How solar PV works
The sun is incredibly powerful source of energy. In this post we take a look at how solar PV works.
How solar photovoltaic cells work
Solar cells contain silicon, a semiconductor, which absorb light and converts solar energy into electrons. The electrons flow through the semiconductor as electrical current. The current flows through conducting strips – the grid-like lines on a solar cell – and is combined with the power from the other solar cells in a solar module.
A solar cells efficiency at converting sunlight into electricity depends on the semiconductor. To boost energy yield, researchers and manufacturers are looking at different materials and bifacial solar cells, which are double-sided to capture light on both sides of a silicon solar module; from the sun above and light reflected off the ground or roof where the panels are installed.
How solar photovoltaic panels work
Solar photovoltaic panels are made up of several solar cells. A typical solar panel is made up of 60 or more individual solar cells. The solar cells are covered by tempered glass to protect them as they are fragile and are wired together in series. This means that each solar cell raises the output voltage of the panel. A typical solar cell produces about 0.46 volts of direct current (DC) so a panel with 60 cells would produce 27.60 volts DC. The solar cells are stuck to a backing membrane and the layers of the panel are sandwiched together and kept rigid by an aluminum frame. The current produced by the solar cells is fed through to a junction box on the back of the solar panel which has output cables to enable panels to be wired together. Solar PV panels are also known as ‘solar modules’.
Solar power conversion
Solar panels produce direct current (DC) – the same as a battery, just much more powerful. In order to use the power and export it to the power grid it has to be converted to alternating current (AC) by an inverter.
Solar power inverters come in several different sizes. Micro-inverters are small units which convert the power from a single module, which can have advantages if parts of a solar array are shaded or broken because the lower power from these panels will not affect the entire array.
How a home solar PV system works
- Solar PV panels are installed on the roof and capture energy from daylight, creating DC electricity.
- The DC electricity is converted to AC by an inverter, usually situated in the loft.
- The inverter is wired into the home’s fuse board, providing free electricity during daylight hours. At night electricity is imported from the National Grid.
The Solar Feed-in Tariff was introduced to help people make money from having solar PV installed.
Getting solar PV installed on your home
PV installation is a simple process, which usually takes less than one day. There is no change to your wiring and electricity will always be available, just like before, but you will not pay a penny for the electricity you use during the day! At night you will still need to ‘import’ energy from the grid, like normal. Any ‘excess’ units you generate during the day will be ‘exported’ to the grid.
Solar photovolataic systems are extremely reliable, since they do not contain any moving parts, and the panels themselves are guaranteed for at least 20 years. See our guide to the differences between Polycrystalline vs monocrystalline and other types of solar photovoltaics.
If you are thinking of getting solar photovoltaics installed be sure to use a Mircogeneration Certification Scheme approved installer.