Photovoltaics - solar electricity

Photovoltaic (PV) systems produce electricity by converting the suns rays into usable electrical energy. This electricity is typically connected to the mains supply in the building via an inverter to off-set your electrical consumption, (grid connected). Depending on your electricity supplier you will be paid an amount for the electricity you produce.

Your consumption occurs as you use electical appliances, for example, small amounts when you turn on a (low energy) light and large amounts when you put the kettle on. If your PV panels are generating enough power when you are using it then you'll be using their solar generated electricity. Any excess power demands, for example, after dark or when using a kettle, are drawn from the grid.

The PV system will usually supply a small (1kw to 2kw peak for a typical domestic system) but consistent amount while the sun is shining. The amount will be at its highest in the summer and at the lowest in the depths of winter.

Over the year the system could be sized to provide your annual need but most of the output would be in the summer. Electricity accounts for about 15%-20% of the total annual energy needed by a typical house (unless you have an electric heating system). However the proportion of carbon emissions is greater than this because only around 30% of the energy of the fuel burnt at a power station is delivered as electricity to your home, the rest is lost in generation and transmission.

PV systems are about £8,500 for atypical domestic installation but are easy to install have a long lifetime and require next to no maintenance. Greenshop Solar currently provide PV systems through their partners at Dulas Ltd.