Worldwide, the use of solar energy is growing significantly, both to reduce the costs of the electricity bill and to contribute to environmental preservation.
In Brazil, solar energy was the fastest growing source in 2024, according to data from the National Electric Energy Agency (Aneel). This growth represents the addition of 5.62 gigawatts (GW) of capacity in centralized generation plants compared to a total of 10.85 GW generated the previous year.
Investments in the sector also drive the Brazilian economy. In 2024, the country attracted R $ 54.9 billion to finance solar energy generation projects, resulting in the creation of over 429 thousand related jobs, according to data from the Brazilian Association of Photovoltaic Solar Energy (ABSOLAR).
Despite the continuous increase in demand for this source of energy, the theme still raises many doubts. To better understand how solar energy works and know the main advantages and disadvantages of this technology, continue reading below.
What is solar energy?
As its name implies, solar energy is the energy generated from the light and heat of the sun.
It is common to associate the concept of solar energy with sustainability, as it is a clean energy source. This is due to the fact that its generation does not release greenhouse gases or other pollutants, as it depends solely on sunlight and specific fundraising systems, as we will see below.
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What will serve?
The energy from the sun can be used as a substitute for various sources of fossil and polluting energy. Among its applications, we can highlight:
- Water heating and environments
- Electronic appliances recharge
- Electric car recharge
- Electricity generation
- Power generation for industries
- Pumping of artesian wells
- Hydrogen production, which can be used to store energy and as a raw material in various industries
How does it work?
To use solar energy, it is necessary to convert it to electrical energy, which occurs through the photovoltaic effect.
Solar plates contain photovoltaic cells, whose main component is silicon, a semiconductor responsible for the phenomenon. When sunlight reaches these plates, the photons (particles that carry sunlight) shift the electrons present in the material, thus generating electricity.
The electric current generated by the movement of the electrons in the solar plates is continuous type. However, sockets, appliances, machines and other devices that use electricity operate in alternating current.
At this point, another important component comes in the generation of solar energy: the inverter. The function of this equipment is to convert direct current into alternating current and send it to the distribution board, allowing the energy generated in the photovoltaic process to be used.
Briefly, this is how solar energy works in homes, companies, public spaces and other places that use it.
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Another important aspect to consider is that solar panels do not capture energy at night. During the day, even on cloudy or rainy days, there is incidence of ultraviolet rays, although to less than sunny days. In this situation, the panels operate with less intensity, but the energy is still generated.
Systems
Photovoltaic systems can be classified into two types: on-grid and off-grid. The main difference between them is in the storage of surplus energy, as we will see below.
On-grid
In the on-grad system (the most used), the energy in the distribution board is connected to the utility’s power grid.
In this process, the user has a meter that indicates the amount of energy they consume and how much is sent to the network. At night and at times of low energy production, the distributor’s network provides electricity to the site.
When solar energy production is higher than consumption, the surplus is sent to the public network and returns to the user in the form of credits. Depending on the case, these credits may even exempt the electricity bill, keeping only the minimum charge of the government.
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Off-grid
Typically, the off-grid system is used in remote places that do not have access to distribution networks as it operates disconnected from the external network.
In this case, there are batteries that store the generated energy, ensuring that the user is not affected by interruptions or energy oscillations in the region.
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Although autonomy is a strong point of this type of system, the high installation cost of batteries makes it more expensive than the on-grid system.
How much does it cost?
Although autonomy is a strong point of this type of system, the high installation cost of batteries makes it more expensive than the on-grid system.
In addition to the solar panels, the costs involved include labor, cabling and other expenses related to system installation. The amount of panels required depends on the demand of residents and the location of the residence.
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For example, a family that needs air conditioning in every room will need more panels than a person who lives alone, even if both houses are the same size. In addition, those who reside in regions with higher solar incidence need fewer photovoltaic systems than those living in less sunny places, and so on.
Over the past three years, the price of solar panels has dropped about 60%, according to a survey of the my solar financing platform. The study, which compared the amounts charged by more than 3,000 companies, revealed that the return to those who invested in roof -installed photovoltaic systems ranged from 35% to 45%, depending on the project and the installation region.
Here’s a financing and return simulation of solar energy systems:
| Consumer type | System power | Average price | Economy in the Light Account | Annual economy | Annual return rate |
| Residential | 5kwp | R$ 12.906 | R$ 400 | R$ 4.800 | 37% |
| Residential | 6,6kwp | R$ 16.988 | R$ 500 | R$ 6.000 | 35% |
| Residential | 7,6kwp | R$ 18.165 | R$ 600 | R$ 7.200 | 40% |
| Residential | 8,8kWp | R$ 20.518 | R$ 700 | R$ 8.400 | 41% |
| Residential | 10kWp | R$ 22.692 | R$ 800 | R$ 9.600 | 42% |
| Residential | 12.2KWP | R$ 26.318 | R$ 1.000 | R$ 12.000 | 46% |
| Commercial | 25.5kwp | R$ 54.500 | R$ 2.000 | R$ 24.000 | 44% |
| Commercial | 50.5kwp | R$ 122.900 | R$ 4.000 | R$ 48.000 | 39% |
(Source: My Solar Financing – January/2025)
Advantages
Some of the main advantages of investing in photovoltaic systems include:
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Cheaper electricity bill
The credit system may result in a significant reduction in the electricity bill.
According to the Solar Portal, users with a photovoltaic system pay between 50% and 95% less on the dealership invoice. Also, if the system is off-grid, it can cover 100% of local consumption.
HIGH RETURN PERSPECTIVES
According to Carolina Reis, CEO of my solar financing, the prospects for the Brazilian Solar Distributed Generation (GD) market are very positive.
In an interview with the Solar Portal, the executive stated that one of the reasons for this optimism is the uniqueness of Brazil, which makes it almost “armored” of local economic instability. For the installation of photovoltaic systems, the country depends on imported equipment, especially on China, and the price of these equipment has fallen expressively in recent decades.
“In addition to becoming cheaper, photovoltaic equipment is increasingly efficient, which increases attractiveness and further reduces the return of investment to the consumer,” the CEO told the portal.
Low environmental impact
Solar energy is a great ally of (environmental, social and governance). Its adoption helps minimize greenhouse gas emissions and strengthens the use of sustainable arrays, contributing to environmental preservation.
Autonomy
Photovoltaic systems provide more autonomy to users as they reduce dependence on electrical networks. This is particularly advantageous when supply is unstable in certain locations, or prices are very high.
Property appreciation
All the benefits mentioned above contribute to the valorization of the property that has solar energy generation. According to Absollage, the increase in market value can reach 10% with the installation of photovoltaic panels.
Disadvantages
On the other hand, some factors contribute so that this kind of energy is not so popular. Among them, we can highlight:
High initial cost
Although there are credit lines aimed at financing photovoltaic systems, the initial cost is still considered high in Brazil. Studies indicate that, depending on the consumer standard, it may be necessary for 3 to 7 years for the user to notice the financial benefits of the investment.
Climate dependence
Although solar panels work on sunshine days, their efficiency decreases considerably on rainy or cloudy days. This can result in instability in the supply of solar energy, especially in locations with these.
Storage limitations
In recent years, battery banks that store solar energy have evolved significantly in terms of technology. However, when compared to other sources of energy, their efficiency still leaves something to be desired.
