Technology

Solar PV Technology FAQs

Q. What is Photovoltaic (PV)?

Solar PV is electricity produced from an endlessly renewable and plentiful resource- the sun. Sunlight is converted to electricity by photovoltaic (PV) cells, which are usually made of silicon. Solar PV systems require almost no maintenance, produce virtually no pollution or greenhouse gases, operate silently and generate electricity during daylight hours, even on a cloudy day.

Q. How much space on my roof do I need for a solar PV installation?

Our grid connected systems start from around 1kWp power. This occupies about 8 square metres on your roof.

Q. How are the solar panels fixed to the roof?

For a standard roof we use rigid stainless steel brackets that are fixed directly to your roof rafters. The brackets hook out from underneath your existing tiles. We do not drill tiles/slates or use mastic/silicone to weather proof your roof. These techniques do not have a long life span but are frequently used by our lower quality competitors. If in doubt, please ask.

Q. How much electricity does a solar PV system generate?

For every kWp power installed on a South facing roof the system will generate around 800 kWh. This reduces by around 20% for an East or West facing roof and also depends on the pitch of the roof. We will discuss the expected output with you on a case-by-case basis.

Q. What does the inverter do?

The solar PV panels generate direct current (DC). This is not directly compatible with the 240V alternating current (AC) that is used in your property. The inverter converts the DC power to AC power that can be used in your property.

Q. How does the electricity I generate get in to my wall sockets?

Our fully qualified electrician will connect the system to your fuse board (consumer unit). The electricity will automatically flow from there to wherever it is needed.

Q. Do installations need batteries?

No, a grid connected system does not need batteries. Batteries add greatly to the cost of an installation and also significantly reduce the overall efficiency (typically by 20-30%). They are also toxic and have a relatively short lifetime.

Q. Do PV systems work well in the UK?

Solar PV systems work very effectively in the UK, though the annual output is obviously lower than in sunnier countries. That they provide a viable means of electricity generation in the UK is demonstrated by ongoing government support and from the thousands of systems that have already been installed.

Q. What happens if the system generates more than the building is using?

When the solar PV system is generating more electricity than the load demand in the building, all excess is exported to the grid. Export occurs automatically and can be measured (and income collected) using an "export meter".

Q. How is the solar electricity used?

The output from a grid connected solar system is fed directly into the existing circuits in the building, usually by a connection at the main distribution board. The inverter ensures your solar generated electricity exactly matches the electricity from the grid. Your surplus electricity which is not being used in your building is automatically sold to your energy supplier.

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Solar panels installed on a domestic roofSolar panel hangerPreparing solar panelling for useA PV panel fitter on the roofTesting solar panels before fitting
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