The size of solar PV system you need depends upon several factors, such as how much electricity you use, how much sunlight is available at your location, the size of your roof and how much you’re willing to invest. After talking through your exact requirements with one of our environmental technology surveyors, they can recommend the best solution for your property.
Q: Do I need planning permission for a solar PV installation?
A: Recent changes to planning laws mean that a PV system on a domestic dwelling usually counts as 'permitted development' and can be installed on a sloping roof without the need for planning permission, as long as the panels project no more than 200mm from the roof surface.
If your installation is on a non-residential property, a flat roof or if your property is a flat, listed building or located in a conservation area or World Heritage site, you will require listed building consent or planning consent.
Q: How long do the systems take to install?
A: Our installations typically take two or three days to install. We can usually fit your installation within two to four weeks of receiving your signed quotation acceptance.
Q: Do the installers need any special access around my property for scaffolding or cherry-pickers?
A: For most installations scaffolding will be required. This is to protect our workmen whilst working on the roof and to comply with health and safety legislation. In the case of 'new build' installations scaffolding is usually already in place.
Q: Are the installers fully insured to undertake work on my property?
A: Yes all of our installers are fully trained and insured to undertake work upon your property.
Q: How can I tell if my roof is strong enough to take the extra weight?
A: Most roof structures are designed to take the increase in weight from solar PV panels due to over-engineering and original snow loading factors. Our system designer will check the existing structure and construction of the roof and discuss with you if any additional survey is required.
Q: Can the panels only be installed on a pitched roof?
A: No. Horizontal or vertical installations will also work, although the output from the system will not be as great as the optimum 30 or 45 degrees.
Q: Will they generate any energy in the winter months? Do solar PV panels generate energy when it’s not sunny?
A: Yes. Solar panel suppliers have enhanced the efficiency of solar power systems to the extent that it is now a very viable option even in cloudier climates. The important thing to bear in mind is that solar power depends on intensity of light, not necessarily direct sunlight. So even when it’s overcast your solar PV panels will still be producing clean electricity, to help power your home.
Q: How does shade affect my energy production?
A: Shading is critical. Minor shading can result in a loss of energy. This is because the cell with the lowest illumination determines the operating current of the series string in which it is connected.
This is one of the areas covered in the survey carried out before any installation. We use modern arrays that can bypass the affected cells to minimise shade effects; but these effects must still be considered.
If shading is unavoidable, or poor light is expected on a regular basis, then we will modify our designs and possibly even the type of cell we use. This can obviously only be taken on a case by case scenario.
Q: Do I need to clean my panels periodically?
A: Due to the use of self-cleaning glass and the system being installed on a pitched roof most of the time the rain will keep the modules clean by washing away any accumulation of dirt.
Shallow pitched roofs and horizontal installation will lead to a build-up of dust and debris, but the modules can be cleaned with either a hose or, if possible, soapy water and a nonabrasive brush.
Q: What converts the sunlight into electricity that I can use in my house?
A: Sunlight hits the photovoltaic cells and is converted to clean electricity. The inverter converts the electricity from direct to alternating current, for use in the home. When the solar energy system is producing more power than is needed it is exported to the grid. At night, power is imported from the grid in the normal way
Q: How does the Feed-in Tariffs (FITs) scheme work?
A: The Feed-in Tariff (FIT) scheme is a pay as you generate grant, designed to pay you for every unit of electricity (kilowatt hour) you generate, from a renewable source, such as a solar PV system.
Q: The FITs tariff is currently 43.3p; will this change over the 25 years?
A: Once you sign up to generate your own energy, you lock in to the Feed-in tariff of 43.3p (index linked) for 25 years. So for the next 25 years - you will get paid 43.3p for every kWh you generate.
Q: If I am not in the property, what happens to the energy my system produces?
A: Whenever your panels are producing more electricity than your home is using, it will flow back into the grid for other homes to use. You’ll be paid for this power so you can be sure your energy bills will be even less and none of your clean, green electricity will be wasted. This setup eliminates the need for batteries.
Q: Can the energy I produce be stored in any way?
A: No, the system is connected to the national grid. During the night, when the cells are not generating energy, electricity is bought from the utility company in the normal way. Any excess electricity generated during the day, for example when you are at work, is sold back to the utility company.
Q: What happens after the 25 years?
A: A well-designed and maintained PV system will operate for more than 25 years. The PV module, with no moving parts, has an expected lifetime exceeding 30 years. It is estimated that performance will decrease by less than 1% per year, which would mean that in 50 years they would still be 60% efficient.
