With the urgency to fight the climate changes, as renewable energy were gaining strength and space in the public debate. Increasingly, countries announce that they will increase the use of renewable sources in their matrixes, in the so-called energy transition.
The idea is to reduce the share of fossil fuels — natural gas, coal and oil — which emit carbon dioxide when they are used to generate energy.
As society’s demand for energy would not fall along with the reduction in the use of these fuels, it is necessary to find more environmentally friendly substitutes, and that is where renewable energies come in.
Brazil is one of the reference countries in the use of renewable sources in its electricity matrix. 2020 data from Ministry of Mines and Energy point out that just over 80% of the matrix is renewable, with the domain still being the so-called hydraulic source.
What is renewable energy?
According to Virgina Parente, a professor at IEE-USP, the most common definition for a renewable source is that it “does not change and is not lost” when generating energy. However, this would not apply to biomass, for example, or water used in hydroelectric plants.
Therefore, the most precise definition for this group, according to the expert, is that of a source “used at a slower speed than nature can replace in the human horizon”. This is called the sustainability rate, and it guarantees that as long as there is demand, the source will not be depleted.
That is, the definition of a renewable source depends on the context. Sugarcane bagasse is one of the main forms of biomass used to generate energy, but if the use became so intense that the sugarcane could not be planted anywhere, the source would run out at some point and therefore. would no longer be renewable.
In addition, Parente says that being a renewable energy is not synonymous with being a source of clean energy. First, she considers that “there is no such thing as a clean energy source today” if we take the definition literally.
For the source to be clean, it is necessary that it does not emit polluting gases not only in the generation of energy, but in all stages of the process, of the manufacture of the equipment used in the generation, in the transport of the source and in the elimination of produced residues.
“There is no energy generation technology that does not have a negative environmental or social externality. There are only energies that do not emit greenhouse gases at the time of generation, and renewables tend to emit much less, or not emit, greenhouse gases in energy production”, he says.
The big exception in this area is the energia nuclear. The generation process depends on uranium, which is enriched and whose atoms are separated to generate energy, in the process of nuclear fission.
As an ore, uranium has a lower rate of replacement in nature than that of use, and therefore nuclear energy is not renewable, but is clean at the time of generation. All fossil fuels are non-renewable and “dirty”.
Check out the types of renewable energy:
The latest aggregated data on Brazil’s electrical and energy matrices were released in 2021, with reference to the year 2020. In the electrical matrix, the hydraulic source corresponded to 65.2%, followed by biomass (9.1%), wind (8.8%), natural gas (8.3%) and the others.
The energy matrix is less renewable, since in this case any type of energy generation is considered, including vehicle fuels. Thus, the most used is petroleum and derivatives (33.1%), followed by sugarcane derivatives (19.1%) and hydraulics (12.6%).
In both cases, however, the share of renewable energy is higher than the global measure. Survey by the International Energy Agency (OUCH) points out that, in 2019, renewables had around 25% of share in the global electricity matrix, and less than 15% in energy. In the Brazilian case, the share is 83% and 46%, respectively.
Hydraulic sources, with hydroelectric plants, have dominated the electricity matrix for many years, but solar and wind sources have gained space as their costs have reduced, reflecting Brazil’s high potential. The expectation is that, in 2021, both will have grown, in the wake of the water crisis.
Of the renewable sources, ocean energy and green hydrogen are used only in experimental projects. This is due to high costs and lack of technology, but the country has great potential in both areas.
The only renewable energy that is impossible in Brazilian territory is geothermal, as it can only be used in places with volcanic activity or plate encounters, which is not the case in Brazil.
Reference: CNN Brasil