Your home will still be connected to the National grid. If your solar panels are producing less electricity than your home is using, or at night time, you will receive electricity in the normal way.
No. In Solar PV panels the glass protecting the solar cells has an anti-reflective coating which greatly increases the transmittance through the glass to maximise the light reaching the solar cells. The outer face of the glass has a slight granular texture also intended to maximise yield. These two characteristics greatly reduce reflection from the glazed front face of solar PV modules.
Solar PV systems have no moving parts and require no maintenance. Most of the time the rain will keep the modules clean. However, a build up of dirt can affect system performance. The degree of soiling will depend on the location but usually dust accumulation and self-cleaning reach a steady state after a few weeks if the array tilt is at least 15 degrees.
A basic PV module (interconnected, enclosed panel of PV cells) has no moving parts and can last more than 30 years. There are examples of 35 year old systems operating at 95% of initial specification. Most manufacturers guarantee panels to operate at 90% of specification after 10 years and 80% after 20 years, i.e. 1% degradation a year. The best way to ensure and extend the life and effectiveness of your PV system is by having it designed well installed & maintained properly.
Most problems occur because of poor design or sloppy system installation, e.g. failed connections, insufficient cable size, components not rated for DC application. The next most common problems are failure of the electronics in other components of the systems e.g. inverters, which typically come with a 5 year warranty.
By ensuring your system has maximum exposure to the ultimate energy source, i.e. the Sun. So you must ensure the system is orientated due south, there is no shading; the PV panels operate at their optimum temperature. To make the electricity you produce go further change when you use electricity in the house, e.g. put your washing machine on a delayed cycle so it comes on during the middle of the day when you system is generating lots of free electricity.
To tell if solar electricity is right for you, there are a few key questions to consider:
Yes of course. However unless you are an electrical engineer roofer or builder we suggest using certified professionals to design specify and procure quality components and install these using sound engineering and installation practices, for the following reasons:
If it’s not possible to achieve the optimum angle PV systems will still produce over 90% of the maximum energy at 10 degree and 50 degree tilts. South-facing vertical facades generate around 70% of the maximum, e.g. if panels are mounted on south facing walls.
The best angle from the horizontal to tilt panels is at the same angle as the latitude, minus 10-15 degrees. So, 30 degrees is an optimal tilt in Southern England, increasing to almost 40 degrees in Northern Scotland. The maximum solar radiation will be obtained by orientating panels due south.
Shading is important. Solar panels are connected in series, one shaded panel in the string can reduce overall productivity. If a panel is shaded bypass diodes will reduce the impact of that panel’s lower output on the total system voltage. We always check if the roof on which you propose to install Solar PV is affected by shade & take this into account when estimating potential PV productivity.