Solar Blog 2012


The plan to switch to EON didn’t go well. They tried to charge me more than I thought I had signed up for, well I did sign up for actually, I have the printout so I told them where to go and let Scottish Power keep my business. If nothing else their Call Centre people are always very helpful though maybe it helps that I once worked in Glasgow and know the dialect fairly well. The price has gone up rather a lot since my last contract with them.

December started well and then went right down the drain. The year ended 120 kilowatt hours down on 2011 even though it was seven days shorter due to the installation date and the Leap Year.

Month’s generation : 86·38 kWh.


My supply contract with Scottish Power ends on 3rd December so I looked around for a replacement and found EON to be cheapest for me, they have actually said they will take a smaller monthly direct debit than Scottish in recent months. I have used EON before and they were perfectly OK apart from several times trying to raise my direct debit payments and getting the arithmetic wrong.

However the interesting thing is that Scottish Power said I had used 2,552 units of electricity in the past 12 months and in the year before the solar panels were installed the figure was close to 7,000. That cannot all be due to the solar installation, I switched most of the house to low energy lamps and turn the desktop computer off more often than I did, and maybe the home cinema gets used less often than before.

Month’s generation : 140·33 kWh.


The hopes of exceeding last October’s output rapidly disappeared after the 17th when the sun disappeared and wasn’t seen again in the South East of the country for the rest of the month.

My neighbour who has a system 4% bigger than mine saw his output fall to less than 80% of my own by the end of September and it wasn’t difficult to trace it to a tree at the 11:30 a.m. position some 35 feet tall and 30 feet from his house. In high summer the sun looked over it but not in Autumn. Having had it removed at a cost of about eight months’ electricity his output is now back up at 104% of my own where it should be.

Month’s generation : 197·58 kWh.


The year’s prediction total was achieved on the last day of the month, last year it was achieved on the 26th September. This may sound like a good score but it overlooks the fact that system installation wasn’t completed until the evening of 6th January last year and 2012 is a leap year. So that’s a seven days advantage for 2012 and production is still lagging four days behind. But with no Summer to speak of it's a lot better than one might have guessed.

Month’s generation : 360·31 kWh.


There’s no further chance of any day going over 20kWh this year, so that makes nine in 2012 against the 13 of 2011.

Month’s generation : 403·58 kWh.


Another rotten month. By day 213 of the year (31st July) generation reached 2065·97 units. On the equivalent day last year the figure was  2283·22.

Month’s generation : 395·68 kWh.


A rubbish month by any standards, it is surprising to have got anywhere near the 100% of prediction mark given the absence of sunshine, but it wasn’t the only PV disaster this month.

When my system was installed I thought it would save money to use a low powered kettle, more likely to draw current within the panels’ normal output. However when I discovered that my meter was prepared to feed the mains as if the grid was one big battery there was no point in having a 750 watt kettle. That situation changed with the new meter and the kettle was brought into use. After fewer than 20 uses it failed. The light comes on but the water stays cold. I won’t be buying anything from Russell Hobbs again.

The generation meter continues to run nearly 1·4% ahead of the inverter reading recorded below and elsewhere.

Month’s generation : 359·11 kWh.


Since the two colour Month graphs were introduced last month the blue of the Month histogram hasn't matched the shade of the Day histogram. This was rectified on 5th May but will not be applied retrospectively. It will cause the full year display to become two tone blue but is far too labour intensive to put right.

The panels were disconnected from about 09:40 until 10:00 on 16th May while the main electricity meter was changed, it being 25 years old.

May has been the second worst month on record - with reference to the prediction - but also included the second best day ever, and the third. A bit of a disaster overall that will likely have a big impact on the annual achievement.

Month’s generation : 368·62 kWh.


On the first of the month the website was rearranged so that solar data takes precedence, it no longer appears within a folder named ‘solar’. All bookmarks, favourites etc. should automatically redirect and reach the correct page. Browser History files and cached pages may play havoc with this until they expire or are cleared.

On the 3rd, and following an apparently successful attempt to deter pigeons with mesh between panels and tiles, the gutter was cleared of up to two inches of pigeon poo and twigs. While there it was observed that the panels were filthy with a layer of sand or similar which had also adorned cars recently. They were given a good hose down two days before the hosepipe ban came into force.

On the 16th the software that produces the Month histogram was modified so that days are shown in red if they fail to meet target. Blue if they do. At the time of writing it has some issues - the shades of blue appear to vary.

EDF Energy popped round to say my meter needs replacing as it is 25 years old. This is true, I moved here to a new house on 7th May 1987. They offered to do the job straight away but the rain started to tip down again and the installer decided he’d rather do something else. The software problems that caused the Month graphs not to go red when required seems to have been fixed, by the simple expedient of sending the routine round the loop twice. It appears to be a function of Excel 2003. A single loop works fine on 2007.

Month’s generation : 318·07 kWh.


On the 2nd a fourth solar installation arrived on the local scene making four houses out of six in the road. It is 4% bigger than mine and achieved by placing panels closer to the roof edge than is generally considered advisable. The roof is absolutely identical to my own but with a very slight chance of shading by a tree. It is also about 15 feet nearer the equator but not otherwise different! His generation meter is generally registering four to five percent higher than my inverter records, and as that registers about 1·2% lower than my generation meter that is exactly what one would expect.

The pigeon man came back on the 20th and took away all the spikes and replaced them with a heavy gauge mesh which has been clipped to the underside open aluminium edge of the panel frames. It has been cut to follow the tile contour. He did the same for all four installations in the street.

Immediately afterwards I saw up to six pairs of pigeons looking very puzzled but they are beginning to go away. By the end of the month their number was usually reduced to only one or two pairs.

On Monday 26th the inverter was moved to a more convenient position; hence the lack of output on a sunny morning. A new garage door is to be fitted and its track is wider and lower than the old one.

Within the next few days I intend to take this website out of the solar folder at this domain and install it in the root. The remainder of the pages at the domain will be transferred elsewhere. I shall attempt to set the redirects appropriately but if it proves to be too complicated you may have to change your bookmarks, links etc.

Month’s generation : 322·65 kWh.

A close neighbour with an identical house asked my supplier, Solstice Energy, the price of a system the same as mine. £10,013 with a power increase from 3·29 to 3·5kW. It would appear that I would have been better off if I had not invested in solar a year ago. (Price reduction of £2,000, FIT and power supply savings slightly under £2,000 and interest lost on the capital sum.)

There is a new problem with vermin getting under the panels. I have heard the noises before but now I have seen what causes them. A hungry squirrel goes under the panels and comes out with pigeon egg on his face. I’m not sure whether the squirrel is to be welcomed or not.

The 29th saw my neighbour’s new system begin installation making the numbers four out of six adjacent houses. I took the opportunity to go up on to the scaffold for a closer look but it was the west facing installation next door which caught my eye. Its cables were hanging loose over the roof and not concealed by the panels. Far worse was that the corner of three panels are badly damaged and have gone a white opaque shade where one would expect that deep bluish colour. I have heard the system is doing very badly which I had put down to the westerly aspect but now I am not so sure. I understand that the system was put in by a gang of Eastern Europeans who spoke no English. I think my pigeon problem is probably minor by comparison.

The new owner looked into Rent a Roof before eventually buying his own panels. An agent for a company called Future Roof offered to install PV for nothing on condition he pressure washed the yellow lichen from his concrete tiled roof first. The price quoted was £7,200. Can they be serious? The new installation cost only £2,000 more.

Month’s generation : 184·91 kWh.

The sixth of the month marked completion of one year of generation. The meter reading was 3435·6, the data logger recorded only 3396·82. Generation for a complete year is therefore 21·38% above prediction.

14th. Investigated pigeons congregating on roof (lower left). One section of pigeon deterrent fallen off, adjacent one about to do the same. Pigeon access point thereby provided. Microbee’s use of ‘No more nails’ as an adhesive is a bit of a disaster. It sticks very well to the panels but not at all to the plastic base of the deterrent spikes. Detached deterrents refixed with silicone mastic. Next day see one pigeon trapped inside. Tough; it will have to suffer the consequences of its own actions.

And then another section of pigeon deterrent fell off…

Month’s generation : 116·93 kWh.