in a Solar PV System, give Adam Smith a ring on 01732 424106.


31/3/2011 - March was very sunny and we generated 411.7kWh, well above the predicted 353kWh.


We also managed to use more, so although we used 349kWh during the month, our meter shows we only imported 197kWh, so we did not have to buy 152kWh making a saving of about £19.31 off our electricity bill at the new import rate of 12.71p/kWh since 3/3/11


30/4/11 - April was fantastically sunny and warm, we generated 563.2kWh, again well above the PVGIS estimate of 492kWh. We also have got used to using the washing machine and dishwasher when its sunny and saved £23.89 on our electricity bill this month.



Total earings and electricity savings have now exceeded £1000 since September with the best 4 months still to come, hopefully.



31/5/11 - May was again very sunny, if not terribly warm, we generated 611.7kWh which was 8% above the PVGIS Estimate. We also saved £24.53 off our electricity bill.


The above graph is from a website where all the data from our panels is now posted. The live data from the panels can be accessed here; This site also shows historical data since installation, but only daily data since the beginning of May. It can also show figures for our energy consumption and how much electricity we have saved on a daily/monthly basis.


1/6/11 - EDF emailed us to request a meter reading for the quarter, we generated 1586.2kWh during March/April/May, which should equate to a payment from EDF of about £700!! Making the total income since installation of £1306.34, which includes an electricity bill saving of £113.16 - not bad for 9 months and well inline with my original estimate/guess of £2000 for the first 12 months. Hopefully the next 3 months are as good as the last, in theory it should be 18% better than March/April/May, according to the PVGIS estimates.


19/6/11 - The total generation since installation has just exceeded the UK Govt. SAP PV estimate for the year of 3066kWh for our specific system. Obviously this is a grossly conservative figure as we have nearly 3 summer months to go until the end of our first year. The SAP estimate is what has to be given by the installers so they do not try to over estimate income, it doesn't even take into account where you are in the country, or local climate, which is why its so inaccurate. The PVGIS Climate annual estimate of 4270kWh, however, looks like being much closer to reality so far this year, we are on target to just exceed it if all goes well. The best day so far was June 11th with just over 29kWh of generation.


30/6/11 - June was patchy, some good sunny days, but quite a few dull and misty days. Overall generation was 556.7kWh making a total of 3268.1kWh since installation. The monthly total was 5% lower than the PVGIS prediction of 588kWh, although the overall figure is still 3.2% above the predicted figure since installation. An electricity saving of £24 during the month is much better than expected with our import costs down to only £14.23.


Total income and electricity savings = £1580.59 for the 10 months since installation.



The Daily output graph above for June, shows the Generation as normal in green, with Export in orange and Electricity Saved in blue all in kWh. Interestingly the worst generating days have the highest proportion of self usage [Saved] as practically nothing is exported.


31/7/2011 - July was pretty good for generation, but most people would say it was a poor summer month. We generated 565.1kWh which was 2.4% below the PVGIS estimate, although overall generation since commissioning at 3833.2kWh is still 2.3% above the PVGIS Estimate.



 Next month being the 12th month since installation will be the last monthly update, I will post quarterly or when any significant occurs from then. The Monthly statistics will continue on the PV Statistics Page. 


31/8/2011 - August was dull and cold, but only 3% down on the PVGIS estimate with 483.7kWh being generated during the month [499kWh Estimated]. Total since installation is now 4316.9kWh, with 2 days to go till the end of the first year.


August Total Generation 483.7kWh

EDF sent payment of £700.93 in payment for the 3 months to 1/6/11 a few weeks ago.



3/9/11 - One Year Old Today


4357kWh's were generated during the year which has produced an Feed In Tariff/Export Tariff income of £1931.18 plus an electricity bill saving of £186.84, making a total income of £2118.02 for the first 12 months. This represents a return on investment of 13.66% as against 2.5% if the money was left in a Building Society, for investment comparison the FT SE 100 is 5292 today which is down 2.5% since 3/9 last year.

Basically the Solar Panels are paying our Electricity and Central Heating Oil Bills!!

The year has been about average overall weather/Sun wise, with a very good spring, but a pretty dismal summer, so my own estimate back last Sept. of 4300kWh was pretty accurate, much better than the Govt.'s estimate of 3066.62kWh which was only 70% of the actual total of 4357kWh. The PVGIS monthly estimates have been very accurate with only a 1.7% difference over the whole year. We are lucky to live in such a good area for sunshine and this combined with the very generous Feed In Tariff have made it a fantastic investment that I would wholeheartedly recommend to anyone with a vaguely South facing roof. The prices have come down quite a lot over the year and a system similar to ours would now cost between £10-12,000 which would give an return on investment of well over 20%.

Although our Tariff is fixed, except for inflation rises, the tariff for new installations is to be reviewed and will change April 1st 2012, my guess is our tariff will rise to over 46p per Kwh because of inflation, the new tariff will drop to about 25p which at today's installation costs would still be about 10% return. So if your thinking about it, get it installed before next April!! - You Know it Makes Sense.


Update 28/10/11 - Looks like the tariff will drop dramatically for new systems from the 8th of December, 4 months earlier than expected!!!!!


Update 31/10/11 - It has been confirmed today that New systems from 12th December will receive 21p per kWh generated as against 43.3p for systems completed before that date. This has been done as the installation costs have reduced dramatically, so a 4kWp system may cost as litttle as £10-11,000 now, but was £15,000 a year ago. So the investment return which has recently been as high as 20% in this area will be reduced back down to the approx. 10% the FIT was supposed to have yielded when first announced  in 2010. Overall I think the new rate is about right, but the Govt. should have gradually cut the fit over the last year rather than leaving it this long and risk killing off the fledgling solar PV industry with a panic 55% cut. - The Ed.


23/11/11 - Now that the shock of the FIT reduction for new installations has sunk in I have worked out what return last years generation would earn at the new rate of 21p + 1.55p Export tarif [3.1p for 50% of Generation] + the same electricity saving of £186.84. The total would come to £1169.34 for the year. This sounds a lot worse than the £2118.02 we actually earned, but the installation cost has reduced considerably. With 4kWp systems currently being quoted for the New Year as low as £8,500, the return on investment is almost exactly the same as our system at 13.7%. So don't think its too late and you have missed the boat, its still a brilliant investment IMHO, just make sure you get a good deal on the installation. The Ed.


12/12/11 - New FIT rate of 21p comes onto force for NEW systems installed from today.


22/12/11 - Govt. Loses court case regarding FIT decrease - Nobody knows what's happening!!


31/12/11 - Total Generation for first full Calender Year = 4362kWh from 1/1/11 to 31/12/11.

Slightly higher than the 4357kWh during the first 365days, but remarkably close.

Total Generation to date = 5226.1kWh with a total income/savings of £2564.10 which includes an electricity saving of £243.10. Out of interest the 2nd increase in electricty price this year, in November by EDF, has added 15% in total this year!! It was 11.31p in Sept 2010 when the system was installed and is now 13.10p



As mentioned in October 2011, I shall not bore you with monthly reports from now on, but if there are any notable events, I shall post them here. I will continue to post the monthly results on the Solar PV Statistics Page and on where you can see all the live and historical data/graphs. - The Ed.



27/3/12 - Feed In Tariff Change - After all the legal wrangling has finished with a resounding loss by the Government, the situation is now that new systems upto 4kW installed after 3rd March 2012 will receive 21p per unit generated. This is likely to be reduced further in July and then again in September. The good news however is that because installation prices have reduced considerably the return on investment is very similar to ours. Current prices are about half of what they were in September 2010, so a 21p FIT rate will still have a return rate of over 10% which is inflation proofed and guaranteed for 25 years. The recent legal cases have shown that the govt. have no powers to retrospectively reduce the tariff for existing installations.


The range of FIT payments for the next year are summarised by the DECC here;


Install between 3 March and 30 June and you’ll receive 21p per kWh.
(Be aware that from 1st April Energy Performance Certicate (EPC) will be required with Level D or above.

Install between 1 July and 31 September and payments may drop to 16.5p-13.6p per kWh.

Install between 1 October 2012 and 31 March 2013 and payments may drop to 15.7p-12.9p.

Install from 1 April 2013 and payments may drop to 14.1p-11.6p.


One further change which comes into effect on 1st April is that to receive the full FIT rate, new applicants will need to have an "Energy Performance Certificate" with a D rating or higher. This should not be a problem for most properties, but has been a big problem for our local Church which is unlikely to acheive this level. I was asked by the Church to advise on the suitability of the Parish Church roof last year and despite Adam from SolarFocus trying his best to get the Church system installed before the deadline, it doesn't look like it will be feasable to beat the deadline and there is little or no chance the Church can be insulated enough to get a D EPC rating. - The Ed.


1/4/12 - Existing installations get 47p from Today.

Those of us who installed before 3/3/12 will have their Fit payments increased by inflation so that with 50% deemed export the total payment will be 47p per kWh generated. - The Ed. 


1/6/12 - July Deadline Delayed

The 1st July deadline for the next drop in FIT rate has been delayed until 1st August. The new rate will be 16p per kWh generated for 20 years instead of the 25 year contracts upto that date. The Export tariff has however been inceased to 4.5p, from 3.2p, but only for new contracts from 1st August. The new 4.5p export tariff apparently matches the wholesale price of electricty according to my sources.- The Ed


16/6/12 - The Price of Oil on the Island & Greener Alternatives.

On an unrelated note and definitely not Green, I filled up with Central Heating Oil the other day and had a look at a national website which gives quotes for oil in your postcode and so I duly put in our postcode and got a price similar to Vectis Oils, but as a test I put in my parents Mainland postcode in Essex and was astonished how much cheaper the same tankfull of oil was. It was about £345 less!!!!, how can they possibly justify that sort of premium, I could hire a tanker and go and get it from the mainland for that sort of difference!!

I have been looking at greener solutions to central heating than oil, but I'm not sure I can be bothered with loading woodchip pellets into a biomass boiler and the heat pumps available don't yet convince me as they only seem to be suitable for houses with underfloor heating permanently on. The Govt. have been touting the Renewable Heat Incentive for a few years, but it has yet to start or be finalised. The RHI is supposed to work a bit like the FIT for Solar PV, ie. they pay you to be green, but no firm figures have been released yet, the scheme which was supposed to have started in 2011 is now due to start in 2013.- The Ed


30/6/12 - One Month To Go Before Next Tariff Reduction.

Speaking to Adam from SolarFocus yesterday, he said they have been getting very busy again in the run up to the next tariff drop at the end of July. With Adam quoting current installation costs of between £6000 and £7500 for a standard system the rate of return is now actually higher than when the Feed in Tariff started. It will still be very good after the next deadline as the drop to 16p is not as great this time, but the tariff for new applicants will only be payable for 20 years instead of the 25 years for systems registered before 1st August. The other change Adam mentioned is the availability of new 333W panels from SunPower, meaning only 12 are required to get a 4kWp system instead of the 22 180W panels we have. This also means that people with a smaller roof area can still get a reasonable size system.

The June generation at 460kWh this year is well below the 557kWh last year, which in itself was not a very good month last year, the estimate being 588kWh. Still 460kWh still seems remarkable as we hardly ever saw the sun during the month!! - The Ed.


3/9/12 - Two Years Old Today - Income Higher Despite Poor Summer!!


Total generation for the first 2 years is 8525.1kWh, which is a total income and bill saving of £4250.

The last 12 months have not been as good as the 1st year with a generation of 4168.1kWh as against 4357kWh for the 1st year, but considering how bad this summer has been it is still surprisingly good. That equates to 188kWh less generation, but because the tariff has increased the actual income over the year has increased by about £14. - The Ed.


15/1/13 - New FIT Rate for Existing Pre March 2012 PV Systems

The official RPI inflation rate has been announced today at 3.1% for 2012, which means from April 2013 the rate payable by the Energy Suppliers will rise to 48.45p / kWh in total. This is made up of 46.8p FIT and 3.3p Export Tariff which equals 1.65p for 50% Deemed Export. The current rate total is 47p/kWh since April 2012.  The previous years' total figures including 50% export tariff were 44.85p and 42.8p for 2011 and 2010 respectively.


12/7/13 - RHI rates announced

The government have announced the rates for the Renewable Heat Incentive due to start next spring [2014]. These are the amount paid by the Govt. for homeowners installing Renewable Heating systems based on the deemed amount of heat that the property is likely to use over 20 Years, but paid over 7 years. This system is similar to the Feed in Tariff for Solar PV, but this time paid for Space heating and domestic Hot Water generation utilising "Green" energy sources such as Heat Pumps, Solar Thermal Panels and Biomass Boilers using wood pellets/Chips.


31/7/13 - Best Month So Far

With 628.5kWh generated during the month, July 2013 has been the most productive month since the system was installed. 18 consecutive virtually cloud free days during the month produced the record total. If it not been so hot the total would have been higher as the panels loose a small amount of efficiency as they get hotter. Amazingly the system is within 1% of the predicted total generation for the last 3 years, based on the PVGIS calculations.


3/9/2013 - 3 years Old Today 

Total generation for the first 3 years is 12777.2kWh, which is a total income and bill saving of £6475. This corresponds to just under 51p per kWh all in.

The last 12 months have not been as good as the 1st year with a generation of 4252.1kWh as against 4357kWh for the 1st year, but better than last years 4168.1kWh for the second year. Amazingly the average per year at 4259kWh is 13kWh short from the computer modelled estimate of 4272kWh.


For Reference FTSE = 6513, which is 20% higher than 3 years ago so a similar amount to the cost of the panels would have risen by £3100. So the panels have earned well over double an equivalent FTSE investment, although it has to be said that with the FTSE investment you could withdraw your investment and earnings at any time. Whereas the Solar investment the original investment is virtually impossible to "withdraw". With the FTSE investment there may well have been some dividend income, but there may also be some tax implications.


31/12/13 - End of 3rd Full Year - Total for 2013 = 4156kWh lowest Yr to date, but highest in terms of FIT Payments at just over £2000. Total generation since installation in Sept 2010 = 13576.6kWh with a total FIT payment and Energy Saved of £6933.01


14/2/14 - New FIT Rate for 2014 Announced

The new FIT rate from 1/4/2014 will be 49.765p/kWh inc the Export tariff [48.07p + 3.39/2p export], which is an annual RPI inflation rate of2.7%.


10/4/14 - New Electricity Tariff


In anticipation of installing an Air Source Heat Pump when the RHI starts I changed our Electricity supply tariff from EDF's Eco20:20 tariff with a day rate of 14.54p and a night rate of 11.61p to OVO Energy's single tariff at 11.34p all day/night. The standing charge is slightly higher, but even with our 2280kWh annual usage its still cheaper. The savings will be greater when the oil boiler is replaced as our electricity use will increase dramatically.


18/6/14 - Solarimmersion III installed along with a Panasonic Air Source Heat Pump


The full story of the heat pump installation can be found on the "Renewable Heat Incentive" page on the website here:


The Solarimmersion III is a device which measures how much solar PV generated electricity is being exported, ie not used in the home, it then divert most of this excess directly to the immersion heater in the hot water cylinder. The really clever part is that although the immersion heater is rated at 3kW, the diverter can send any amount of power to it and it will add to the heat in the cylinder. So if you are generating say 2kW and the house is using say 500W the diverter will send 1480W to the immersion. Obviously this will take longer to heat up than if the immersion had the full 3000W, but it all helps to heat up the tank. If the sun comes out and you are genearting 3500W and the house is using 500W then the immersion gets its full 3000W and the tank heats up at normal speed untill the sun goes in or the tank's thermostat cuts in.


The graph above shows the solar generation in Green being matched by the house's consumption in Red from about 6.30am to about 5.30pm on a reasonably bright, but cloudy, mid June day. The Heat Pump was being tested from about 4.30pm on this particular day, which is why the consumption goes way over the generation in a series of peaks until about 7.00pm. The other high peaks in consumption during the day and evening would be the Kettle or cooker being switched on, the top line is 3500W, each grey horizontal line is 500W. Not being a sunny day meant the hot water temperature never reached the immersion's thermostat cut out of 68C, so the solar immersion was pumping in what power it could nearly all day. The tank temperature reached about 60C on this day and was still well over 40c the next morning after various showers etc.


On this particular day the Solar PV generated a total of 11.78kWh, the house consumed a total of 15.75kWh, but only 1kWh was exported. 4.9kWh or units of electricity were imported at 11.34p/unit = £0.55, whereas the FIT/Export income was £5.85. Because of the way the FIT export is deemed, ie 50% of generation, it doesn't matter whether you use the generated electricity or not you still get 50% of the generation for export. In the past before the Solarimmersion was installed we exported about 70% of generation, but it will probably reduce to about 50% in summer on a sunny day down to about 1% on a sunny day on winter.


3/9/14 - 4yrs Old Today

The system has been running for 4 years now and has generated a total of 17271.5kWh, which is 4494.3kWh in the last 12 months. This is the highest yearly total so far, beating the first years 4357kWh, due to the very sunny summer. The total FIT income so far has been £8100 which with electricity savings takes the total to £8943.15!! The electricity savings will be much greater from June this year due to the SolarImmersion and Air Source Heat Pump installations as we have moved away from Oil for Hot Water and Central Heating, so we will be using a higher percentage of the Electricity generated ourselves rather than exporting it. Since June our Hot water has cost almost nothing, whereas we would have used at least 100 litres of oil [about £60] in that period.

3/9/15 - 5yrs Old Today

The system has been running for 5 years now and has generated a total of 21576.7kWh, which is 4305.2kWh in the last 12 months. The year was on course for another record year until the dismal July and August, but still above the estimated 4272kWh by PVGIS or my esitmate of 4300 from nearly 5 years ago. Total income is now £11455.44 including £1200.29 electricity savings, which is 74% of the initial outlay, so approx another 1.5yrs before the initial outlay is repaid excluding interest lost. 

3/9/16 - 6yrs Old Today

The system has been running for 6 years now and has generated a total of 25,800.7kWh, which is 4224.00kWh in the last 12 months.  Total income is now £13967 including £1538 electricity savings, still on course for simple payback by middle of 2017. I received an unsolicited letter yesterday from a company offering up to £20,000 in a lump sum to buy the panels and hence the remaining 19 yrs of FIT payments, I will obviously not be replying, but interesting that they are being valued seriously. The average FIT payment per annum so far has been £2071.50 over the first 6 years excluding any additional electricity saving, so they are offering less than half the total expected FIT payment up front.