Last week SEI's engineers formally handed over the new solar system at St Mary's Catholic First School in Dorchester. This completes first phase of the new extension to the schools facilities.

The PV system was part-funded by the Low Carbon Buildings Programme, and has been designed by SEI to allow for complex shading not just from existing buildings, but also the later phases of extension currently planned.

The system itself comprises 54 no. Sharp monocrystalline PV modules accompanied by Fronius inverters, which are manufactured in the UK with a minimal amount of embedded carbon. The layout was chosen after several design iterations to minimise shading effects on the annual yield, including for surrounding buildings, obstructions on the roof, and even a "tower" expected to be built in the coming years. Since PV is very sensitive to shading - even the shadow of a railing can have a drastic effect - it is imperative that future developments are acounted for, whether they are new constructions, tree growth or other predictable changes.

Furthermore, in order to make the array form an aesthetically pleasing shape, two "dummy" modules were included; these are modules from the same production line as the generating modules, but that failed the manufacturer's stringent quality tests. In this way, SEI's design team was able to optimise cost, generating efficiency and aesthetics, without the usual compromises.

Following completion, our client, Dorset County Council, passed on some praise:

"The school have been very impressed by SEI's handling of the project and the M&E engineers, Worldwise, particularly wanted to thank you for your input in the early design stage when you assisted them and the architects to come up with the correct PV solution for the building"

Now fully operational, the system should generate some 6,200 kWh every year (equivalent to 1-2 typical homes), offsetting the emission of 3.5 tonnes CO2 annually. For technical information and more images, please click here for SEI's project summary.