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Photovoltaic Solar Panels

August 2009

The government recently announced that they are introducing a Feed In Tarrif for small scale electricity producers. This makes solar panels a financially viable means of generating our own power. Basically, for a system under 4kw they will pay 36p for every unit that is generated for the next 25 years, regardless of whether we the power ourselves or sell it back to the grid. Our current thinking is that we could potentially earn £1,200 annually from the government and also reduce our electricity bills by £300 per year. With the £2,100 grant the system could pay for itself in about 10 years. We tried to get a few of quotes but the only company that actually came out to see us was Solar Focus. Adam was a very nice guy and came back with a price of £18,300 including VAT for a 3.96 kW system using Sharp panels. After the grant the cost to us would be £16,200 with a potential payback time of just under 11 years (excluding the interest on the money borrowed to pay for this). Time will tell...

September 2009

We contacted the council and paid for a report on the history of York Cottage and also to find out if solar panels would be covered by the "permitted development" rules. They took months to respond!

October 2009

Because the panels will be located on the games room roof we had to make sure that they were not in shadow. This unfortunately meant removing the old sycamore tree in the front garden. It did however provide a few year's wood ready for when we get the new stove installed in the front room.

The installation of solar panels also requires a connection to the main fuse board which is 20 metres away in the house. We therefore had to dig a trench to bury a new 10mm armoured cable running from the house to a new fuse box in the games room. We had to be careful not to dig up the mains water pipe but Izzy of course made digging through the clay and flint a relatively painless job. However...

What a nightmare! Every step of the games room building work has led to even more work being required. We did not realise just how badly the building had been constructed. The roof which was supposed to hold the panels had only eight trusses and five of those were above the garage leaving only three trusses to span over 10 meters. This obviously resulted in the roof sagging and because the roof had also been built incorrectly the walls had been pushed out. The end result is that 80% of the games room will need to be completely demolished and rebuilt before the panels can be fitted!

November 2009

The solar panels were finally delivered and installed although we weren't too impressed with the final fixing which would not have been water tight. Calls to Schuco technical support backed up our concerns so Solar Focus had to come back and make good the installation. They had left open bolt holes and gaps in the central track which would simply fill with water and pour onto the felt, felt that was damaged when they put their foot through the roof. One of the central track pieces wasn't secured down properly, with no butyl tape underneath and the expensive flashing was badly fitted without enough overlap. Unfortunately I felt the installation was poor.

However, they still did not have the inverter so the panels could not be connected and were basically very expensive roof tiles. In fairness to Solar Focus, the whole industry is complaining about supplies because Germany seem to have bought up most available stock in Europe. However, the panel installation did mean that the roof tiles could finally be fitted and the whole room could begin to become water tight. But even this was delayed because the special 20:20 tiles were not ready for delivery and when they were delivered they did not provide enough.

December 2009
The inverters finally became available so the solar panels were connected up on the 14th December. The electrician came back in the afternoon of the 15th to actually turn the system on, after I phoned to express concern that nothing was happening. I don't know why they left the system de-activated, but at least the panels finally starting to pay for themselves. We had a particularly snowy night on the 17th (we had to walk home from the centre of Maidstone up Detling Hill and through the driving wind and snow after the company Christmas meal) but the 18th turned out to be very sunny so I went outside and cleared all the snow from the panels and then experimented with our power useage. I turned off all the fuses in the house and looked at our old mechanical electricity meter. I have not asked EDF for a new meter because it is our interest to keep the new one as long as possible. To see the wheel spinning backwards faster than it normally goes forwards was a fantastic feeling! Basically we were exporting power back to the grid at the same value as we buy it. With the new meters they log import and export seperately and obviously the power companies do not pay for exported electricity at the same rate as they charge for imported (about 3p rather than 9p per unit). The old electricity meters simply wind the dial backwards so you effectively get exactly the same price for both.

Anyway, after this first experiment we then turned on the household circuits and to my surprise, even with everything running, we were still generating more than we were using and exporting power to the grid. That was with the airsource heat pump working, Luke on his Playstation, me working on the computer and all the usual clocks and gadgets plugged in. However, just turn that electric heater on and see the dial instantly whizz the other direction! There is a chart below to monitor the electricity generation.

Unfortunately we have also noticed that the fittings on the solar panel flashing are already rustings and leaving brown streaks.

March 10
Solar focus came in and removed all the panels then installed a brand new mounting system and another membrane under the panels to channel any water that gets in back down and onto the bottom flashing. This was a top quality mounting system so must have been expensive for them, but it seems to have resolved the leaks. Although there have been some issues with the installation I can say that they have remained eager to ensure that everything is working fine and that we are happy with the result. I think customer satisfaction is high on their list of priorities so I am more than happy to recommend them.

April 2010
Amazing! April was sunny and warm so we turned off the underfloor heating. This meant that we actually generated 1 more unit than we used during the day. Our month end meter reading went down for the first time. Who knows what it is going to be like over the summer!

July 2010
I noticed that the generation since April hasn't been going up by much and considering the amount of sunshine we have had I was surprised. I checked the inverters and the secondary inverter has gone down. This means that we are literally generating only half the amount of power that we should. I don't know how to find out when the inverter stopped working but from the drop in generation and the increase in sunshine I think it must have been some time in May. I put a call into Solar Focus and they got back to me straight away and then came in the following day and replaced the slave inverter. The system immediately sprung into life and started pumping out twice the amount of power. However, the master inverter must have had a fault because two days later it was burnt out. Luckily this did not spread or we could have had a serious fire on our hands! Now waiting for a replacement master inverter to arrive. We calculate that if the slave went down in May as the figures suggest then we must have lost about £500 worth of electricity generation.

August 2010
The day after getting back from holiday (9th) the new inverter was installed and the system was moved into the garage where we can keep an eye on the status. Although we lost the generation for almost a third of this month it will be interesting to see how the system performs for the remainder of August.

May 2011
Exceptionally dry and sunny during April and May, the hottest and dryest on record, so generation was particularly good.

September 2011
We can see how the night time electricity useage has rocketed due to the Leafs, as well as a slight increase in the daily use, but this is still far cheaper than buying petrol! The electricity cost for 1000 miles is about £15 compared to £140+ for petrol or diesel. The daytime use in September is 342 units compared to 323 last year, while the night time use has more than doubled from 146 units last year to 329.

April 2014
Our old electricity meter has now been changed for a modern digital unit.