Mr Holloway has high electricity usage and after some research concluded that with the clean energy cashbacks incentive (feed-in tariff) and a 120m² south facing roof, solar PV would be an ideal investment.

Following his research, Mr Holloway decided that he wanted to maximise his electricity generation for his roof whilst reducing his carbon footprint by selecting high efficiency SanyoHIP 215NKHE panels. The Sanyo HIP 215 are hybrid PV panels, they combine simultaneous conversion from high quality monocrystalline silicon and an amorphous silicon coating.  Amorphous silicon absorbs light towards the blue end of the spectrum better than crystalline silicon (whose blue colour betrays their weakness in this area).  This results in an unparalleled conversion efficiency of 17%.  These PV panels also work better in lowlight levels where blue light is more prominent.

Mr Holloway’s final decision was a system comprising of eighteen 215W Sanyo panels giving a total peak output of 3.87kW and an expected annual production of 3,226kWh saving 1,832kg CO2. He opted for an ‘in roof’ mounted solar PV system to save costs on conventional tiles and he believed it was more visually pleasing.

The Solar Photovoltaic Installation

Firstly, the roof covering for the surface area of the PV panels had to be removed. Then a roofing membrane was laid over the intended module field to ensure the area remains waterproof whilst the tiles are not present. A small sealing strip was then cut along the lower edge of the uncovered roof and fixed to avoid any leakages.

A foam filler is fitted to the sealing strip and corrugated metal sheets are then placed on to the roof and attached using sheet metal screws. Clamps are fitted to the metal sheets to support the weight of the solar PV panels on the roof, and to ensure that they run parallel and look as neat as possible.

The panels then slide into the clamps and can be tightened so they are securely fixed and no movement is permitted. As each PV panel is fitted, it is connected to the next PV panel in sequence via the electrical wiring underneath it. This is to ensure that the wires are not exposed to the outdoors, and also means that the system continues to look as tidy as possible.

Once all the solar PV panels were firmly in place, any previously removed tiles surrounding the array were replaced and any remaining gaps are sealed to prevent draughts and insects.

The Solar Photovoltaic electrical installation

Meanwhile indoors, the AC cabling was run up through the house by our qualified electrician into the attic via a route determined in advance with the client. Once in the attic, the cable was passed through an AC isolator and into the inverter, which in this case was an SB3800.

The DC cables were run between the inverter, through a DC isolator and then

down under the eaves where they could be connected to the solar PV panels.

Once everything was in place, the system was initialised and tested.

Solar Photovoltaic installation rewards – Earnings from feed-in-tariffs

EvoEnergy commissioned the system immediately after the installation was complete. Mr Holloway is now a registered producer of electricity and will be benefiting from the Feed in Tariffs, earning payments of 41.3p/kWh. This system will roughly earn Mr Holloway £1,074 per year, giving him an 8% return on his investment.