How Does Solar Power Work?

That’s a great question. As you already know, solar power is created from the energy of the sun. That’s kinda obvious – and usually where the definition ends when I am teaching kids.

If you are looking into harnessing the sun’s energy for your home, before you decide how much solar power you need, you should be aware that there are 2 distinct types of solar power that are harvested in very different ways.

The 2 types of energy we harvest from the sun are its heat and its light – here’s briefly how they both work.

Solar Power Type #1 :Turning the sun’s light Into electricity

When we harvest its light, we are using a phenomenon called the photovoltaic effect to convert the light directly into electricity. When people ask the question “How is solar energy produced?” they usually want to know how the PV Effect works. Devices that use the PV effect to produce electricity from light are called Solar PV panels, or just simply solar panels.

A common misconception about how solar power works is that PV panels use heat to create electricity. In fact, heat is the enemy of electricity production in solar panels and high temperatures actually reduce their efficiency. Perfect conditions for solar energy harvesting from a PV panel are strong sunlight but low temperatures. The wattage rating of solar panels is determined under standard testing conditions of an ambient temperature of just 25C.

If you are interested in the details of how a PV system works then have a gander at this solar power system diagram.

Here are some typical solar PV panels installed on an Australian roof.

 Solar Power Type #2 :Turning the sun’s heat into … heat.

When we harvest the heat in the sun’s rays we are using it to heat up a third party gas or liquid. For example: solar hot water heating. This type is called “solar thermal energy”.

Here are some solar thermal panels surrounded by PV modules:

Just to add to your confusion, you can actually generate electricity from a solar thermal system. To do this you take the heat from that is generated and use it to boil water. When the water boils, you get steam and you can use this steam to drive a turbine that creates electricity as it spins. To get the turbine to work efficiently you need to get the steam, very, very hot (over 500°C for optimum efficiency). To attain these kind of temperatures, the sun’s rays need to be focused, or concentrated (like when you used to set fire to things with a magnifying glass as a kid). This type of electricity production is called Concentrated Solar Power (CSP) and is only used for very large commercial or utility-scale systems.

Creating the energy is only half the story. Because solar energy is only generated when the sun is shining, how you use the energy will determine how useful and valuable it is to your household. How and when you use it will determine how quickly your solar system pays for itself.

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