In this article, we aim to cover how solar panels convert heat from the sun into usable electricity. We dive into the science behind solar power and list a few important factors you should consider before investing in a solar system.
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How do solar panels work in Australia?
Solar panels work through a series of events that allow customers to take advantage of the sun’s rays. This process essentially takes place in five steps:
- Sunlight hits the solar panels on rooftops
- Solar cells are are activated and produce electrical currents
- Electrical energy is converted via a solar inverter
- Converted electricity can be used to power your home
- Excess electricity can be fed back into the grid for a small rebate off your energy bills
The science behind solar panels
Solar power works by utilising a chemistry phenomenon known as the ‘photovoltaic effect’. Essentially the photovoltaic effect describes a reaction where certain materials generate an electrical current when exposed to sunlight. Silicon is well known for these properties and that’s why it’s used in nearly all types of solar panels.
In contrast, traditional power generation systems rely on an energy source to spin a turbine, in turn charging a generator that creates an electrical current – prime examples are coal power plants, wind turbines and hydroelectricity plants.
Do we still have you on board? This video may help…
What do solar panels do?
Without going too deep in to the science behind the photovoltaic effect, essentially what happens is that when photons of light hit the n-type layer of silicon on top, it gives energy to an atom’s outermost electrons, allowing electrons to break away from their atomic orbits. The flow of these free electrons form a DC electric current. This DC current is then transformed by an inverter in to useable AC electricity. The loose electrons will eventually flow to the p-type silicon, while any excess electric current which your household does not use is fed back to the grid.
See the below diagram on how solar panels work:
What are solar panels made of?
Solar panels are comprised of an array of solar cells, which are the smaller blue or black squares within the panel. Solar cells in most commercial panels are usually made of two layers of silicon described as a p-type on the bottom and an n-type on top. These layers are sandwiched together by thin metal lines which serve as the solar cells conductor.
Of course, different brands might use slightly different materials or grades of silicon to make their solar panels more efficient than competing brands. The silicon can also take completely different structures; Black solar panels are said to be ‘monocrystalline’ which have higher efficiency ratings due to its uniform structure. Blue solar panels are known as ‘polycrystalline’ meaning they have multiple silicon structures which in turn makes them slightly less efficient, however generally more affordable.
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3 things to consider before installing solar
The sun provides what is essentially a limitless source of green energy, yet solar power still has its pros and cons. Here are three factors to consider before investing in solar:
1. Solar panel efficiency
Solar panels are much less efficient than traditional power sources. To illustrate, a coal power plant can convert around 70 per cent of the energy contained in coal into useable energy. By contrast, the world record for solar cell efficiency is 46 per cent, with real-world efficiency usually being a lot less (around 10 to 25 per cent) due to cheaper construction of commercial panels. This low efficiency means we have to use a lot more solar panels to produce enough electricity, holding solar power back from its full potential as an alternative energy source.
Solar panels need sunlight (duh), meaning that the climate and weather has a massive impact on the output of your solar panels. While here in Australia most of us enjoy a warm and sunny climate, many parts of the world are not so lucky. Cloudy countries will not be able to produce nearly enough solar energy for it to serve as a reliable energy source.
Solar panels unfortunately remain quite expensive, costing anywhere between $2,500 and $12,000, depending on the size. To put that into perspective, a relatively standard 4kW solar system will cost you around $5,000, excluding installation costs. The silver lining is that the price of solar has come done considerably in recent years, and is expected to keep falling.
While solar technology definitely has a long way to go, it is a fantastic alternative source of energy with limitless potential. We hope this article has given you a better understanding of the workings and practical benefits and challenges of solar power.