What is a Photovoltaic System?
A photovoltaic system refers to the entire system of photovoltaic devices and supporting equipment required to generate electricity from light. A complete system may include some or all of the following: a photovoltaic array, an inverter, mounting, cabling, a solar tracker, and a battery.
Key Takeaways:
- A photovoltaic system is the collection of all the devices and supporting hardware required to generate electrical power from light.
- Photovoltaic array and photovoltaic system are often mistakenly used interchangeably.
- Photovoltaic systems can range in size from small rooftop systems to utility-scale installations.
Understanding Photovoltaic Systems
A photovoltaic system refers to the entire system of photovoltaic devices and supporting equipment required to generate electricity from light. A complete system may include some or all of the following: a photovoltaic array, an inverter, mounting, cabling, a solar tracker, and a battery.
The terms photovoltaic, or solar, array and photovoltaic system are often incorrectly used interchangeably. A photovoltaic array refers specifically to the collection of one or more photovoltaic modules that are wired together, while a photovoltaic system refers to the entire set of devices that are required to collect, generate, and distribute electricity for a home or business.
A typical 150 watt solar module is about a square meter in size which can be expected to produce around 0.75 kilowatt-hour (kWh) every day when averaged across most latitudes. This loss in apparent efficiency is due to how solar cells are constructed. Photovoltaic modules can produce electricity from a wide range of sunlight, but not all light wavelengths are used for generating electricity. Some wavelengths are lost due to heat and wasted by modern solar modules.
Since a single photovoltaic module rarely can produce enough electricity to power an entire home, a photovoltaic system often will have a number of modules that are connected together into a solar array to generate a larger amount of electricity. This array is then connected to a solar inverter in order to transform the direct current power produced by the modules into alternating current power that can be used by most household appliances.
Also included in a complete PV system is a number of mounting, cabling, solar trackers, and other electrical devices that help to optimize the power transmission from the inverter to a battery or storage device until the power is needed.
Collectively, all the accessories that do not include the solar array are referred to as the balance of system, or BOS, for shorthand. The balance of system also has the important task of balancing the power generating system with the power-consuming household or utility grid. This equipment must be carefully selected to optimize output, energy storage, reduce power loss during power transmission, and conversion from direct current to alternating current.
Photovoltaic systems can range in size from small, rooftop or building mounted systems to large utility-scale installations that generate hundreds of megawatts. Most residential systems are able to generate enough annual solar savings to recoup the cost of installation within 1-2 years.
Related Terms
Photovoltaic – the generation of electrical energy through exposure to the sun which excites an electron to a higher-energy state.
Solar Panel – The colloquial term for a photovoltaic module that uses sunlight to harness solar energy.
Inverter – Or power inverter, is a device which converts direct current energy to alternating current energy so that it can be used by typical household appliances.