school energy&environment

Impacts on air

The extreme flexibility of natural gas makes it one of the fuels easier to use, whereas the low content of pollutants makes it an environmentally friendly fuel. During combustion natural gas produces carbon dioxide and nitrogen oxides (NO_x), albeit to a lesser degree than other fuels.
Moreover, coal and oil by-products also produce sulphur oxides and sulphur dioxide (SO₂), two pollutants toxic for mankind and the atmosphere. Sometimes the natural gas can be burnt with coal or oil (co-firing): this process can significantly reduce the emissions of SO₂ e NO_x. Cogeneration allows to consume 25% less of energy as compared to a traditional plant and to reduce by 1% the emissions of SO₂ and by 50% NO_x emissions, as compared to a coal or oil-based plant, even if it makes use of anti-pollution equipment.
As regards carbon dioxide in particular, the International Energy Agency (IEA) assessed that, if the same amount of energy is produced, carbon dioxide emissions caused by the combustion of natural gas are smaller by 25% and 40% as compared to those produced by the combustion of oil and coal by-products.
Finally, methane presents the advantage of being virtually “invisible” both during ground transport and when it is distributed in cities (it travels through underground pipes and only pumping stations are at ground level), a feature only few other energy sources share.
Moreover, since it is gaseous at room temperature (20°C), should any leak occur during transport, it disperses into the air, does not dirty, or pollute waters or the soil.
Natural gas can damage the environment if it is dispersed in its natural state because it is one of the greenhouse gases. In other words, after reaching the top layers of the atmosphere, it stops and stays there for many years, contributing to the formation of a gas layer that prevents the solar heat reflected by the earth’s surface from being dispersed and leads to global warming (i.e. the greenhouse effect).
Therefore leaks of natural gas during its transportation should be reduced to a minimum or eliminated: not only is it a waste of a precious resource, but there is also the risk of contributing to a potentially dangerous phenomenon for mankind.