Energy transition through renewable gases

Our modern life is costing us more than we can imagine: Icebergs are melting, wildlife is battling to survive, rain forests are disappearing, weather is becoming severe, and sea levels are increasing. It is obvious that we are battling with global warming due to the increase of greenhouse gases which reached their highest levels in the last era.

What role plays the natural gas in this problem? And how can we limit it? The answer to the latter is simple: renewable gas!

To understand the need for renewable gas and their processes, first we need to understand the problem that we are facing today and its origins.

The use of fossil fuels from the pre-industrial era has released into the atmosphere greenhouse gases responsible for global warming, causing the average temperature on earth to rise by 1°C.

The human activities such as industry, heating, transportation, communication and others are releasing more and more greenhouse gases into the atmosphere. It’s mainly carbon dioxide.

It is mostly released by the combustion of fossil fuels through burning coal, oil or natural gas.

These gases accumulate and form a giant envelope all around the earth. The sun’s heat and radiation were hereby trapped under this envelope and the temperature of the planet has increased by 1°C on average since the end of the 19th century. Without action, it could reach 6°C by 2100.

Therefore, the Paris Agreement was signed in 2015 by 196 countries to keep global warming below 2°C, luckily 1.5°C, by 2100.

Natural gas is formed in the subsoils. Due to the pressure and the heat, the sediments gradually turn into hydrocarbons, such as petroleum or natural gas. This process takes millions of years.

The energy transition is the transition from the current energy system, based largely on fossil fuels, to an energy mix using mainly renewable energies.

Unlike natural gas, green gas is a renewable form of energy because it builds up over a short period of a few weeks.

To date, 3 major production processes are at the origin of renewable gas:

• The first process is anaerobic digestion. Renewable gases are mainly produced by this process and are known by biomethane.

Anaerobic digestion uses agricultural wastes, food industries wastes and urban wastes to produce biomethane. This gas comes from the fermentation of organic matters, which are transformed into biogas, that will be purified and odorized subsequently to become biomethane.

• The second process is pyro-gasification. The latter uses the combustion of non-organic waste at high temperature to produce biomethane.

Pyro-gasification burns wastes such as wood and solid recovered fuels to produce a syngas. The latter is then purified to become a renewable gas that is injected into the gas network.

• The last process is power-to-gas. This process makes it possible to convert the excess of renewable electrical energy into hydrogen or biomethane which can be stored in the gas network.

Renewable electricity is mainly solar, wind or hydro. It is produced when the elements are favorable, but not necessarily when it is needed.

In order to optimize this electricity, the surplus must be stored. Currently it is complicated to store it in large quantities. However, green gas is a storable solution. Due to electrolysis, the renewable electric current passes through water to separate the molecules of hydrogen and oxygen. This pure hydrogen can be directly integrated into the gas network up to a certain percentage.

Another power-to-gas process is methanation. The latter consists on recovering carbon dioxide from factories, non-hazardous waste storage facilities and sewage treatment plants, and on combining it with hydrogen to create synthetic methane. This methane is injected into the distribution network since it has the same characteristics of natural gas and biomethane.

Today, major gas companies are changing the core of their operations to make renewable gases the center of their business model. It Is the only way they can survive global warming and the new environmental restrictions. However, will it be enough to slow down the impact of gas on global warming or even to stop it?