History and functioning of solar panels

In recent years, solar energy has overtaken electrical energy. Ten years ago, solar panels were exclusively used by companies or households with a high domestic economy. Today, more and more people are opting for this type of lighting in their homes.

The use of renewable energies is a necessity if we want to meet the Sustainable Development Goals (SDGs) of the 2030 Agenda and reach zero emissions by 2050. All of this, with the aim of slowing down the advance of climate change and, as a consequence, the increase in the Earth’s global temperature.

According to Bloomerang New Energy Finance’s (BNFE) New Energy Outlook (NEO) 2018, the role of wind and solar energy is becoming increasingly important. “By 2050, wind and solar technologies will provide 48% of total electricity. While hydro, nuclear and other renewables will provide 23% of zero-emission electricity,” they explain.

But not only that, Spain ranks third among the main solar markets, behind Germany and the Netherlands, as reported by Solar Power Europe. Furthermore, despite the COVID-19 pandemic, 596 megawatts (MW) of photovoltaic capacity for self-consumption were installed in 2020, representing an increase of 30% compared to 2019.

Society is becoming increasingly aware of the importance of generating clean, green energy for our future and that of future generations. Solar lighting is within everyone’s reach, “people are increasingly opting for solar products to illuminate and decorate their exteriors,” says Javier Zorrilla, general manager of Arteconfort. According to figures compiled by the company, during 2020 they sold more than 330,000 solar products.

In this article we explain everything you need to know to get started in the world of solar energy.

In high school we were taught that one of the main characteristics of science is that it is collaborative, and the emergence of solar panels is an example of this. The first to appear on the scene was Edmund Becquerel, in 1839, with the discovery of the photovoltaic effect, while experimenting with a cell made of metal electrodes in a conductive solution. He realised that the cell produced more energy when exposed to sunlight.

Following him, in 1873, Willoughby discovered that selenium could function as a photoconductor. Three years later, William Grylls and Richad Evans applied the photovoltaic principle found by Becquerel to selenium. The two realised that the chemical element had the ability to generate electricity when exposed to light.

It was not until fifty years later that Charles Fritz created the first functional selenium solar cell. This would be the main precursor to today’s solar cells, as today’s solar panel cells are made of silicon. A breakthrough was developed at Bell Laboratories in 1954, where Daryl Chapin, Calvin Fuller and Gerald Pearson made a solar cell out of silicon.

The first practical use of this photovoltaic cell discovery was in the first two geostationary satellites of the Soviet Union (USSR) and the United States (US).

Turning to current affairs, the use of solar panels reached record levels in Europe this summer. For the first time, solar power generation averaged 10% in European Union (EU) countries in June and July, according to think tank Ember.

Before purchasing a solar product, it is advisable to know the types of solar panels that exist today in order to make a good choice. As mentioned above, today’s solar panels are made from silicon, the second most abundant element in the earth’s crust, which is mined. The transformation process of the mineral gives rise to monocrystalline and polycrystalline silicon.

To understand how solar panels work, the first thing to know is how they are made:

1. The key step is the collection of silicon from a mine and its subsequent purification.
2. Once the material is purified, it is melted in crucibles and ingots are obtained, which can be square, if we want polycrystalline silicon, or cylindrical, if we want monocrystalline silicon.
3. These ingots are cut into thin sheets to obtain the wafers, the substrate on which the various chemical processes are carried out until the cells are obtained.
4. Once we have the solar cell, characterised by being thinner than an eggshell, its assembly must be carried out by very specific machines that treat the material with the delicacy it requires.
5. Finally, we obtain the solar module, which is a set of cells assembled and connected to each other.

In this respect, monocrystalline panels are characterised by high energy efficiency with an efficiency of up to 24%. They are slower to manufacture and slightly more efficient. We can distinguish this type of panel by its black colour and bevelled corners. As it is a more expensive panel, it is generally intended for professional use.

Polycrystalline panels, on the other hand, are faster to heat up and are cheaper and quicker to manufacture, making them a type of panel intended for domestic use. It is characterised by its high efficiency, reaching 19% efficiency and is distinguished by its right-angled corners and blue colour.

Solar panels, in turn, are distinguished by the type of encapsulation and batteries.

The functioning of a solar panel often generates curiosity among the population, which is why we explain in a simplified way what it consists of. First, when the sun’s rays hit the plate, the solar cells are responsible for transforming the sunlight into electricity.

To do this, these cells are mixed with materials such as boron or phosphorus to form two parts: one with positive electrons and one with negative electrons. Once the cell is exposed to the sun, photons, particles that carry visible light, move the electrons from the area where there is an excess of negative charge to the part where there is a lack.

As the photons release electrons, more electricity is generated. Those electrons that have not been used are returned to the panel, resulting in a never-ending process.

Arteconfort solar products incorporate a polycrystalline or monocrystalline panel with a glass or PET encapsulation. These types of encapsulation are characterised by their high efficiency and the fact that they are an anti-corrosive material.

“We opt for these two types of encapsulation because they are the ones that offer greater durability over time. The use of one or the other depends on the type of lighting we want for a product”, explains Javier Zorilla. For example, glass encapsulation is used for more demanding lighting, as is the case with the PEGASO series of streetlights.

But how much can I save on my bill if I use solar luminaires? Imagine a single-family house that wants to light its garden or terrace for 8 hours every night of the year. As a remarkable point, this type of luminaire is not exclusively for summer, but can be used 365 days a year. There are two options for this:

Purchase two LED wall lights connected to the mains (16W and 800lm), the cost of the two units is approximately 40 euros both. It should be borne in mind that this option requires building work to be carried out if there is no previous electrical installation outside, plus the increase in the electricity bill, which, taking into account the time it is switched on (8 hours per day), the power (16W) and the cost of electricity (0.17€/kWh), the cost amounts to 15.67€ per year (taxes not included) for the two wall lights.

On the other hand, we can opt for the installation of two solar wall lights that do not require connection to the electricity grid, because they recharge their battery with sunlight (800 lm). The cost of the two units would amount to about 70€, although it requires a higher initial cost (70 solar – 40 electricity wall lights = 30€) it would be amortised in 2 years by the electricity cost of the traditional option (15.67 X 2 = 31.34€). This choice therefore saves money and energy beyond those two years.

In addition, we must take into account that the savings are greater, as usually not only two lamps are installed, but more. So the savings generated by the use of solar luminaires in our exteriors will be greater with the advantage that this type of product can be placed anywhere, as long as the sun shines directly on the solar panel.

Once we have all the necessary information about solar panels, it is time to buy the product. In Arteconfort we are leaders in the sale of solar products, you can buy our articles in Leroy Merlin or Bauhaus, choosing those that best suit your needs.