The solar photovoltaic cells in photovoltaic panels offer us the mechanism to capture sunlight and to convert it into useful electric energy. Photovoltaic cells have at two or more layers of semiconductors, such as silicone. One of these will be positively charged, and one negatively. The photo part refers to light or sunlight in this context and voltaic relates to the production of electricity. Therefore photovoltaic electricity is the electric energy we get from sunlight.  When sunlight reaches the semiconductor in a cell, the electric field where these opposing layers meet causes electricity to flow.

The greater the intensity of the light that falls on the cell, the greater the flow of electricity. During the course of the day, the amount of light received from the sun will vary. Radiation will typically start out small, gradually increase until noon when it peaks, and then it will slowly decrease during the rest of the afternoon.  There are many kinds of photovoltaic panels. More recently the market has started seeing PV tiles that fit onto any standard roof. The attraction of photovoltaic tiles is that they have a minimal visual impact, compared to other panel systems. The light on the solar PV panels is converted into clean electric energy, and there are no moving parts involved, making such an installation extremely durable and maintenance free.

The power you will draw from this photovoltaic solar panel system is initially Direct Current (DC). By adding an inverter, this DC current is switched to Alternating Current (AC) to seamlessly power your household appliances.  The solar electricity then reaches the mains via the fuse board. The amount of electricity generated with the photovoltaic cells system can be measured and recorded with a meter, and, depending on your relationship with the electricity supplier in your local area, any excess electricity can be sold back to them.  The amount of energy available from the sun varies depending on your location. It is calculated on the basis of the amount of available solar ratiation at noon, which gives you the daily average hours of maximum radiation.

Even in cloudy regions such as Scotland, where 800KW hours per square meter is the average, or London which receives 1000, such radiation is enough to power energy efficient homes. You would need only around 10m2 or less of photovoltaic panels to power such a home entirely from solar electricity. If you want to first calculate the number of photovoltaic panels you will need to get the desired amount of energy, or even to go completely off grid, there are solar calculators available specifically for this purpose. You should also consult some of the published research about your city or region to determine the expected amount of average daily solar radiation in your area.