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Solar Photovoltaic - Technical Details

How it works
Solar photovoltaic systems convert sunlight into electricity. They do this using silicon cells that create electricity when exposed to sunlight. The silicon cells are supplied in modules [link to Solar PV Modules Page] of various sizes, housed in alloy frames with toughened glass covers.

These modules are then connected together, in a similar way to connecting a series of batteries. The modules produce direct current which is then converted by an inverter into alternating current which matches the electricity supply in the building.

In the UK, the best performance comes from solar PV systems that are facing south. It is possible to mount them east or west facing, but these systems will produce about 20% less energy compare to south facing ones.

System size
This is generally dictated by one of 3 factors: demand matching, available space, and budget. Where space and budget allow, it is good to be able to match the demand of a property. System size is given as the kilowatt peak (kWp) value which is the maximum output under ideal conditions. Typically domestic systems range from 1kWp - 5 kWp.

Each kWp of installed capacity will produce between 750 - 850 kilowatt hours (kWh or units as they are referred to on your electricity bill) annually and will take up about 7 to 8 square metres of space. The average UK household consumes about 4,000 kWh annually.

Mounting method
PV systems can be mounted over the roof on a proprietary frame system or they can be integrated into the roof to form part of the watertight roof covering. Roof integrated systems are generally more expensive but have a lower profile and can be a better solution where the building’s aesthetics are important. The modules can also be mounted on gable ends, flat roofs or on the ground using a variety of frame solutions. It is possible to have slates or tiles that are themselves solar PV modules

Grid or battery
If a property is grid connected, it is cheaper to connect directly to the national grid. Any excess electricity is diverted automatically out into the grid and any deficit can be drawn from it. This approach avoids the need for batteries, which have a limited life and create a maintenance burden.

If no grid connection is available, the solar modules can be connected to a battery system, which can in turn provide electricity to the building’s appliances.


Roof Integrated	Over-Roof Mounted	Ground Mounted	Flat Roof Mounted

See our photo gallery for more examples.

Please do not hesitate to call us on 01981 241 399, if you have a specific product or project in mind. Alternatively, please complete and return the Solar PV Self SurveyForm.