How solar panels work

Solar panels are becoming increasingly common due to their huge potential for clean energy production. Spain gets some 25,000 hours of sunshine a year on average, so not only can we use these devices to generate energy in a sustainable way thanks to the sun, but it is also a great opportunity to save and generate renewable energy at the same time.

But how does a solar panel work? How are they used to generate energy?

It's like this:

There are two types of panels: solar thermal collectors and solar photovoltaic panels. Let's look at what each of them does.

Solar thermal collectors

These are devices that make use of solar energy in a simple manner. Basically, they work through an accumulator which transfers heat to the water we want to heat. In some of these devices, the water is stored elsewhere, circulates and is heated as it passes through the collector. Solar thermal systems, on the other hand, heat the water in their own storage unit.

Photovoltaic solar panels

They consist of photovoltaic cells, which harness the sun's energy. The sunlight generates electricity, through the photovoltaic effect. How?

 Photons are particles of electromagnetic radiation which include, for example, gamma rays, X-rays, ultraviolet light, visible light or infrared light. The action of photons releases electrons, which as they move about generate positive and negative charges on nearby semiconductors, creating an electric field capable of creating an electric current.

Alexander Edmond Becquerel was the first person to study how the sun affected electromagnetism. Based on his research, the inventor Charles Fritts, used selenium, brass and gold as a conductor to create the first photovoltaic cell in 1833. It took 120 years to be perfected. Bell Laboratories introduced the first modern photovoltaic cell in 1954.

Early applications of photovoltaic cells were heavily constrained by the cost of production. However, they began to be used in the "space race": The US satellite Vanguard 1, launched in 1958, used them and was able to remain operational for over 7 years.

In the late 1960s and 1970s, due to the oil crisis, new investments improved these photovoltaic cells and made them cheaper to produce, with the aim of positioning them as an alternative energy source. Industrial production began and they were installed all over the world.

It was in Japan that a photovoltaic solar panel was first used commercially: in 1966, a 225 W panel was installed to supply the Ogami lighthouse with electrical power. This solar panel raised people's awareness about the commercial use of this sustainable energy.

In the mid-1970s, photovoltaic panels were used to supply energy to oil platforms, berths or buoys, and in the 1990s, they began to be a common sight all over the world.

What goes into a photovoltaic panel?

Solar panels are made up of several photovoltaic cells with a surface area of ​​about 10 square centimetres with a protective coating made of materials such as ethylene and vinyl acetate. These devices need to allow sunlight to pass through, but they are exposed to extreme conditions and very high temperatures.