We are sure you will have many questions regarding Solar PV Panels and the Feed in Tariff. Below we have answered the most common questions. If there’s anything else you need to know simply call us on 01422 369004 or complete our contact us form and we’ll get back to you.
What size PV system do I need?
The size of PV system installed depends on how much you want to invest, how much of your electricity you want to generate from Solar PV and whether you are limited by unobstructed roof space
Most people install a system between 2 – 4KWp, which will generate between 1700 – 3500 kWh per annum. It is estimated that a typical family home will use 3300kWh per annum, so a larger system will provide most of the electricity an average family will use. It is not essential to provide all of your homes electricity via solar PV since you will still be connected to the national grid, even half will make a serious reduction to your bills and carbon footprint. In terms of roof space, you will need approximately 9m2 per KWp.
What maintenance and cleaning do the systems need?
Solar photovoltaic systems are silent in operation, have no moving parts and require little maintenance. Simply cleaning and checking the panels annually is all that is required. During the lifetime of the system, you may in later years need to replace the inverter at a cost of approximately £500 – £1000.
What is the cost of a solar PV system?
Generally home owners will install a Solar PV system which is 2 to 4 KWp. Typically supply and installation will cost between £5000.00 and £8500.00. The cost of installation will vary according to ease of access to where the panels are to be mounted and the size of the solar PV system.
What happens if there is a power cut?
Our photovoltaic systems are entirely grid connected. If there is a power cut your system is automatically switched off. This is a safety measure designed to stop electricity leaking on to the national grid to protect individuals who may be working to restore the power supply.
What are the lifetimes of PV products?
All Solar Panels sold in the UK come with a 25 year 80% efficiency performance warranty. The mounting systems generally have a 10 year product warranty and the inverters a 5 year product warranty. The great thing about Solar PV is that there are no moving parts and therefore it is expected a system lifetime to be way beyond 30 years.
What about payback?
We are often asked, “What is the payback period?” for solar panels. Firstly, Solar PV does offer a payback which is great when compared to other systems in the home. For example central heating uses gas, requires maintenance and replacement at regular intervals and does not offer any kind of financial benefit whilst supplying heat and hot water.
In installing a Solar PV system we would expect that the total financial benefit which comprises of the Feed in Tariff, Export Tariff and savings on bills would mean the the initial outlay is covered in 6-8 years depending on the system size. From that point onwards there is a period of 17 – 19 years where you will benefit from a tax free income which is all profit and linked to inflation through RPI.
Additionally it would be expected that a system would put value on your property or make the property more saleable. The Institute of Chartered Surveyors say that having solar PV on a property will on average add 8.6% to the value of a property. This is obviously dependant on market conditions.
How much electricity will I generate?
This depends on the size of the system, the orientation and pitch of the solar panels and whether there is any shading issues. We always provide you with a conservative prediction of the system performance to a SAP (Standard Assessment Procedure) calculation at the design stage.
How efficient are solar panels?
Solar panels used in the UK must be accredited by the MCS (Microgeneration Certificate Scheme) and as such have been tested in a laboratory to prove that they will perform as the manufacturer says. Panels are performance guaranteed to work at 80% efficiency after 25 years in use.
How do Solar Photovoltaic’s work?
Daylight hits the solar panels and is converted to clean electricity by the photovoltaic cells, which is fed to the inverter. The inverter then converts the electricity from DC (direct current) to AC (alternating current) for use in the home. When the solar panels are producing more electricity than is needed, the excess is exported to the grid. At night, power is imported from the grid in the normal way. All this happens automatically with no customer intervention.
How can the energy benefits of the PV cells be maximised?
Orientation, shading and the temperature of the PV elements all impact on their output and must be considered at the design stage. The best orientation for solar PV in the UK is south facing at an angle of 30 – 40° from horizontal. Of course, the more energy efficient the building, the greater the overall benefit of the PV cells. It is also recommended to use as much electricity during the day as possible so it is better to run washing machines and other appliances when there is daylight to further improve the benefit.
How are PV cells affected by soiling?
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 tilt of the panel is at least 15 degrees. In extreme cases dust may cause a power reduction of about 10%. Simply cleaning the panels on an annual basis as you would a window will keep them performing well.
Does the system need batteries?
No, the solar PV systems Solarlex install are connected to the national grid. During the night when the panels are not generating, electricity is purchased from your utility company in the normal way. Any excess electricity generated during the day, for example when you are at work or on holiday is sold back to your energy supplier.
Does it really work in the UK?
Yes. Solar panels only require daylight to work, not direct sun and will even generate electricity on cloudy days. The UK has similar irradiance levels to Germany where PV has proved extremely popular over the last decade due to the Feed in Tariff being introduced there in 1999. The UK climate is perfect for Solar PV as we have plenty of daylight and a relatively cool climate. Solar panels lose efficiency in high temperatures.
Do I require planning permission?
Generally not. Most domestic installations are covered by Permitted Development Rights which means that you can simply go ahead without the requirement to apply for planning. However if the building is listed or within a conservation area, planning permission is required but will generally be looked upon favourably. Properties other than dwellings are not covered by Permitted Development Rights and advice should be sought regarding planning.
The planing portal serves to provide information on planning issues and can be found at: http://www.planningportal.gov.uk/england/public/buildingwork/projects/workcommonsolar6apr/
Can I sell the electricity I make?
Yes, our PV systems are grid connected. On top of the Generation Tariff (or Feed in Tariff as it is often called) you are paid for the excess electricity you produce. Your electricity supplier will pay a minimum of 3p per KWh that you export back to the grid. Some energy suppliers are paying higher rates for exported electricity.