The PV cells generate electricity when exposed to photons of sunlight. PV Solar panels do not need to be in direct sunlight, daylight will produce solar energy, this works exponentially; the more sunlight exposure, the more solar energy produced.
Therefore, PV solar panels are most efficient when tilted in a southerly direction. Semiconducting materials, such as silicon, are able to undergo a process known as the ‘photovoltaic effect’.
What this means is that when they absorb photons of light it causes them to produce electrons. The electrons produced are then captured as a DC current and are converted into an AC by an inverter. This current is then either used straight away by the home or it can be sent to the national power grid for energy suppliers to use.
A PV generation meter can be placed in the home or workplace so there is a visible real-time monitor of the amount of electricity the system is generating. If the system is set up to send electricity to the grid, then the meter will also monitor this.
The cheapest, but least efficient type of solar power derives from the technology that powers solar power calculators or watches.
This type of Solar PV is known as amorphous or ‘thin-film’ silicon, as a basic explanation it is a thin layer of silicon coating a material such as glass. This technology is cheaper than others but to get a good return a large surface area is required as its efficiency is low.
The thin-film silicon technology is not very popular in the UK. It is the same type of technology used to create solar roof tiles, which can be used to either cover a whole roof or part of a roof. Being thin-film though solar roof tiles are not very efficient compared to other types of PV solar.
Widely available in the UK and a popular choice for PV solar power is polycrystalline. This is made up of many small crystals of silicon that are cut from a wafer. It is relatively efficient and cheaper than monocrystalline making it a popular option for photovoltaic solar panels.
Monocrystalline solar panels are made up from a single silicon crystal, so they are purer than the previous two. This type of PV solar panel is the most efficient mentioned so far but tends to be the highest in cost.
Hybrid solar panels, or their official name ‘heterojunction incorporating thin-film’ (HIT) are produced from a monocrystalline cell covered with a thin-film. By having the two materials working together it can create greater energy conversion efficiency.
This is seen as a premium option for solar panels and is the most expensive technology.