The sources of energy are classified as follows:
Renewable energy sources:Energy resources which are naturally replenished but flow-limited. They are virtually inexhaustible in duration but limited in the amount of energy that is available per unit of time. Renewable energy resources include: biomass, waste energy, hydro, wind, geothermal, solar, wave and tidal energy.
Non-renewable resources: those that exist in limited quantity and that, therefore, once used in their totality cannot be substituted. This category includes nuclear energy and fossil fuels such as coal, oil and natural gas.
In recent years, natural gas has become one of the main energy sources thanks to its role of supporting renewable energies, contributing to the reduction of emissions and their greater efficiency. It also offers great possibilities of utilization due to its possibility of use with different technologies in all sectors thanks to its higher energy efficiency and low emission level, its abundance and general availability and its affordable cost.