Have you ever wondered how solar panels work? Solar energy can be a complex topic. However, after you break it down into simple steps it gets easier.
Here’s the basic science behind solar panels, so you can get an idea of how iconic Aussie sunlight can power your home.
How do solar panels work?
Basically, solar panels convert sunlight into electricity in four simple steps.
1. Photons Hit The Solar Cell, Exciting the Electrons
Solar cells consist of a positive and a negative film of silicon placed under a thin slice of glass, also called a PN (Positive/ Negative) junction.
A solar cell is essentially a PN junction with a large surface area.
Sunshine, both heat and light energy, comes from a nuclear fusion process occurring inside the core of the Sun. When you see a ray of sunlight, you’re actually looking at a stream of photons.
When photons hit the solar panel, little electrons inside the Positive/Negative (PN) Junction, (usually made of silicone, a popular semiconductor) are knocked loose. This creates both a free atom, and a hole where the atom should be. The hole is attracted to the P side of the PN Junction, and the electron is directed to the N side.
Solar panels have tiny metal fingers at both the N and the P sides of the junction. These fingers direct the holes to the P side and the electrons to the N side. They connect to an external electrical circuit, so that the flowing electrons generate electricity.
Then the process starts all over again for hundreds of tiny electrons. You see, that’s why solar energy is renewable – the only parts that move are the electrons and electron holes.
2. Direct Current Electricity is converted to Alternating Current Electricity
Now, this type of electricity created by the solar cells is Direct Current (DC). As the main electrical grid powers households and appliances with Alternating Current (AC) Electricity, it needs to be converted. This is where inverters come in.
The DC electricity produced by the PV cells does not have a waveform, it’s a direct line (hence its name, direct current). To become AC, it must become a sine wave.
Solar inverters reference the grid voltage and manipulate the DC voltage to imitate the grid’s AC sine wave. Essentially it converts the straight line current of DC to the wavy AC needed to power your home.
Once the solar inverter has transformed DC to the correct amounts of current, voltage and frequency that your AC appliances need to operate, this AC electricity can then be fed into your switchboard.
3. Solar Cells Work Together to Generate Enough Electricity
An individual solar cell working on its own only produces a very small amount of electricity. To make your solar panels work to produce enough electricity to run your appliances, these cells are connected together.
For one solar panel, the standard configuration used to be around 60 cells, at 4 watts each. Making a solar panel that produces 240W of power (60 x 4W). These days, however, they’re finding better materials to make the cells which can create much more power.
In fact, Hyundai’s new shingled cell module technology generates 390Watts of power per panel. They do this by laser cutting the cell into five strips, then overlapping the cells with electrically conductive adhesive.
This solar cell arrangement optimises the performance, increasing the output by reducing stress on the panels as the temperature changes. It also better utilises space to provide almost 100% coverage.
4. Solar System Owners Sell Excess Electricity
When you install a solar power system, you may find it is producing more electricity than required.
If you don’t have a solar battery to store the excess energy, you can sell it to your energy retailer.
Excess power fed back into the grid is measured by your electrical meter in your switchboard.
The rate you get for selling this electricity back to your energy retailer is called a solar feed-in tariff. These rates were once at around 17c/kWh. However, due to changes in government regulations, energy retailers are now dropping these tariffs to as low as 5c/kWh.
This doesn’t mean that you won’t make money off selling your excess energy. But, we do suggest to our customers that setting timers to use electricity during sunlight hours could be more cost-effective.
If you’d like to know more about how solar panels work, or the best feed-in tariffs on the market, say g’day.