Solar panels or photovoltaic collect the sun's rays and generates DC electricity. An inverter changes the DC power into 240V alternation current (AC) suitable for use in your home, whilst a generation meter measures your electricity for production. During the night the panels will not produce any electricity so all electricity will be bought from the grid as normal. During the day a system of 2kw + could provide a typical house with most of its electricity during daylight hours, especially during the summer months.
Every unit of electricity produced will earn the system owner 13.39p in feed-in payments regardless of whether of they use it in their home or not.
A photovoltaic system can be fitted “off grid” which is a building not connected to the national electricity grid. In these circumstances the panels are connected to a battery to enable power recall during non productive times.