And, even if on a smaller scale, production also occurs on cloudy days. So, about that, you don’t have to worry.
Solar energy: know everything about it
What is solar energy?
In 1839, the French physicist Alexandre Edmond Becquerel discovered the photovoltaic effect, the potential of sunlight to generate electricity. But it was not until 1954 that the American engineer Russell Shoemaker Ohl introduced the first system as it is used today.
Solar energy uses a special system to capture sunlight and convert it for two main purposes:
Photovoltaic solar energy: transforming sunlight into electricity (it is the most used);
Solar energy heliotérmica: transform the light into heat to heat the water (it replaces, for example, the electric shower and puts hot water in the taps).
What are photovoltaic panels?
The photovoltaic plates or modules are made based on silicon, a semiconductor (conductive and insulating material that can easily change the characteristics of electrical conduction).
“In them, you have on the one hand more positive charges and, on the other hand, more negative charges. When the sun hits, this huge energy causes the negative charge to change sides. The movement of electrons is the electric current”, he explains Edval Elboni, coordinator of the electrical engineering course at Instituto Mauá de Tecnologia.
The light falls on the photovoltaic panels, but produces electric current with voltage smaller, incompatible with the appliances in your home. Therefore, it is subjected to the inverter, which changes the voltage to 127 V or 220 V.
How to install and use solar energy at home?
The system is installed by specialized companies. The first step is to calculate consumption, based on the electric bill, to estimate the best photovoltaic model. There are two options:
- off grid: night supply is guaranteed by batteries, recharged throughout the day.
- on grid: the electric network is connected to the local energy concessionaire.
In the latter case, there is a storage system that redirects the excess energy to the concessionaire. This guarantees the supply during the night and allows the consumption of energy directly from the network in case of any problem.
This energy generated the most used by the concessionaire becomes a kind of bonus with a term of five years to be used and you pay only a minimum monthly fee.
The off grid model is still little used in homes, because of the high cost of batteries.
What is the cost of solar energy?
The installation costs of the solar photovoltaic system depend on the standard in energy consumption. In a family with four people, for example, prices can vary between R $ 16,500 and R $ 18,000. The amount covers full support, installation and equipment.
According to experts heard by Tilt, the return on investment is up to five years, and the system can last up to 30 years.
“Anywhere in Brazil, the sun is very good, so the average return is four to five years. But, in the Northeast, it can be three to four years,” he says Elboni.
Can apartments use solar energy?
Apartments can also use solar energy systems, but the installation model must be made in accordance with the building. This makes the process bureaucratic and sometimes prevents the tenants from going ahead with the idea.
In addition, it is necessary to analyze whether there is adequate space on the ground for the efficient installation of the slabs and to make a shared plant for everyone.
How is the maintenance of the solar energy system?
As the plates are made to last a long time, it is essential to invest in a good project to ensure that you do not have any problems, such as lightning strikes, but in general the maintenance of the photovoltaic system is simple.
On a daily basis, you only need to check that there are no burnt modules and, when you notice the accumulation of dust, clean them with a damp cloth in water – the accumulated dirt affects the incidence of natural light and affects the performance of the system.
What are the disadvantages of solar energy?
The main disadvantages of solar energy are:
- High initial investment;
- Absence of energy production during the night;
- Low power generation when compared to other models: the efficiency of the system is relatively low, because it manages to transform 20% of what it captures into energy. “This is in the best plates, but new technologies are being developed”, says Odilon Duarte, professor of electrical engineering at PUC-RS (Pontifical Catholic University of Rio Grande do Sul)
What are the advantages of solar energy?
- Less expenses: with the payment of the minimum fee to the concessionaire, the electricity bill reduces between 90% and 95%;
- Sustainability: the system stops using coal and emits gases such as CO2 (carbon dioxide) and the CH4 (methane);
- Quick installation
- Reliable system;
- Makes no noise;
- Simple maintenance;
- Adds resale value to the property;
- Easy installation in the city, when compared to other models (such as wind energy, for example).
The main solar energy companies in Brazil
The market for photovoltaic systems in Brazil is expanding. Among the main companies in the country, the following stand out: Canadiansolar-Brazil, Avex Technology, Jinko Solar and Neosolar.
There is also a growth in small designers, who are not manufacturers, but help to quote and hire services for those who want to adhere to solar energy.
What is the rate of use of solar energy in Brazil?
The percentage of the use of solar energy in the Brazilian energy matrix is still small. The index is at 1.7%, according to data from 2021 da ABSOLAR (Brazilian Association of Photovoltaic Solar Energy).
“Although it represents little, it is the one that is growing the most”, says Edval Elboni.
Source: Edval Elboni, coordinator of the electrical engineering course at Instituto Mauá de Tecnologia; Odilon Duarte, professor of electrical engineering at PUC-RS (Pontifical Catholic University of Rio Grande do Sul).
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