Bruton Town Council has been supporting the installation of solar PV systems provided by IDDEA. We decided to use them, opting for a standard 12 panel system plus a 5.2kWh storage battery. I’ve written this article for others who may be considering installing PV. I would be happy to answer questions from anyone thinking of doing so.
Survey and installation
The process started with a visit from an IDDEA surveyor. They checked that the roof has the right orientation for the panels and went through every detail of the installation to make sure that the installers had the right equipment for the property. (Will scaffolding be needed, is there loft access and is it wide enough, can lorries get to the property etc etc?) The surveyor prepared a detailed quote, which as well as price, estimated likely electricity generation.
Our installation took a day and a half: slightly longer than they expected. There were two separate teams: an electrical team who install and wire in the inverter and battery, and the roofers who put the panels up. All the workers were polite, friendly, and neat and tidy in their work. Apart from the attic there was no need for internal wiring, with just one extra cable running down the front of our house to the electricity meter.
The paperwork (guarantees etc) took some time to arrive after the installation. There also turned out to be massive bureaucratic delays in getting set up to sell electricity back to the grid which are nothing to do with this particular company.
The standard 12 panel installation cost £4,000. We paid a further £3,000 for the battery.
The panels are neutral and unobtrusive in appearance. They couldn’t be described as improving the appearance of our property, but neither are they a total eyesore.
The GivEnergy inverter and battery both look very stylish and modern, but we are glad they are in our loft, as there are lots of additional wires and little boxes that go with them. They are large and hefty things (inverter on the left, battery on the right).
Operation and performance
The system runs itself with no input from us. It does not need maintenance. The inverter automatically feeds solar energy to the house, to the battery till it’s full and then any surplus to the grid. It decides which source to use (panel, battery or grid) to power the house at what time. This is ‘smart’ technology: the system is monitored and controlled by an App, and with this particular system it’s possible to choose when the battery discharges. The App gives details of what’s happening right now and can also give detailed reports of performance over time. More detailed reports are available online.
Our system was installed at the beginning of June, nearly midsummer, so we are seeing its peak performance. The theoretical maximum power generated by 12 x 350 W panels is 4.2 kW. We have eight panels facing southwest, and four facing south-east: a good but not ideal orientation, particularly as the southeast facing panels are shaded early in the day. Despite this we have generated the theoretical maximum a couple of times, and on any sunny day we regularly get between 3.5 and 4.0 kW between 12.00 and 2.00 pm. 8 July was mostly sunny, but with a few cloudy episodes which can clearly be seen.
We are fairly low users of electricity. Over the 12 weeks since our installation, the panels have generated well over twice what we use. (Our average use has been just over 7 kWh per day, our average generation nearly 17 kWh). This will not remain true at other times of year. The following screenshot shows 10.00 am on a sunny morning (10 August). We have just run the dishwasher, and at this point in the day have consumed more energy than generated. Over a year, we hope to generate as much as we use.
The battery is fully charged by mid-morning on most summer days. The stored energy sees us through the evening and overnight. If there’s high usage at any one time (such as oven and electric kettle at the same time) the system tends to call on the grid. Nevertheless, on average we have spent less than 10p a day on electricity since installation (plus a standing charge). We have just started getting paid for electricity generated, receiving £6 for the first week. In summer at least we will get back more than we spend. We hope that over the year we will break even.
The consensus is that solar panels pay for the cost of their installation in anything from 8 to 14 years, well inside their 20-year lifespan. There is a geeky debate about whether batteries ever make economic sense.
We bought our system to play our part in low-carbon energy generation, rather than to save money. It makes sense to us to generate our own electricity where it is used, and a shame to waste all the free solar energy hitting our roof.
So far (and it’s early days), we have been pleased with the installation and with our system. We didn’t look at competitors, but this system appears good value for money.
Cllr James Hood
To confirm, during the time that the energy went back to the grid for free, you will not get paid for that energy simply whatever goes to the grid from when you managed to get it set up to pay you for your excess output.
Yes. The system automatically sends excess power back to the grid when it is generating more than is needed to power the house and charge the battery.
We didn’t get paid for this until we had jumped through several bureaucratic hoops. This is a UK-wide issue, and nothing to do with this particular installer, who did their bit on day one. I understand that it typically takes from one to two months to get the export payments set up. Two months in our case.