Photovoltaic Cell Technical Details
How does the cell work?
A photovoltaic cell consists of two types of silicon P-Type and N-Type. The surface of the cell is transparent so the light can pass through and fall onto the first layer of silicon. This layer of silicon has been manufactured to be positively charged. Likewise the other layer of silicon is made to be negatively charged.
When sunlight falls onto the cell a flow of electrons is created through the cell causing an electric current. This current can then be harvested and either used straight away, stored or exported.
Components
The main components of a solar photovoltaic system are:
1. Solar photovoltaic modules
- Converts sunlight to electricity
- 16% – 18% efficient
- Fix to pitched or flat roofs
- 1m2 generates roughly 100 kWh’s / year
- Very low maintenance – no moving parts
- Useful lifetime – 20 to 25 years
2. Inverter
- Converts DC (direct current) electricity produced by solar photovoltaic panels into 230V50Hz AC (alternating current) electricity used in domestic appliances
- Used in Stand Alone (off-grid battery systems) and grid-connected systems
- Comes as part of system package
3. Production meter
- Records units of electricity (kWh’s) generated by solar PV modules
- Comes as part of system package
- Homeowners responsibility
- Separate from Import-export meter - This records units of electricity imported from and exported to the national electricity grid. Most homeowners do not have this facility and it is the responsibility of utilities, not homeowners.
4. Electricity grid
- Acts as giant energy storage system, eliminating the need for battery storage
- Enables export of surplus electricity generated by the PV system
- Enables electricity power to be imported when demand exceeds supply
- Enables micro-generators to sell power to utilities through Feed-in-Tariff
- Grid connection reduces system costs and management
