Energy is the ability to produce some kind of work or put something in motion.. Although the term can be defined from a wide variety of approaches, the truth is that all of them bear some kind of relationship with the definition provided. Energy is a topic of enormous relevance for human activity, insofar as it allows the development of life on earth and sustains economic activity..
The most important source of energy for man is the sun. Thus it is thanks to sunlight that plants can, through cells specially designed for this task, take energy and produce their own food that results in the production of oxygen. Thus seen the facts, vegetables are also the first source of energy in the food chain, to the extent that they serve to nourish herbivores, and from there, all other living beings, including scavengers. Indeed, the energy provided by the sun in the form of light (photons or light energy) is transformed by plants into chemical energy, stored in nutrients. This energy is in turn released as heat energy by the animals.
It is worth noting that, for the activities of production of goods and services, the requirement of energy sources is also important. It is because of that the exploitation of energy resources is of enormous importance strategic, because it is the basis on which the entire economy is put into operation. The main sources of energy in this sense are hydrocarbons, which are organic compounds that are made up of hydrogen and carbon; thus, natural gas and oil are essential for human activity to develop today. It is interesting to note that these products have originated from a slow and progressive process that had as its starting point living beings, which is why they are known as "fossil fuels". In strict terms and remembering the previous paragraph, the energy contained in these products does not stop being also originated in the sun, although thousands of years ago.
One of the main problems currently awaiting solution is the need to extract energy from new sources. A possible answer was long offered by nuclear power, but its cost and the dangerous accidents associated with it acted to the detriment of this possibility. Other variants to generate energy can be the use of the wind, the tides, the heat of the earth, the rivers, etc. In the particular case of propulsion by moving air, known as wind energy, it has been known since ancient times within the framework of the use of mills for the most varied purposes. At present, it is possible to obtain large aliquots of energy with this resource, although it is limited to windy areas. On the other hand, the movement of the waters (either through the tides or the activity of the rivers) represents a resource of great interest due to its cleanliness and its ecological characteristics, although it may depend to a great extent on climatic factors and the flow of the water courses involved in the process. The use of solar cells to accumulate energy directly from the sun's photons is a remarkable possibility, although it is recognized that a large number of cells are required to achieve this effect even for small consumers. Finally, some alternative pathways, such as wood energy (obtained from wood waste), geothermal energy (from the heat of the Earth) and bioenergy (such as gas produced by certain strains of bacteria) are a door of hope for power generation. In the future there will be new possibilities regarding this topic.