The renewable energies are those energies that come from natural resources and do not run out even if there are used in a constant way. The human exploitation of the energy always entails a certain impact on the environment; however, compared to the important negative effects that cause the conventional energies on the environment, the impact of the renewable ones is insignificant. Many depend on the geography and on the climate, so they cannot be found in any place.
The majority of them come from the sun in a direct or indirect way.
Another characteristic of the renewable energies is that they are consumed generally in the place where they are generated, that is, they are autochthonous sources of energy. While the fossil fuels exist just in a limited number of countries, the renewable energies reduce the dependence from external deliveries and contribute to the territory and also in the creation of jobs. In this sense, it is calculated that the renewable energies create five times more jobs than the conventional ones, which generate little employment in relation at its volume of business.
As they are local sources of energy, are more economic than the traditional sources because they entail a minor energetic loss and the economic expenses inherent to the needs of transport and distribution are also reduced.
The main renewable energies are:
- Eolian: is the energy obtained from the wind and is generated by the effect of the drafts through aero generators, and then it is transformed into useful forms for the human activities.
- Solar thermal: is the exploitation of the energy of the sun to produce heat that can be used for cooking or heating water destined to the domestic consumption or to air conditioning.
- Solar photovoltaic: is the direct transformation of the luminous energy that comes from the Sun in electrical energy through some solar panels that have photoelectric cells. The solar radiation has a value of power that changes depending on the climate, the latitude, the atmospheric conditions and the moment of the day and the seasons of the year.
- Hydraulic: comes from the exploitation of the potential energy accumulated in the waterfalls that can be transformed into electrical energy. Some turbines that scroll an electrical generator generating like this electrical energy are put in operation. With this system the movement of the water is consumed, not the water.
- Geothermal: can be obtained through the exploitation of the heat from the inside of the Earth. On a large scale geothermal energy can be used to warm water (heating, to wash cloth, etc), to industrial thermal energy or to produce electricity from the hot steam that is made pass through a turbine. At a small scale it has very diverse uses, according to the difference of temperatures achieved.
- Waves energy: this type of energy can be used with mechanisms of canalization and deposit in some strategic places, as gulfs, bays or estuaries, for obtaining movement in an axle using hydraulic turbines that are interposed in the natural movement of the waters. The energy of the waves can be produced due to the oceanic thermal gradient, due to the sea currents and the one produced by the osmotic power.
- Biomass: comes from the transformation of organic matters, as agricultural waste or trunks of trees, in caloric or electrical energy. This energy of the biomass has to be extracted from a series of processes of transformation that can be physical, like the breaking, chemical, like the pyrolysis and the gasification, or biological, like the processes of fermentation to produce alcohols and esters.
In conclusions, the renewable energies are the future because they are clean, are restored freely, and can be a part of the solution to the energetic problem in the long term. They represent the autochthonous energetic resource more important of Catalonia and its energetic exploitation reduces the external energetic dependence. Moreover, they have fewer effects related to climate change and its consequences to a planetary level.
To know more about renewable energies you can consult the web of the Institut Català d'Energia and the Town Hall of Barcelona (Barcelona Energy).
In the web of Renewable Energies Magazine you will find news about the conventional energies and the renewable ones and also in the blog of dialEc that is an agency of communication specialized in services of advice and management to help to materialize projects related with the sustainability.
In the web site of the Net for the Energetic Sovereignty (XSE) also you will find information about the renewable energies and the up-to-date energetic model.