Your questions on photovoltaics

Select a category to view some frequently asked questions or if you have a new question please get in contact.  

How many panels will I need to give a 100kWp output and what roof area will the array require?

You would need 322 panels with 310Wp capacity rating, all orientated at due south. This number of panels would require 966m of flat roof without any areas of shading. We can produce calculations and an array layout for you if you need assistance. Call our technical team on 01473 257671 for more information.


To meet BREEAM and planning requirements both a green roof and PV need to be specified. I can't compromise on the roof area for the green roof as the full space needs to be vegetated. How can I deliver both?

We have a solution that combines the technologies enabling both to be installed without one compromising the other.  Bauder BioSOLAR is an integrated solution where the anchor board for the PV mounting rails is ballasted by the substrate and vegetation of the extensive/biodiverse green roof.  The PV modules are raised above the vegetation so that there is ample growing room for the plants so that they don't shade the modules and light and moisture can reach beneath the panel to support the plants. 
More about BioSOLAR ►


How is your PV system attached to the flat roof? A different supplier is planning on mechanically fixing the rails through the waterproofing and into the deck, but I'm unsure that this method will ensure the waterproofing is intact?

A distinctive element of our solar system for flat roofs is that the installation doesn't require any penetrations of the waterproofing or roof deck, even in a non-ballasted arrangement. Our system utilises membrane-to-membrane fixing techniques to secure the mounting units to the roof. The weld areas create a very stable base for the units and PV modules, even in areas at risk of high wind uplift.  
More on our BauderSOLAR system and images of installation method ►

Where should the photovoltaic panels be sited?

The ideal siting for a PV array on a flat roof is with a due south orientation, on an area without possible shading from overhanging trees, other buildings or lamp posts etc.


I have trees near my roof, will your photovoltaic system still work if some of the panels are occasionally in shade?

When modules are in shade their performance can be affected. If you install a power optimiser each individual module is monitored to determine the maximum power point (MPP) so that any shading does not impact on the entire string. This monitoring system can give up to 25% more output from an array.  
More on power optimisation ►


Can I retrofit a PV array on my building's flat roof?

Yes, as long as the additional weight loadings can be accepted by the building's structure. An important factor is to ensure that the life expectancy of the waterproofing system currently on or to be installed on the roof will match that of the PV array, otherwise you may find that the waterproofing system will need replacing earlier resulting in the complete removal of the array before works can commence to reinstate the integrity of the roof. The ideal time to add photovoltaics is to do it at the same time as refurbishing the waterproofing system. 
More on retrofitting PV ►