Solar energy is electromagnetic energy whose source is the sun. It can be transformed into thermal or electrical energy and applied to various uses. The two main ways of using this type of energy are electricity generation and solar water heating.
The production of electrical energy can be done from two systems. The first, called heliotherm, converts solar radiation into thermal energy and, later, into electrical energy. The second, which is called photovoltaic, convert solar radiation directly into electrical energy.
Despite the belief that installation is complicated or bureaucratic, photovoltaic solar energy is an economical, practical, and safe alternative for obtaining clean energy. If you are interested in the complete installation – including financing – of a solar energy system in your home, without a headache, please fill out the form below to receive a quote.
Heliothermal energy or concentrated solar energy
Under unfavorable hydrological conditions, with longer and longer periods of drought, heliothermal energy presents itself as an alternative. Even more so if we consider those periods of drought are associated with increased solar potential, due to low cloud interference and more intense solar radiation.
In this scenario, there are several types of collectors, and the choice of the most appropriate depends on the application. The most used are the parabolic cylinder or disc and the central tower.
Collectors are equipment that captures solar radiation and converts it into heat, transferring it to a fluid. They have a reflective surface, which directs the radiation to a focus, where a receiver is located. Once it has absorbed heat, the fluid flows through the receiver.
Photovoltaic solar energy
The solar photovoltaic is one in which solar radiation is converted directly into electrical energy, without passing through the thermal power stage (as would be the heliothermic system).
How it works?
Photovoltaic cells are made from semiconductor materials, usually silicon. When the cell is exposed to light, part of the electrons in the illuminated material absorbs photons, that is, particles of energy present in sunlight.
Free electrons are transported by the semiconductor until they are pulled by an electric field, which is formed at the junction area of the materials by a potential difference. They are then taken out of the solar energy cells and made available to be used in the form of electrical energy.
Unlike the heliothermic system, the photovoltaic system does not require high solar radiation to function. However, the amount of energy generated depends on the density of the clouds. A high number of clouds can result in less electricity production compared to completely open skies days.
According to the Ministry of the Environment, the government develops photovoltaic solar energy generation projects to meet the energy demands of rural and isolated communities. These projects focus on areas such as pumping water for domestic supply, irrigation and fish farming, public lighting, collective use systems (electrification of schools, health centers, and community centers), and home care.
Another way of using solar radiation is thermal heating. It is usually done through a process of absorption of sunlight by collectors, which are installed on the roofs of buildings and homes.
As the incidence of solar radiation on the Earth’s surface is low, it is necessary to install a few square meters of collectors. According to the National Electric Energy Agency, in order to supply the heated water supply to a residence of three to four residents, 4 m2 of collectors are needed.
Although the demand for this technology is predominantly residential, there is also interest from other sectors, such as public buildings, hospitals, restaurants, and hotels.
If you are interested in installing a solar heating system in your home and being one of the energy generators, check out the Guide for installing solar energy at home.
Advantages and Disadvantages of Solar Energy
Solar energy has several advantages. Unlike fossil fuels, the process of generating electricity from solar panels does not emit sulfur dioxide, nitrogen oxides, and carbon dioxide. These pollutants, with harmful effects on human health, contribute to global warming. Therefore, solar energy can be considered a renewable energy source.
On the other hand, installing solar panels requires large spaces. Thus, it is important to analyze the most appropriate location for the implantation, since there will be suppression of vegetation.
In addition, another point to be considered concerns the environmental impact caused by the raw material used to compose the photovoltaic cells: silicon.
Silicon mining causes several environmental impacts, such as soil and water pollution. It is also essential that good working conditions are provided to workers, in order to avoid work accidents and the development of occupational diseases.
The International Agency for Research on Cancer (IARC) points out, in a report, that crystalline silica is carcinogenic and can cause lung cancer when chronically inhaled.
True value of solar energy
For years, some utility companies feared that solar panels would increase electricity costs for people without panels. However, research conducted by experts has shown that the owners of this grid-connected technology are actually subsidizing their neighbors.
“Anyone who installs solar panels is being a great citizen to their neighbors and to their local utility,” suggests the survey leader.
“Customers with distributed generation are preventing utilities from having to make so many investments in infrastructure. At the same time, solar energy reduces peak demands when electricity is more expensive.”
“Solar value” is becoming the preferred method for evaluating the economics of grid-tied photovoltaic systems. However, the calculations are challenging and there is widespread disagreement in the literature about the methods and data needed to perform them.
To overcome these limitations, experts analyzed previous studies to develop a generalized model that considers realistic costs and responsibilities that utilities can avoid when people install grid-connected solar panels.
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