What Are Renewable Energy?
Renewable energies come from natural resources such as sun, wind, rain, tides, which are renewable (which are renewed and not exhausted).
Hydropower comes from the movement of water. It is produced by taking advantage of the hydraulic potential existing in a river, using artificial unevenness (dams) which causes the flow of falling water to trigger a turbine which in turn will generate electricity.
Solar energy comes from the Sun (thermal and light energy). This energy is captured by photovoltaic cells, which is composed of a photovoltaic solar panel, which by an electrochemical process (static, non-mechanical) transforms energy from the sun into electrical energy. Solar energy is also used directly to heat water through solar collectors.
Wind energy is the kinetic energy contained in moving air masses (wind). The use of this resource is done by converting the kinetic energy of translation into kinetic energy of rotation, with the use of wind turbines, also called wind turbines, for the generation of electricity, or weathervanes (and mills) for mechanical work like pumping water.
Biomass are natural residues and residues resulting from human activity. Biomass can be used directly as fuel, or through its biodegradation produce a fuel gas, called biogas. In either situation, the heat produced can be used directly in heating, or for the production of steam, which will drive a turbine, to produce electricity.
Other Important Concepts In The Field Of Renewable Energy
The development that seeks to satisfy the needs of the current and future generations using natural, renewable and non-polluting resources of the earth, without compromising the sustainability and preservation of our planet's resources, as well as preserving species and natural habitats. Energy Efficiency and Renewable Energies are the two main pillars of a sustainable energy policy.
Energy Efficiency is about the rational use of energy. It consists of using energy as efficiently as possible to obtain a certain result, resulting in significant savings in energy consumption, for this it is essential to use electrical devices that consume as little as possible, an example is the use of "LED" lighting ” (Light-Emitting Diode, in Portuguese Light Emitting Diode) which has a much higher light output per unit of energy consumed. The use of renewable energies as an energy source to ensure electricity needs, as well as air conditioning and domestic hot water heating is also an Energy Efficiency measure, as it decisively contributes to reducing fossil fuel energy consumption and much more pollutants.
In light of the Paris Agreement, at the time of the United Nations climate conference (COP21) held in December 2019 in the French capital, a vast number of countries, including Angola, pledged to achieve neutrality in emissions of carbon by the second half of the 21st century. But what does this mean in practice? Climate change is already affecting the entire planet, with extreme weather conditions such as droughts, heat waves, river floods, floods and landslides becoming more and more frequent. Other consequences of these rapid climate changes include rising sea levels, ocean acidification and loss of biodiversity. To limit global warming to 1.5 degrees Celsius – the limit considered safe by the Intergovernmental Panel on Climate Change (IPAC) – carbon neutrality is essential by 2050. This goal is also defined in the Paris Agreement, signed by 195 countries.
What is carbon neutrality?
The neutrality of carbon emissions is the balance between emissions and the absorption of this gas from the atmosphere made by the so-called carbon sinks. To reduce global greenhouse gas emissions to zero, they must be offset by carbon sequestration. A carbon sink is any system that absorbs more carbon than it emits. The main natural carbon sinks are soil, forests and oceans. According to estimates, natural sinks remove between 9.5 and 11 Gt of CO2 emissions from the atmosphere per year. Annual global CO2 emissions reached 37.1 Gt in 2017.
Another way to reduce carbon emissions and achieve neutrality is to offset these emissions from one sector by reducing them in another sector. This can be achieved through investment in renewable energy, energy efficiency or other clean, low-emission technologies. The EU Emissions Trading Scheme is an example of a carbon offsetting system.