What is photovoltaic solar power?
4.5 minutes | 16 Dec 2021
The job of solar photovoltaics (PV) is to harness sunlight to generate electricity. In order to do this, solar photovoltaic devices, called cells, are used, which are contained within solar panels, also called photovoltaic panels, or modules.
Understanding photovoltaic systems involves knowing the basics.
“Photovoltaic” comes from two words: photons – the process of converting light to electricity – and voltage. Solar cell technology as we know it today has actually been around since the 1950s, when scientists created a practical, working solar cell made from silicon. Costs prevented mass commercialisation of the technology at first, but prices fell as cells gradually became more efficient at converting sunlight to electricity.
The solar PV module
Solar cells are strung together, forming a photovoltaic module. You’ve no doubt seen the grids on PV solar panels. Those are the individual cells within the module. The modules, or PV panels, are then connected to create the solar system.
Cells are small and capable of producing around 1 or 2 watts of power each. They’re incredibly thin – about the thickness of four human hairs. They contain a material capable of conducting electricity once the sunlight provides energy. This material is typically silicon and acts as a semiconductor. By “semi,” we mean the material conducts electricity more than an insulator, but less than a metal.
How PV power is created
Photovoltaic energy is created via these steps:
- The semiconductor absorbs light and transfers that energy to negatively charged particles, called electrons.
- The electrons flow through the semiconductor as electrical current – other cell layers extract the current from the semiconductor.
- The current flows through metal contacts – the grid-like lines on a solar cell – before it travels to an inverter.
- The inverter converts the direct current (DC) to an alternating current (AC).
- The AC travels into the electric grid or, depending on the system, connects to the building’s circuit.
You can learn more about inverters in our solar inverter guide. Also, get to know the other solar PV energy solutions you’ll need in Types of solar equipment, explained.
How photovoltaic technology is made possible
In order to consistently generate photovoltaic solar energy year after year, photovoltaic solar panels have to withstand the outdoors. The ability to perform depends a lot on the photovoltaic materials, which must be durable and robust. We’ve already mentioned that the cells of a solar photovoltaic module consist of a silicon semiconductor. This semiconductor is enclosed by a protective material in a metal frame. The protective material is an encapsulant which consists of transparent silicon or a butyryl plastic and bonded around the cells. The cells are then embedded in ethylene vinyl acetate (EVA).
A polyester film – mylar is one example – is used for the backing. A glass cover or sometimes lightweight plastic encases the array, while the frame is steel or aluminium. Silicon bonds everything together. The bulk of the electronic parts are usually made from copper.
Solar cell to solar array
A solar cell module array is part of a photovoltaic solar panel system. What is an array in solar PV systems? It’s a collection of solar photovoltaic PV panels. The panels are wired together to form one large-scale solar energy photovoltaic PV system. A solar PV array is usually associated with solar farms, but really, it’s any grouping of connected modules.
Photovoltaic panel power output
Solar photovoltaic conversion of sunlight into usable solar energy is typically 20%. This means the photovoltaic panel output can, in theory, exceed 400 watts of power. The more efficient the panel is at converting sunlight into energy, the higher the output.
Most solar panels with 60 cells generate between 270 and 300 watts. Let’s say your panels will be in direct sunlight for five hours a day. Now let’s use an example wattage from one solar panel with 60 cells at 290 watts of power. The calculation for estimating your energy output would be:
5 hours x 290 watts = 1,450 watts-hours, or 1.5 kilowatt-hours (kwh)
This translates to around 500—550 kWh of energy a year for each of your panels.
Applications of photovoltaic systems
Photovoltaic power is used for a variety of applications, either as a way to reduce one’s carbon footprint, save energy costs or because an area is not served by power lines. Examples of how and where solar photovoltaic energy conversion systems are used include:
- Space satellites
- Water pumps
- Parks in remote regions
- Remote residences
- Telecommunication repeater stations
- Navigational aids
- Home appliances
- Office equipment
- Laptop computers
- Supply of occasional power
- Calculators and watches
- Military uses, e.g., lightweight PV for charging electronic equipment in the field
No matter what your application is, you can also learn more from our Quick guide: components for your solar PV system.
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