The role of natural gas in the energy transition
Although speaking about fossil fuels and low-emission energy generation may at first seem contradictory, resources such as natural gas can be excellent partners on the road to decarbonisation.
Modernising our energy system from top to bottom and effectively reducing greenhouse gas emissions from its production, distribution and consumption is an essential task for the planet's conservation. But it is not an easy goal to achieve, especially given the current high dependence on traditional fossil fuels such as coal and oil.
It should be noted that although many different low-emission energy alternatives are currently being developed, implementing them throughout society is not yet on the horizon. It is therefore necessary to find other ways to renew and decarbonise energy production in the short term.
It is precisely in this scenario where materials such as natural gas can play a crucial role, especially as it is a resource present on a large scale in our energy system and can therefore act as a link between the old production model and the new, fully renewable system that we need.
What is natural gas?
It is an organic compound made up of a mixture of various gases, mainly methane, which is present in more than 95% of its composition, as established by Spanish legislation. It is one of the most widely used energy sources in our country and is commonly consumed in both in the domestic and industrial sectors.
One of its most important characteristics is that, of all the fossil fuels currently in use, natural gas has the lowest environmental impact.
This is the case not only during combustion, but also during extraction, processing and transport. The transformation process from its extraction is also minimal and consists only of a purification phase in which any impurities it may contain are eliminated.
Positive data such as the fact that its CO2 emissions into the atmosphere are half those of coal or that SO2 (sulphur dioxide) emissions are 2,500 times lower than those emitted by fuel oil make natural gas a very practical asset when it comes to advancing in the energy transition. Moreover, it is also considered a green energy by the European Parliament since last July, so its relevance is now more than evident.
How it is formed
Natural gas, like other fossil fuels, originates through a process of degradation of organic matter. This happens naturally when several layers of animal or plant matter decompose and, at the same time, are exposed to intense heat and pressures beneath the earth's surface over the course of millions of years.
For example, we can imagine a lake or sea area where large quantities of organic debris were gradually deposited at the bottom. This waste was buried under very heavy layers of sediment, enduring high temperatures and high pressure in an environment with no air at all. This type of decomposition, called anaerobic decomposition, chemically altered the matter and caused a series of gases such as natural gas to be released.
Storage and distribution
One of the most useful advantages of this component is directly related to its versatility in being handled in various states.
The most common form in which we will find natural gas is in a gaseous or dry state, which is easily stored in depleted underground gas or oil fields, aquifers, etc. This gas is transported from the fields to homes or industries by means of pipelines.
In addition, natural gas can undergo a process known as liquefaction, in which it is compressed and cooled at low temperatures to convert it into a liquid component. In this state it is known as LNG or liquefied natural gas, and in this way, it can be transported and stored by ship over long distances without the need for infrastructure or pipelines.
Also worth mentioning is CNG, or compressed natural gas, which is used as a vehicle fuel—a more sustainable solution than petrol or diesel—and is formed by storing natural gas at very high pressure.
Uses of natural gas
It is used as an energy source with high heating power in a wide range of areas and can be a good alternative to coal for power generation at all levels.
In heating, air conditioning, hot water, for both commercial and domestic use.
Through combined cycle power plants that work with gas and pressurised steam.
For ships and shipping (LNG), as well as for land vehicles (CNG).
Used in all kinds of industrial processes and fertiliser production.
Long-term outlook for the energy sector
Natural gas is the third most consumed primary energy globally, behind only oil and coal. The forecast for the coming years is that by 2050, gas consumption will remain stable in the market and may move into second place, due to the reduction in coal use and the increase in renewable energies.