Solar PV - how it works?

pvhow2The diagram shows the components that comprise a typical domestic system. The main components are the module array, an inverter and the balance of system components such as a generation meter, isolators (switches) and cables.

Panel Array - Most solar panels are made from silicon – the same semiconductor material that computer chips are made from. Sand is distilled to purify it and with the addition of compounds that conduct electricity, the cells generate electricity when exposed to light. Although output is highest in clear sun light, they generate even on overcast and cloudy days.


silicon1Cells are wired together and encapsulated in weatherproof and robust materials to form panels – or modules as they are referred to in the industry. Modules generate DC electricity which must be converted to AC so it can be used in buildings and exported to the grid.

Inverter – The inverter does two main jobs. Firstly, it converts DC electricity to AC – the same type of electricity we use at home and work. Secondly, it manages the grid connection ensuring any surplus energy is automatically exported to the grid. Most inverters are designed to shut down if the grid fails but some can start generating from a set of batteries. Norfolk solar offer a full range of inverters to meet the needs of different projects.

The output of a PV system is measured in KiloWatts at peak output – or Kilowatt Peak (kWp). This is how much power the system is capable of producing in standard conditions that are similar to bright sunshine in the summer.

Most houses can support between 1 and 4 kWp on their roofs or on ground mounted systems. For businesses with large south(ish) facing roofs or space for ground mounted systems there is no practical limit. However for systems that are capable of exporting more than 16 Amps per phase (3.8 kW), permission must be sought from the local distribution network operator (DNO) to connect the generator. This application is known as the ‘G59’ process. Norfolk Solar offer a G59 management service to its customers as part of our standard service. Please call and ask for details.