| In international statistics, the electricity is considered as primary energy or as derived energy. The primary energy is produced from natural sources such as: water, wind, solar energy, tides and waves energy. The derived energy is produced from heat produced in the process of combustion of primary fuels (coal, natural gas) as well as from derived and renewable energy commodities and combustible wastes. The derived electricity can be also obtained from geothermal or solar heat. |
