Solar energy is a way of renewable energy obtained from the light and heat from the sun, being considered one of the cleanest and most sustainable sources of energy currently available.
The full use of this type of energy has only become possible thanks to the development of specific technologies. With the invention of devices such as collectors and photovoltaic cells, also known as solar panels, the conversion of solar energy into electricity or heat was carried out.
The advancement of these technologies and the reduction of installation costs have made solar energy increasingly accessible and widely used in homes, businesses and power plants around the world.
How solar energy works (step by step)
Solar energy is produced by capturing and converting sunlight into electrical or thermal energy. The process of generating solar energy involves the following steps:
1. Capture of sunlight
Solar panels are composed of photovoltaic cells made of semiconductor materials such as silicon. These cells have special properties that allow them to absorb sunlight.
2. photovoltaic effect
When sunlight falls on photovoltaic cells, the photons present in the light excite the electrons in the atoms of the semiconductor material. This process is called the photovoltaic effect and results in the generation of a continuous electric current.
3. Conversion into electricity
The electric current generated by the photovoltaic cells is collected and conducted by metallic wires, forming a circuit. This circuit allows electrons to flow, creating a usable electrical current.
To power electrical devices or power systems, the electricity generated by solar panels passes through an inverter, which converts direct current into alternating current.
4. Use and storage
The electricity generated by solar panels can be used immediately to power electrical appliances, lighting systems, household appliances, among other devices.
If there is a storage system, such as batteries, excess energy produced during the day can be stored for later use at night or during cloudy periods.
5. Heating
In addition to generating electricity, solar energy can also be used for thermal heating. In this case, solar collectors are used to absorb sunlight and convert heat into thermal energy.
This thermal energy can be used to heat water for domestic use, swimming pools, space heating systems or even to generate steam in power plants.
Types of solar energy (with examples)
There are different types of solar energy that can be harnessed to generate electricity or heat. The main types are:
photovoltaic solar energy
It is the most common and well-known type of solar energy. In this case, sunlight is converted directly into electricity through photovoltaic cells, present in solar panels.
These cells, usually made of silicon, absorb photons from sunlight and generate an electric current. The electrical energy produced can be used immediately, stored in batteries or injected into the electrical grid.
thermal solar energy
This form of solar energy is used for heating. Solar thermal collectors capture the energy of sunlight and convert it into heat. Solar thermal energy is an efficient and sustainable option to replace conventional heating systems.
concentrated solar energy
This type of solar energy uses mirrors or lenses to focus sunlight on a specific point, where heat is generated. This heat can be used to generate electricity through a thermodynamic cycle, similar to that used in thermoelectric plants.
Concentrated solar energy is most commonly used in large power plants, where concentration of sunlight is optimized.
passive solar energy
Unlike the types mentioned earlier, passive solar energy does not involve the direct conversion of sunlight into electricity or heat. It refers to the intelligent use of architectural and material design to make the most of sunlight and natural heat from the sun in buildings.
Examples of passive solar energy strategies include using large windows to let in light solar energy, adequate thermal insulation and positioning of buildings to take advantage of the movement of the Sun.
Advantages and benefits of solar energy
renewable energy source
Solar energy is an inexhaustible source of energy, deriving from the sun, which will continue to shine for billions of years. Unlike fossil fuels, this type of energy is not depleted and does not contribute to the scarcity of natural resources.
Low environmental impact
Solar power generation does not emit harmful air pollutants such as carbon dioxide, sulfur oxides or nitrogen oxides. This contributes to the reduction of the greenhouse effect, air pollution and associated health problems.
Long-term cost savings
While the initial costs of installing solar systems can be considerable, solar power saves money in the long run. Once installed, the sun provides free and plentiful energy, significantly reducing dependence on conventional energy providers, helping to control electricity costs.
versatile application
Solar energy can be used at different scales, from small distributed generation systems in homes to large solar power plants.
In addition, it can be used for both electricity generation and thermal heating, making it a versatile option to meet different energy needs.
Disadvantages of solar energy
Dependence on weather conditions
The amount of solar energy available varies depending on weather conditions, such as the presence of clouds, time of year and geographic location.
This means that solar energy production can be affected on cloudy days, at night and in regions with less solar radiation.
high initial costs
Installing solar systems requires a significant initial investment, including equipment purchase, installation and maintenance. While costs have come down over the years, it can still be a barrier for some people or businesses.
space needed
Deploying large-scale solar systems requires adequate space, whether on building roofs, open land or specific areas for solar plants.
In densely populated urban areas, finding enough space to meet energy demand can be a challenge.
Limited overnight availability
Solar energy is not available at night when there is no direct sunlight. This requires implementing energy storage systems, such as batteries, to ensure a continuous supply of electricity outside periods of sunlight.
Although it has some disadvantages, solar energy is widely considered a clean, sustainable energy option with great growth potential.
Use of solar energy in Brazil
Solar energy has gained increasing importance both on the world stage and in Brazil. Awareness of the environmental impacts of fossil fuels and the search for clean, renewable energy sources have driven the growth of the solar sector worldwide.
Brazil has a prominent position on the world stage when it comes to photovoltaic solar energy generation. Currently, it ranks eighth in the global ranking, with an accumulated installed capacity of 24 GW. This impressive number demonstrates the growing investment and adoption of solar energy in the country.
Solar energy has been playing a fundamental role in the diversification of the Brazilian energy matrix, especially in a context where hydroelectric dams face challenges and crises due to the scarcity of rainfall and climate changes. Solar energy generation capacity has been a valuable alternative, allowing for greater security and stability in electrical supply.
In January 2023, solar energy was consolidated as the second most used source in the Brazilian electricity matrix, representing a 12% share, surpassing wind energy and natural gas. This achievement highlights the importance and potential of this clean and sustainable energy source.
Bibliography:
- LUIZ, Adir Moyses. Solar Energy and Environmental Preservation. São Paulo: Physics Bookstore, 2013.
- TOLMASQUIM, Maurício Tiommo. Renewable Energy Sources in Brazil. Rio de Janeiro: Synergia, 2003.
- ABSOLAR (Brazilian Photovoltaic Energy Association). Panorama of photovoltaic solar energy in Brazil and in the world - infographic. https://www.absolar.org.br/mercado/infografico/. Accessed on: July 5, 2023.
See too:
- Energy
- Types of energy and sources
- Renewable energy
- Thermal energy
- wind energy
- Electricity